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Sample records for cerebellopontine angle presenting

  1. Cerebellar glioblastoma multiforme presenting as a cerebellopontine angle mass

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    Anupam Jindal

    2006-01-01

    Full Text Available Cerebellar glioblastoma multiforme (GBM is a highly malignant brain tumour, which is exceedingly rare and such tumour presenting as cerebellopontine angle (CPA mass is even rarer. We here discuss the case of a 15-year-old girl who had cerebellar GBM presenting as CPA mass that resembled meningioma on CT scan and was managed successfully with minimal problems.

  2. Arteriovenous malformation in the cerebellopontine angle presenting as trigeminal neuralgia

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    Paulo C. Figueiredo

    1989-03-01

    Full Text Available A case of arteriovenous malformation of the left cerebellopontine angle causing symptoms of ipsilateral trigeminal neuralgia is reported. Pain relief followed microsurgical removal of the malformation. The authors review the literature on the subject.

  3. Cerebellopontine angle Hodgkin's disease

    International Nuclear Information System (INIS)

    Intracranial Hodgkin's disease is a rare site of involvement, and even more rare is its presentation as a cerebellopontine angle mass. It can be difficult to diagnose especially when recurrent tumors occur because both CT and lumbar puncture have been shown to have a relatively low yield. Gadolinium-enhanced MRI is more sensitive. It is concluded that while the imaging findings can be non-specific, the rapid response to therapy (steroids) may provide a clue to diagnosis. Copyright (1999) Blackwell Science Pty Ltd

  4. Facial nerve neurinoma presenting as middle cranial fossa and cerebellopontine angle mass : a case report.

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    Devi B

    2000-10-01

    Full Text Available Facial nerve neurinomas are rare. The tumours arising from the geniculate ganglion may grow anteriorly and superiorly and present as a mass in the middle cranial fossa. Only a few cases of facial nerve neurinomas presenting as middle cranial fossa mass have so far been reported. These tumours present with either long standing or intermittent facial palsy along with cerebellopontine angle syndrome.

  5. Epidermoid cyst causing hemifacial spasm epidermoid cyst in cerebellopontine angle presenting with hemifacial spasm

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    Murat Alemdar

    2012-01-01

    Full Text Available Hemifacial Spasm (HS occurs idiopathically or secondary to the lesions compressing the root exit zone of the facial nerve symptomatically. Symptomatic HS is generally due to vascular compression. We report on a 23-year-old male with right sided HS for a month. Magnetic resonance imaging (MRI of the brain revealed a well-demarcated epidermoid cyst in the right cerebellopontine cistern. It was hypointense on T1-weighted imaging, hyperintense on T2-weighted imaging without contrast enhancement, hyperintense on DWI, and slightly hypointense on ADC relative to the brain. Although it caused shifting of the pons and medulla to the left side and compression of the right cerebellar peduncles and fourth ventricle, the sole symptom of the patient was HS. Clinicians are advised to request MRI/scan for brainstem lesions from the patients with HS. Epidermoid cysts in cerebellopontine cistern may present with HS as the sole symptom.

  6. Epidermoid cyst in the cerebellopontine angle cistern presenting as trigeminal neuralgia

    International Nuclear Information System (INIS)

    This 29-year-old male had been suffering from left trigeminal neuralgia one year prior to admission. Admission was prompted by the development of pain in the third division of the left trigeminal nerve. Physical and neurological examinations were not remarkable except for the facial pain. The orbicularis oculi reflex showed delayed latency of R1 on the affected side. CT scans performed pre- and post-contrast enhancement revealed a low density area in the left cerebellopontine angle cistern. Metrizamide CT cisternography clearly revealed the margin of the lesion as the contrast media did not enter into the low density area. A left suboccipital craniectomy was performed. The trigeminal nerve was surrounded by a thin-capsulated mass and cholesteatoma materials. Histological diagnosis was epidermoid cyst. Since this surgical procedure, the trigeminal neuralgia has not recurred for one year. Without objective neurological deficits, it is difficult to distinguish symptomatic trigeminal from idiopathic neuralgia. Therefore, minor change of the orbicularis oculi reflex should help in objectively detecting dysfunction of the trigeminal nerve. Metrizamide CT cisternography is also useful in diagnosis of cystic lesions. (author)

  7. A case of right cerebellopontine-angle lesion: psychotic symptoms and magnetic resonance imaging findings.

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    Jung, Min Soo; Lee, Byung Dae; Park, Je Min; Lee, Young Min; Moon, Eun Soo

    2012-09-01

    Here, we report psychotic symptoms together with a right cerebellopontine-angle lesion. A37-year-old female patient presented with a trigeminal Schwannoma occupying the right cerebellopontine angle. Her psychotic symptoms included auditory hallucinations and delusions of persecution. T1- and T2-weighted images on magnetic resonance imaging (MRI) revealed hyperintense and hypointense areas in the right cerebellopontine angle, respectively. The clinical and neuroimaging reviews in this case suggest that sudden onset of psychotic symptoms at a mature age may be associated with a right cerebellopontine-angle lesion and that MRI should be used to evaluate possible organic bases in patients that present with psychosis. PMID:22993532

  8. Solitary Fibrous Tumor of the Cerebello-Pontine Angle

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    Biggs, Nigel D.; Fagan, Paul A.; Turner, Jennifer J.; Doust, Bruce

    1999-01-01

    A case is presented of solitary fibrous tumor occurring in the cerebello-pontine angle. There have been only two other reported cases of a solitary fibrous tumors in this region. Imaging studies showed the tumor to be characteristic in shape and position of an acoustic tumor. However, at surgery the tumor was found to have a “rock hard” consistency. Solitary fibrous tumor differs from acoustic schwannoma and meningioma in its histopathological features and in this case, regrowth, after incomplete excision, was extremely rapid. ImagesFigure 2Figure 3Figure 4Figure 5Figure 6 PMID:17171119

  9. Malignant melanoma of the cerebello-pontine angle region

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    F. Menezes Braga

    1989-12-01

    Full Text Available A case of malignant melanoma in the cerebello-pontine angle region is presented in a 72 years old female patient, who had neurological examination and CT scan suggestive of acoustic neuroma. The surgical finding and the histological examination provided the diagnosis. As a primary focus was not found on clinical examination and although autopsy was not carried out, there is a possibility of the diagnosis being a primary malignant melanoma in CNS. This specific location for this kind of tumor was found to be rare when literature is looked up.

  10. Disorders of the cerebellopontine angle; Klinik der Kleinhirnbrueckenwinkelerkrankungen

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    Block, F. [Helios-Kliniken Schwerin (Germany). Neurologische Klinik

    2006-03-15

    Disorders of the cerebellopontine angle may present by symptoms like vertigo, hearing problems, affection of the trigeminal or facial nerve. Ipsilateral ataxia and contralateral hemiparesis develop in case of a rather large tumor in this region and display an involvement of the cerebellum and/or brainstem. However, some of these typical symptoms are not recognized by the patient. Thus, in case of a suspicion of a disorder of the cerebellopontine angle the relevant functions have to be tested clinically. In addition, electrophysiology can confirm dysfunction of these cranial nerves. Mainstay of the therapy should be the treatment of the underlying cause. Nevertheless, not seldom it is necessary to treat symptoms like vertigo or facial pain. (orig.) [German] Schwindel, Hoerstoerungen, Affektionen des N. trigeminus oder des N. facialis stellen die wesentlichen und haeufigen Symptome bei Kleinhirnbrueckenwinkelerkrankungen dar. Ipsilaterale Gliedmassenataxie und kontralaterale Hemiparese sprechen fuer eine Mitbeteiligung von Kleinhirn und/oder Hirnstamm, die meist nur bei grossen Prozessen in dieser Region auftreten. Da einige Veraenderungen sich fuer den Patienten unbemerkt entwickeln, ist bei Verdacht eine gezielte klinische Untersuchung dieser Funktionen angezeigt, die durch elektrophysiologische Diagnostik wie z. B. akustisch evozierte Potenziale oder Blinkreflexe untermauert werden kann. Auch wenn natuerlich die kausale Therapie im Vordergrund steht, ist es gar nicht selten notwendig, eine symptomatische Behandlung durchzufuehren. Dies trifft besonders fuer Symptome wie Schwindel oder Gesichtsschmerzen zu. (orig.)

  11. Endolymphatic sac tumor : a rare cerebellopontine angle tumor.

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    Joseph B

    2002-10-01

    Full Text Available Endolymphatic sac tumors (ELST are rare papillary tumors of the temporal bone. Previously named as aggressive papillary middle ear tumors, they have recently been shown to arise from the endolymphatic sac. They are a rare in cerebello-pontine angle (CPA. We present a case of an ELST who presented as a CPA tumor with hydrocephalus. He underwent a ventriculo-peritoneal shunt initially. On exploration of the CP angle, the tumor was found to be extremely vascular. He was re-explored following embolization, and a subtotal excision of the tumor was done. Extensive petrous bone infiltration and vascularity of the tumor makes total excision almost impossible with high risk of cranial nerve deficits, excessive blood loss and CSF leak. This tumor should be considered in the differential diagnosis of vascular CPA tumors which erode the petrous temporal bone. The relevant literature is reviewed.

  12. Epidermoid cyst in the cerebellopontine angle cistern presenting as trigeminal neuralgia. Diagnostic values of the orbicularis oculi reflex and metrizamide CT cisternography - case report -

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    Ueda, Takashi; Goya, Tomokazu; Kinoshita, Kazuo (Miyazaki Medical College, Miyazaki (Japan)); Fukui, Masashi

    1983-05-01

    This 29-year-old male had been suffering from left trigeminal neuralgia one year prior to admission. Admission was prompted by the development of pain in the third division of the left trigeminal nerve. Physical and neurological examinations were not remarkable except for the facial pain. The orbicularis oculi reflex showed delayed latency of R/sub 1/ on the affected side. CT scans performed pre- and post-contrast enhancement revealed a low density area in the left cerebellopontine angle cistern. Metrizamide CT cisternography clearly revealed the margin of the lesion as the contrast media did not enter into the low density area. A left suboccipital craniectomy was performed. The trigeminal nerve was surrounded by a thin-capsulated mass and cholesteatoma materials. Histological diagnosis was epidermoid cyst. Since this surgical procedure, the trigeminal neuralgia has not recurred for one year. Without objective neurological deficits, it is difficult to distinguish symptomatic trigeminal from idiopathic neuralgia. Therefore, minor change of the orbicularis oculi reflex should help in objectively detecting dysfunction of the trigeminal nerve. Metrizamide CT cisternography is also useful in diagnosis of cystic lesions.

  13. Neuronavigation assisted decompression of trigeminal neuralgia caused by cerebellopontine angle osteoma

    OpenAIRE

    Iimura Yasushi; Saitou Rikizou; Abe Kazuhiro; Tsunoda Akira; Maruki Chikashi; Arai Hajime

    2014-01-01

    Trigeminal neuralgia (TN) is usually caused by vascular compression of the trigeminal nerve root entry zone, but can be caused by other factors such as tumors, vascular disorders, and demyelination in multiple sclerosis. We present a rare case with a huge osteoma located on the cerebellopontine angle (CPA) and causing TN. A 48-year-old woman presented with TN caused by a huge left CPA bone tumor. Surgery was performed by the lateral suboccipital approach under neuronavigation system guidance ...

  14. Cerebellopontine angle lipomas: magnetic resonance imaging findings in two cases

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    Borges, Rafael S. [Clinica de Diagnostico por Imagem Multi-Imagem, Rio de Janeiro, RJ (Brazil); Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Dept. de Radiologia; Brito, Cecilia Castelo Branco [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Fac. de Medicina; Carvalho, Gustavo A. [Clinica Bambina, Rio de Janeiro, RJ (Brazil). Dept. de Neurocirurgia; Hospital Silvestre, Rio de Janeiro, RJ (Brazil); Domingues, Romeu C. [Clinicas CDPI e Multi-Imagem, Rio de Janeiro RJ (Brazil); Gasparetto, Emerson L. [Clinicas CDPI e Multi-Imagem, Rio de Janeiro RJ (Brazil)

    2009-07-01

    Vestibular schwannomas and meningiomas are the most common lesions of the cerebellopontine angle (CPA), accounting for approximately 85-90% of the tumors seen in this location. Lipomas are rare at this topography, representing about 0.15% of the CPA lesions. These tumors are mal developmental masses that arise from abnormal differentiation of the meninx primitive. Clinically, CPA lipomas can cause slowly progressive neurological symptoms and signs affecting cranial nerves or brain stem. Because these lesions usually are strongly attached to the surrounding structures, any surgical attempts of complete resection can result in neural or vascular damage, reinforcing the importance of the pre-operative imaging diagnosis. Although the CT findings of CPA lipomas can be typical, the magnetic resonance (MR) imaging, especially the fat suppression sequences, had improved the identification of these lesions. We aimed to report two patients with a CPA lipoma, emphasizing the MR imaging findings. (author)

  15. Vascular anomalies of the cerebellopontine angle; Vaskulaere Erkrankungen des Kleinhirnbrueckenwinkels

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    Papanagiotou, P.; Grunwald, I.Q.; Politi, M.; Struffert, T.; Ahlhelm, F.; Reith, W. [Universitaetsklinikum des Saarlandes, Homburg/Saar (Germany). Klinik fuer Diagnostische und Interventionelle Neuroradiologie

    2006-03-15

    Vascular anomalies of the cerebellopontine angle are rare compared to tumors in this area. Irritation of the trigeminal, facial, or vestibulocochlear nerve may cause trigeminal neuralgia, hemifacial spasm and vertigo, or tinnitus accordingly. Vessel loops in the cerebellopontine cisterns may cause compression at the root entry or exit zone of the cranial nerves V, VII, and VIII, a phenomenon which is called ''vascular loop syndrome.'' Megadolichobasilar artery and aneurysms of the vertebrobasilar system can also lead to dislocation and compression of the cranial nerves and brain stem. Three-dimensional CISS MR imaging and MR angiography are useful in the detection of neurovascular compression. Microvascular decompression is an effective surgical procedure in the management of compression syndromes of the cranial nerves V, VII, and VIII. (orig.) [German] Gegenueber den Raumforderungen stellen vaskulaere Veraenderungen des Kleinhirnbrueckenwinkels eher eine Ausnahme dar. Trigeminusneuralgie, hemifazialer Spasmus und Schwindel oder Tinnitus koennen bei Irritationen des Nervus trigeminus, facialis und vestibulocochlearis auftreten. Schlingenbildungen der Gefaesse in den Kleinhirnzisternen koennen eine Kompression der Eintritts- oder Austrittszonen der Hirnnerven V, VII und VIII am Hirnstamm hervorrufen, was als ''Vascular-loop-Syndrom'' bezeichnet wird. Zu Verlagerungen und Kompressionen von Hirnnerven und Hirnstamm koennen, wenn auch seltener, die Megadolichobasilaris und Aneurysmen des vertebrobasilaeren Systems fuehren. Bezueglich der Bildgebung ist die Magnetresonanztomographie (MRT) die Methode der Wahl. Die 3D-CISS-Sequenz und die MR-Angiographie sind hilfreich zur Darstellung der neurovaskulaeren Kompression. Die Methode der mikrovaskulaeren Dekompression ist eine wirkungsvolle Methode zur Beseitigung gefaessbedingter Kompressionen der Hirnnerven V, VII und VIII. (orig.)

  16. Surgical Outcomes of Cerebellopontine angle Tumors in 50 Cases

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    faramarz memari

    2015-01-01

    Full Text Available Introduction: To report our experience with a large series of surgical procedures for removal of cerebellopontine angle (CPA tumors using different approaches.   Materials and Methods: This was a retrospective analysis of 50 patients (mean age, 49 years with CPA tumors (predominantly acoustic neuroma who underwent surgical removal using appropriate techniques (principally a translabyrinthine approach during a 4-year period.   Results: One death occurred during this study. There were nine cases (18% of cerebrospinal fluid leak, and five patients (10% were diagnosed as having bacterial meningitis. Complete gross tumor removal was not achieved in four patients (8%. Facial nerve function as measured by the House Brackmann system was recorded in all patients 1 year following surgery: 32% had a score of 1 or 2; 26% had a score of 3 or 4; and 8% had a score of 5 or 6. Other complications included four cases of wound infection.   Conclusion:  The translabyrinthine approach was predominantly used in our series of CPA tumors, and complication rates were comparable with other large case series.

  17. Cerebral salt wasting syndrome: postoperative complication in tumours of the cerebellopontine angle.

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    Ruiz-Juretschke, Fernando; Arístegui, Miguel; García-Leal, Roberto; Fernández-Carballal, Carlos; Lowy, Alejandro; Martin-Oviedo, Carlos; Panadero, Teresa

    2012-02-01

    Cerebral salt wasting (CSW) is a rare complication in posterior fossa tumour surgery. We present two patients with cerebellopontine angle (CPA) tumours who developed cerebral salt wasting postoperatively. Both patients deteriorated in spite of intensive fluid and salt replacement. On CT scan the patients presented mild to moderate ventricular dilation, which was treated with an external ventricular drainage. After the resolution of hydrocephalus, fluid balance rapidly returned to normal in both patients and the clinical status improved. Identification and treatment of secondary obstructive hydrocephalus may contribute to the management of CSW associated to posterior fossa tumour surgery.

  18. Solitary fibrous tumor of the cerebellopontine angle: A case report and literature review

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    Joe M Das

    2014-01-01

    Full Text Available Solitary fibrous tumors (SFT are rare dura-based mesenchymal tumors of the central nervous system. SFT occurring in the cerebellopontine (CP angle is very rare and only 21 cases have been reported in the literature until date. We present a 40-year-old male patient who presented with features of the right-sided facial and acoustic nerves paresis along with same sided cerebellar symptoms of 2 months duration. Magnetic resonance imaging revealed a T2 heterogeneously hyperintense extra-axial lesion, showing intense contrast enhancement in the right CP angle with solid and cystic areas. The lesion was not extending into the internal auditory canal. Digital subtraction angiography showed arterial feeders from vertebro-basilar system. The highly vascular lesion was excised near-totally by suboccipital retrosigmoid craniectomy. The lesion was diagnosed as SFT on histopathological examination and was positive for CD34 and bcl-2.

  19. Cerebellopontine angle epidermoid showing a positive enhancement upon metrizamide CT cisternography

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    Hasegawa, Takeshi; Wakamatsu, Koichi; Fujii, Toshiharu; Ito, Haruhide; Yamamoto, Shinjiro; Nagata, Izumi

    1985-04-01

    A case of epidermoid tumor in the left cerebellopontine angle cistern is reported in a 43-year-old woman with left trigeminal neuralgia. Plain CT scan revealed a low density area at the left cerebellopontine angle and left ambient cisterns, which could not be differentiated from their enlargement. Metrizamide CT cisternography showed an irregular, high density pattern in the low density filling defect which was extending into the suprasellar and interpeduncular cisterns. The developmental mechanism of this specific finding in the metrizamide CT cisternography was discussed on the basis of morphological characteristics of epidermoid tumor.

  20. An uncommon case of lymphoplasmacytic lymphoma in cerebellopontine angle region: Case report with a literature review.

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    Yan, Chengrui; Kong, Xiangyi; Yang, Lanshu; Ma, Wenbin

    2016-08-01

    In the central nervous system, cerebellopontine angle (CPA) lymphomas are rare; few cases have been reported. Lymphoplasmacytic lymphoma (LPL) in the CPA is rarer still, and often misdiagnosed as acoustic neuroma.We report a rare case of CPA LPL-a challenging diagnosis guided by clinical presentations, radiological signs, and postoperative pathological test.A 43-year-old woman presented with headaches. Her magnetic resonance imaging revealed an abnormal homogeneously enhancing mass in the left CPA. We present detailed analysis of her disease and review relevant literature.When surgically treated, her specimen showed a typical LPL histopathology pattern. After surgery, the patient's symptoms improved greatly, and she received chemotherapy.Despite its rarity, LPL should be considered in differential diagnoses of CPA lesions that mimic acoustic neuromas. PMID:27559959

  1. Nonvestibular schwannoma tumors in the cerebellopontine angle: A structured approach and management guidelines

    DEFF Research Database (Denmark)

    Springborg, J.B.; Poulsgaard, L.; Thomsen, Jens Christian

    2008-01-01

    The most common cerebellopontine angle (CPA) tumor is a vestibular schwannoma, but one in five CPA tumors are not vestibular schwannomas. These tumors may require different management strategies. Compared with vestibular schwannomas, symptoms and signs from cranial nerve VIII are less frequent...

  2. Neuronavigation assisted decompression of trigeminal neuralgia caused by cerebellopontine angle osteoma

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    Iimura Yasushi

    2014-09-01

    Full Text Available Trigeminal neuralgia (TN is usually caused by vascular compression of the trigeminal nerve root entry zone, but can be caused by other factors such as tumors, vascular disorders, and demyelination in multiple sclerosis. We present a rare case with a huge osteoma located on the cerebellopontine angle (CPA and causing TN. A 48-year-old woman presented with TN caused by a huge left CPA bone tumor. Surgery was performed by the lateral suboccipital approach under neuronavigation system guidance and regional decompression of the trigeminal nerve root entry zone was achieved. Intraoperative, neuro-navigation system was very useful for identification of the trigeminal nerve entry zone because normal anatomy had been obscured by the huge osteoma. Her pain disappeared completely immediately after surgery. The histological diagnosis was osteoma. TN is an expectative symptom of CPA tumors. Osteomas should be considered in patients with CPA tumors.

  3. Late metastasis of breast adenocarcinoma into internal auditory canal and cerebellopontine angle: case report

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    Marques Edilson

    2002-01-01

    Full Text Available A case of metastasis of breast adenocarcinoma into the internal auditory canal (IAC and cerebellopontine angle (CPA is presented, which appeared 16 years after primary tumor had been treated by surgery and radiation therapy. The 66-year old patient was considered cured from the primary disease, when she started with a rapidly developing hearing loss and intermittent facial palsy. Magnetic resonance image (MRI displayed an intra- and extracanalicular tumor mass, which radiologically resembled a vestibular schwannoma. Surgery was performed and histopathological studies showed an adenocarcinoma compatible with breast origin. Metastasis is a rare occurrence within the IAC and CPA. Clinical history of severe facial palsy will rise suspicion of malignant tumor in spite of the radiological findings.

  4. Imaging diagnosis of various small lesions in the cerebellopontine angle by Suboccipital air CT cisternography

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    Tsukahara, Kaoru (Toho Univ., Tokyo (Japan). School of Medicine)

    1989-11-01

    A modified air CT cisternography technique, characterized by suboccipital air infusion was carried out in a total of 180 patients over the past 5 years. The patients were divided into two groups according to their suspected lesions. The first group consisted of 151 patients who were diagnosed as having retrolabyrinthine lesions by neurootological examinations; 29 patients with facial twitching or trigeminal neuralgia were classified in the second group. In the first group, air CT cisternography revealed 21 cases of small acoustic tumors including intracanalicular tumors. Additionally, several unexpected small lesions were detected in the cerebellopontine angle. These included small meningiomas, osteoma, osteogenic tumor, nodulated acoustic nerve in neurofibromatosis, primary acoustic nerve atrophy, adhesive arachnoiditis, elongated basilar artery and patulous acoustic meatus. In the second group, the causative artery of neurovascular compression at the nerve exit zone failed to be confirmed in many cases, but satisfactory preoperative information concerning nerves and vessels in the cerebellopontine angle were provided by air CT cisternography. The advantages and disadvantages of air CT cisternography and MRI-CT for the diagnosis of small lesions in the cerebellopontine angle are also discussed. (author).

  5. An adult case of medulloblastoma in the cerebellopontine angle extending to the supratentorial area

    Institute of Scientific and Technical Information of China (English)

    Yasemin Benderli Cihan

    2010-01-01

    Medulloblastoma is an undifferentiated embryonic neuroepithelial tumor. It is a rare tumor in the central nervous system, with an even rarer occurrence during adulthood. It may develop at an atypical and uncommon site, such as the cerebellopontine angle (CPA), and such tumors rarely present with supratentorial extension. The present study reports an adult case of medulloblastoma in the CPA extending to the supratentorial area. The patient presented with complaints of headache, vertigo, hearing difficulty in the left ear, nausea/vomiting, and unsteady gait. Disequilibrium began 4 weeks earlier. Examination revealed normal cranial nerves, and computed tomography showed a hyperdense lesion, with a heterogeneously enhancing mass, in the left CPA region. The patient underwent a nearly total excision of the lesion in the CPA region.Histopathological examination confirmed medulloblastoma, WHO grade IV. Postoperatively, the patient received radiotherapy and remained asymptomatic for 30 months. However, he received two more surgeries for relapse and progression of medulloblastoma and eventually died. A CPA medulloblastoma with supratentorial extension is relatively rare in the clinic.

  6. A comparative anatomical CT study of the vascular and nervous structures of the cerebello-pontine angle

    International Nuclear Information System (INIS)

    The arteries and veins of the cerebellopontine angle have been injected with a contrast medium permitting a precise anatomical reconnaissance of their topography and relations. These specimens have been explored by CT in order to define the opacified vessels and to differentiate them from the adjacent nervous tissue. Thus in CT it is possible to locate the cerebellar arteries, the petrous and medullo-pontine veins and the nerves of the cerebello-pontine angle. This study describes the normal appearance of the flocculus on CT and the criteria to distinguish the flocculus from the arteries and veins. Moreover it should contribute to the definition of the criteria of reliability of a CT diagnosis and its limits in the cerebello-pontine angle. (orig.)

  7. Cystic angiomatous meningioma in the cerebellopontine angle mimicking hemangioblastoma

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    Deb Prabal

    2010-01-01

    Full Text Available We hereby report an extremely unusual case of cystic angiomatous meningioma in the CPA region in a 58-year-old male patient. He presented with complaints of headache, repeated episodes of vomiting and increasing unsteadiness of gait. Neuroimaging showed a large multicystic left-sided tentorial tumor projecting into the cerebellum and CPA with contrast-enhancing peripheral solid rim. He underwent a left retromastoid craniectomy and total excision of the tumor. Histopathology revealed an angiomatous meningioma with predominant microvascular component and extensive cystic changes. Immunopositivity for epithelial membrane antigen (EMA, vimentin and S-100 protein proved vital in excluding a hemangioblastoma.

  8. An Unusual Case of Large Posterior Fossa Neurenteric Cyst Involving Bilateral Cerebellopontine Angle Cisterns: Report of a Rare Case and Review of Literature

    International Nuclear Information System (INIS)

    Intracranial neurenteric cysts are rare cystic masses of endodermal origin lined with mucin producing low columnar or cuboidal epithelium. Approximately 141 cases have been reported so far. Most of the posterior fossa neurenteric cysts are typically small, located anteriorly to the brainstem in the midline or in the cerebellopontine angle cistern area. We present a rare, histologically proven case of a large lobulated intracranial neurenteric cyst measuring 4.2 centimeters in the maximal transverse dimension and involving bilateral cerebellopontine angle cisterns. We also present a review of the literature on this uncommon finding. Imaging features of neurenteric cyst are non-specific and it should be considered in the differential diagnosis for any intracranial extraaxial cystic lesion

  9. Lipoma do ângulo pontocerebelar: relato de caso Lipoma of the cerebellopontine angle: case report

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    WALTER JOSÉ FAGUNDES-PEREYRA

    2000-09-01

    Full Text Available Os lipomas do ângulo pontocerebelar são tumores muito raros. Em geral são assintomáticos, achados fortuitos em autópsia, tomografia computadorizada (TC de crânio ou ressonância nuclear magnética do encéfalo. Os autores apresentam o caso de paciente, feminina, branca, 14 anos, há três anos com diminuição da audição à esquerda e há um ano com cefaléia, tipo hemicrânia à esquerda. A TC de crânio evidenciou lesão hipodensa, sem captação de contraste, no ângulo pontocerebelar esquerdo. A paciente foi submetida a cirurgia por via retrossigmóidea para abordagem da lesão, que se apresentou de coloração amarelada, característica de tecido adiposo. Tendo em vista o envolvimento de estruturas nervosas (VII e VIII nervos cranianos, optou-se pela exérese parcial da lesão. A paciente evoluiu com melhora da cefaléia, sem piora do déficit auditivo. Após três anos de seguimento, mantém o quadro estável. Conclui-se que os lipomas do ângulo pontocerebelar, quando assintomáticos, podem ser tratados conservadoramente. Entretanto aqueles associados a sintomatologia persistente e progressiva devem ser operados. A exérese total ou parcial vai depender do envolvimento ou não das estruturas neurovasculares adjacentes.Lipoma of the cerebellopontine angle is a very rare tumor. We report the case of a 14-years-old female, with left side deafness during three years, associated with headache. CT scan showed an hypodense mass, without enhancement at the cerebellopontine angle. The patient was treated surgically by left retrosigmoid approach. The lesion involved the eighth and seventh cranial nerves and only a partial removal was performed. The postoperative course was uneventful. She had no more headache; the deafness of the left side remained unchanged. Asymptomatic lipoma of the cerebellopontine angle can be treated conservatively, although those with progressive symptoms should be treated surgically, with total or partial remove

  10. Chronic Lyme disease with an expansive granulomatous lesion in the cerebellopontine angle.

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    Mokry, M; Flaschka, G; Kleinert, G; Kleinert, R; Fazekas, F; Kopp, W

    1990-09-01

    Expansive granulomatous lesions in the posterior cranial fossa are rare and have not been reported in conjunction with Lyme disease. We report a patient with verified Borrelia burgdorferi infection who developed a tumor in the cerebellopontine angle. Rapid growth of the tumor led to signs of cerebral compression and to hydrocephalus. Surgical intervention was required despite florid meningitis. The histological examination showed inflammatory, nonspecific granulation tissue. The origin of this tissue is almost certainly causally related to the B. burgdorferi infection. Signs of inflammation resolved rapidly after subtotal resection. The clinical, radiological, and biochemical course is documented. This is the first report of an expansive cerebral lesion in the chronic phase of Lyme disease.

  11. Metastatic Adenocarcinoma of Unknown Primary in the Bilateral Cerebellopontine Angles: Case Report and Review of the Literature.

    Science.gov (United States)

    Zhang, Dao-Bao; Zheng, Nian-Dong

    2015-01-01

    Metastatic adenocarcinoma in bilateral cerebellopontine angles (CPA) is rare. We report a case and review the current literature in order to enhance recognition of metastatic adenocarcinoma in the cerebellopontine angle. A 44-year-old man was referred to the hospital with rightsided diminished hearing for 7 weeks, left-sided facial palsy for 2 weeks, and left-sided sensorineural hearing loss for 1 week. On Magnetic Resonance Imaging (MRI) two tumors in bilateral CPAs were detected. The left-sided tumor was resected and histopathological examination revealed an adenocarcinoma. Many investigations could not find the primary tumor. One should be careful with middle-aged or elderly patients with sudden progressive deficits in the VIII th or VII th cranial nerves, particularly in bilateral CPA. PMID:26617145

  12. Metastatic Extrapulmonary Small Cell Carcinoma to the Cerebellopontine Angle: A Case Report and Review of the Literature

    Directory of Open Access Journals (Sweden)

    Debebe Theodros

    2015-01-01

    Full Text Available Extrapulmonary small cell carcinomas (EPSCC are rare malignancies with poor patient prognoses. We present the case of a 63-year-old male who underwent surgical resection of a poorly differentiated small cell carcinoma, likely from a small intestinal primary tumor that metastasized to the cerebellopontine angle (CPA. A 63-year-old male presented with mild left facial paralysis, hearing loss, and balance instability. MRI revealed a 15 mm mass in the left CPA involving the internal auditory canal consistent with a vestibular schwannoma. Preoperative MRI eight weeks later demonstrated marked enlargement to 35 mm. The patient underwent a suboccipital craniectomy and the mass was grossly different visually and in consistency from a standard vestibular schwannoma. The final pathology revealed a poorly differentiated small cell carcinoma. Postoperative PET scan identified avid uptake in the small intestine suggestive of either a small intestinal primary tumor or additional metastatic disease. The patient underwent whole brain radiation therapy and chemotherapy and at last follow-up demonstrated improvement in his symptoms. Surgical resection and radiotherapy are potential treatment options to improve survival in patients diagnosed with NET brain metastases. We present the first documented case of skull base metastasis of a poorly differentiated small cell carcinoma involving the CPA.

  13. Neuro-otological findings and CT scanning of cerebellopontine angle tumors

    International Nuclear Information System (INIS)

    Clinical evaluation was carried out on 13 cerebellopontine angle tumors which consisted of ten acoustic neuromas, two meningiomas and one facial nerve neurinoma. The relationship among the neurootological findings and CT scaning findings and gross appearance of the tumors were summarized as follows: 1) Many acoustic neuromas had initial symptoms of hearing loss associated with equilibrium disturbance and/or gait disturbance at the time of diagnosis of tumors. As further increase in tumor size occurs, the patients tended to complain of a great variety of neurologic symptoms and nystagmus. With further enlargement in tumor size, appearance rate of abnormality in OKP test and ETT tended to be higher. 2) The acoustic neuromas which consisted mostly of cystic mass tended to show less hearing loss and nystagmus than those which consisted mostly of solid mass. 3) Caloric response appeared abnormal in all cases of acoustic neuroma. 4) In all cases of acoustic neuroma, Stenvers view and frontal tomographic sections of petrous pyramids showed enlargement of the internal audiotory canal. Plain CT scanning of acoustic neuromas tended to reveal iso-density or low density area. Contrast enhanced CT scanning tended to reveal ring-like high density area. Acoustic neuroma with ring-like high density on the CT scanning consisted of not only cystic mass but also solid mass. 5) In cases of meningioma and facial nerve neuroma, neuro-otological findings were scanty. 6) In ABR, none of the patients showed response or the presense of wave I only or waves I and II or the abnormality of interaural latency difference. (author)

  14. Clinicopathologic study of endolymphatic sac tumor (ELST) and differential diagnosis of papillary tumors located at the cerebellopontine angle.

    Science.gov (United States)

    Du, Jiang; Wang, Junmei; Cui, Yun; Zhang, Cuiping; Li, Guilin; Fang, Jingyi; Yue, Shenglin; Xu, Li

    2015-10-01

    We investigated the clinicopathologic features and immunophenotypes of 10 cases of endolymphatic sac tumor (ELST) and compared them with other papillary tumors, including eight cases of choroid plexus papilloma (CPP), three cases of atypical choroid plexus papilloma (ACPP), two cases of papillary ependymoma (PE), three cases of papillary meningioma (PM) and two cases of metastatic carcinoma (MC) the at cerebellopontine angle (CPA). The age at onset of ELST ranged from 13 to 39 years. The male-to-female ratio was 1:1. The clinical presentations were primarily ear-related symptoms. The temporal bones showed extensive destruction. Histologically, the important characteristics for differential diagnosis with CPP, which is most similar to ELST, include the quantity of blood vessels, the nuclei location at apical surface of the papillary, clear cytoplasm cells sometimes with visible vacuoles, psammoma bodies and dura or bone invasion. Immunohistochemistry stains for AE1/AE3, cytokeratin CK)5/6, epithelial membrane antigen, CK8/18, S-100, and synaptophysin are helpful in diagnosis of ELST. In ELST, ultrastructure of uniform 2 μm vesicles in cytoplasm was seen, and gene analysis also showed missense mutation in exon 3. This study indicates that the above histological features combined with immunohistochemistry findings are important for making the correct diagnosis. Gene analysis should be used in patients without medical history to exclude von Hippel-Lindau disease. PMID:25944396

  15. Does the location of a vascular loop in the cerebellopontine angle explain pulsatile and non-pulsatile tinnitus?

    Energy Technology Data Exchange (ETDEWEB)

    Nowe, V.; Wang, X.L.; Gielen, J.; Goethem, J.Van; Oezsarlak, Oe.; De Schepper, A.M.; Parizel, P.M. [University of Antwerp, Department of Radiology, Edegem (Belgium); Ridder, D. De [University of Antwerp, Department of Neurosurgery, Edegem (Belgium); Heyning, P.H.Van de [University of Antwerp, Department of Otorhinolaryngology, Edegem (Belgium)

    2004-12-01

    The purpose was to investigate patients with unexplained pulsatile and non-pulsatile tinnitus by means of MR imaging of the cerebellopontine angle (CPA) and to correlate the clinical subtype of tinnitus with the location of a blood vessel (in the internal auditory canal or at the cisternal part of the VIIIth cranial nerve). Clinical presentation of tinnitus and perceptive hearing loss were correlated. In 47 patients with unexplained tinnitus, an MR examination of the CPA was performed. Virtual endoscopy reconstructions were obtained using a 3D axial thin-section high-resolution heavily T2-weighted gradient echo constructive interference in steady state (CISS) data-set. High-resolution T2-weighted CISS images showed a significantly higher number of vascular loops in the internal auditory canal in patients with arterial pulsatile tinnitus compared to patients with non-pulsatile tinnitus (P<0.00001). Virtual endoscopy images were used to investigate vascular contacts at the cisternal part of the VIIIth cranial nerve in patients with low pitch and high pitch non-pulsatile tinnitus. A significantly different distribution of the vascular contacts (P=0.0320) was found. Furthermore, a correlation between the clinical presentation of non-pulsatile tinnitus (high pitch and low pitch) and the perceptive hearing loss was found (P=0.0235). High-resolution heavily T2-weighted CISS images and virtual endoscopy of the CPA can be used to evaluate whether a vascular contact is present in the internal auditory canal or at the cisternal part of the VIIIth cranial nerve and whether the location of the vascular contact correlates with the clinical subtype of tinnitus. Our findings suggest that there is a tonotopical structure of the cisternal part of the VIIIth cranial nerve. A correlation between the clinical presentation of tinnitus and hearing loss was found. (orig.)

  16. Trauma-induced auditory nerve degeneration due to cerebellopontine(CP) angle manipulations:clinical and experimental experience

    Institute of Scientific and Technical Information of China (English)

    Tetsuji Sekiya

    2004-01-01

    In order to investigate the pathophysiologic mechanisms responsible for trauma-induced hearing disturbances due to auditory nerve degeneration, we established for the first time a rat experimental model in which auditory nerve degeneration due to compression injury of the cerebellopontine (CP) angle portion of the auditory nerve can be quantitatively evaluated. In this paper, Ⅰ demonstrate our clinical experience in CP angle surgery and some of the results of our experiments performed onthis rat experimental model. Trauma-induced hearing loss in CP angle operations has long been regarded as a sort of unavoidable "natural course"and therefore hopeless.I believe that this pessimistic view should be challenged and changed through new approaches in scientific research.

  17. Clinical Use of Skull Tap Vestibular Evoked Myogenic Potentials for the Diagnoses of the Cerebellopontine Angle Tumor Patients

    Directory of Open Access Journals (Sweden)

    Erdem Yavuz

    2014-01-01

    Full Text Available Objective. To document our experiences using a new skull tapping induced Vestibular Evoked Myogenic Potentials (tap VEMPs technique combined with standard Auditory Vestibular Evoked Myogenic Potentials (AC VEMPs for advanced clinical assessment of cerebellopontine angle tumor (CPAT patients. Design and Study Sample. Three patients were selected in order to highlight observations shown in a larger patient population and to show the variability of the findings. Both tap VEMPs and AC VEMPs were acquired from the sternocleidomastoid muscle (SCM with EMG-based biofeedback and monitoring. Results. The usefulness of VEMPs was demonstrated, indicating the presence of a tumor and contributing additional information as to the involved nerve bundles in two out of the three cases. Conclusion. Due to the sensory organ dependency and related innervations differences, acquiring both AC VEMPs and tap VEMPs is likely to increase the probability of diagnosing CPATs and provide more information on the involved vestibular nerve bundles. This study demonstrates the feasibility of the possible expansion and combination of tap VEMPs and AC VEMPs techniques into a clinical diagnostic battery for advanced assessment of CPAT patients and its contribution as a guideline for the use of tap VEMPs in general.

  18. MRI of the cerebellopontine angle in patients with cleido-cranial dysostosis; MRT der Kleinhirnbrueckenwinkelregion bei Patienten mit Dysostosis cleido-cranialis

    Energy Technology Data Exchange (ETDEWEB)

    Scherer, A.; Engelbrecht, V.; Nawatny, J.; Moedder, U. [Duesseldorf Univ. (Germany). Inst. fuer Diagnostische Radiologie; Messing-Juenger, M. [Duesseldorf Univ. (Germany). Neurochirurgische Klinik; Reifenberger, G. [Duesseldorf Univ. (Germany). Inst. fuer Neuropathologie

    2001-04-01

    Purpose: Cleidocranial dysostosis (CCD) is an autosomal dominant bone disorder in which deafness is common secondary to malformation of the middle ear structures. The study aimed at MRI evaluation of the cerebellopontine angle in 7 patients with a history of CCD - two generation spanned relatives. Material and methods: Cranial MRI in 7 patients with CCD (4 women/3 men aged between 8 and 46 years) was performed. In two patients hearing disorders were present. The examinations encompassed multi-planar spinecho sequences of the cerebellopontine angle in 3-mm slice thickness before and after administration of contrast medium. Results: The clinically most conspicuous female patient (hearing loss, ataxia, headache) showed a strongly contrast-enhancing tumor in MRI that was histologically proved to be an acoustic schwannoma. Concerning the other family members, no pathological findings were noted except for non-pneumatized mastoids. Conclusion: The first report of a patient with CCD and an acoustic schwannoma shows that in case of hearing loss in these patients also a retrocochlear cause must be considered. (orig.) [German] Ziel: Die Dysostosis cleido-cranialis (DCC) ist eine autosomal-dominant erbliche Knochenerkrankung, bei der aufgrund von Mittelohrmissbildungen gehaeuft Hoerstoerungen beobachtet werden. Wir ueberpruefen bei 7 von diesem Syndrom betroffenen Verwandten 1. und 2. Grades, ob sich kernspintomographisch Auffaelligkeiten der Kleinhirnbrueckenwinkelregion nachweisen lassen. Material und Methoden: MRT-Untersuchungen des Schaedels bei 7 Patienten mit DCC (4 Frauen, 3 Maenner im Alter zwischen 8 und 46 Jahren). Bei zwei Patienten lagen klinisch Hoerstoerungen vor. Die Bildgebung umfasste multiplanare Spin-Echo-Sequenzen und wurde im Bereich des Kleinhirnbrueckenwinkels in 3 mm Schichtdicke vor und nach Gadoliniumgabe durchgefuehrt. Ergebnisse: Die klinisch auffaelligste Patientin (progredienter Hoerverlust, Ataxie, Cephalgien) zeigte in der MRT einen kraeftig

  19. Benign and malignant lesions in the region of the inner ear and cerebellopontine angle; Benigne und maligne Veraenderungen der Innenohr- und Kleinhirnbrueckenwinkelregion

    Energy Technology Data Exchange (ETDEWEB)

    Czerny, C.; Nemec, S.; Krestan, C. [Medizinische Universitaet Wien (Austria). Klinik fuer Radiodiagnostik; Gstoettner, W. [Universitaetsklinikum Frankfurt am Main (Germany). Klinik fuer HNO-Erkrankungen

    2006-03-15

    Tumorous lesions in the region of the inner ear and cerebellopontine angle are very rare and can be classified into benign and malignant disease forms. This contribution presents and explains the CT and MRI characteristics of these tumors. High-resolution computed tomography (HRCT) in the axial projection is applied for evaluation in the high-resolution bone window. The coronary slices can be reconstructed from the axial datasets or in individual cases examined in the coronary plane. HRCT excellently demonstrates osseous lesions and in individual cases - e.g., exostoses - it can simply suffice to perform HRCT of the temporal bone, while HRCT is also excellent for detecting osseous lesions to determine whether the tumor is benign or malignant. MRI, on the other hand, excellently shows the extent of tumor spread because of its superb soft tissue contrast. Consequently, HRCT and MRI images of the inner ear and cerebellopontine angle provide meaningful information for visualization and classification of tumorous lesions. The two methods should not be considered as competing but rather as complementary and among other aspects exert considerable influence on the therapeutic approach. (orig.) [German] Tumoroese Veraenderungen der Innenohr- und Kleinhirnbrueckenwinkelregion sind sehr selten und koennen in benigne und maligne Erkrankungen eingeteilt werden. In dieser Arbeit sollen die CT- und MRT-Charakteristika dieser Tumoren erlaeutert und dargestellt werden. Die hochaufloesende Computertomographie (HRCT) kommt in axialer Schichtfuehrung, in der Auswertung im hochaufloesenden Knochenfenster, zum Einsatz. Die koronalen Schichten koennen aus den axialen Datensaetzen rekonstruiert oder in einzelnen Faellen in koronaler Ebene untersucht werden. Die HRCT zeigt exzellent die knoechernen Veraenderungen, und es kann in Einzelfaellen - wie z. B. bei Exostosen - genuegen, lediglich eine HRCT des Schlaefenbeins anzufertigen, waehrend auch mit der HRCT exzellent Knochenveraenderungen

  20. A Rare Case of Radiologically Not Distinguishable Coexistent Meningioma and Vestibular Schwannoma in the Cerebellopontine Angle – Case Report and Literature Review

    Directory of Open Access Journals (Sweden)

    Juergen Grauvogel

    2010-08-01

    Full Text Available Background: The simultaneous occurrence of cerebellopontine angle (CPA meningioma and vestibular schwannoma (VS in the absence of neurofibromatosis type 2 or history of irradiation is very rare. We report a case with coexistent CPA meningioma and VS, which were radiologically not distinguishable in preoperative imaging. Case Description: A 46-year-old female presented with acute hearing loss, tinnitus and gait ataxia. Otorhinolaryngological diagnostic workup and imaging studies showed an intra- and extrameatal homogenous contrast enhancing lesion. The neuroradiological diagnosis was VS. The patient was operated via the retrosigmoid approach. Intraoperatively two distinct tumors were found: a small, mainly intrameatally located VS and a larger meningioma originating from the dura of the petrous bone. Both tumors were completely microsurgically removed. The patient experienced no new neurological deficit after surgery; particularly facial nerve function was completely preserved. Histopathological examination revealed a fibromatous meningioma and a VS, respectively. Conclusions: The coincidental occurrence of CPA meningioma and VS is very rare. Careful interpretation of imaging studies before surgery is crucial. Even such rare cases should be kept in mind when discussing the therapeutic options with the patient. More studies are needed for a better understanding of mechanisms leading to multiple tumor growth.

  1. Enterococcal cerebellopontine angle abscess in a 12-year-old female

    Directory of Open Access Journals (Sweden)

    Sonavane Alka

    2010-01-01

    Full Text Available Despite advances in imaging and antibiotic treatment, brain abscess is still encountered occasionally. Various aerobic and anaerobic bacteria have been reported as causative agents of brain abscess but only a few cases of enterococcal brain abscesses have been reported. Here we report a case of brain abscess in a 12-year-old female patient, who presented with a history of fever, chills, headache, convulsions since seven days and history of altered sensorium and aphasia since the last two days . The patient had chronic suppurative otitis media of both ears following trauma and presented with ear discharge. The diagnosis of brain abscess was done by computerized tomography scan and the pus was aspirated by left suboccipital burr hole operation. Enterococcus species was cultured from the aspirated pus sample. The patient responded to surgical drainage and antibiotic treatment.

  2. Air cisternography of the cerebellopontine angle using high-resolution computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.W.

    1984-05-01

    While high-resolution CT/air cisternography is considered the preferred method of investigating non-enhancing or small acoustic neuromas, it is not without pitfalls. Eight such studies were reviewed, emphasizing procedural problems and sources of interpretive error. Two patients presented difficulty in transporting the air bolus due to a spinal cord tumor coexisting with bilaterial acoustic neuromas; spinal cord decompression was required in one case. Three potential false positives were avoided by persistent efforts to fill the internal auditory canal. Of 4 patients thought to have a tiny acoustic neuroma, elective vestibular nerve section in 2 revealed no evidence of tumor.

  3. Trigeminal Neuralgia Caused by Cerebellopontine Angle Arteriovenous Malformation Treated With Gamma Knife Radiosurgery.

    Science.gov (United States)

    Işik, Semra; Ekşi, Murat Şakir; Yilmaz, Baran; Toktaş, Zafer Orkun; Akakin, Akin; Kiliç, Türker

    2016-01-01

    Trigeminal neuralgia is a facial pain syndrome characterized as sudden onset and lightening-like sensation over somatosensorial branch(es) of fifth cranial nerve. Rarely, some underlying diseases or disorders could be diagnosed, such as multiple sclerosis, brain tumors, and vascular malformations. The authors present a 47-year-old man with trigeminal neuralgia over left V2 and V3 dermatomes. He had a previous transarterial embolization and long use of carbamazepine with partial response to treatment. Gamma knife radiosurgery (GKR) was planned. A marginal dose of 15 Gy was given to 50% isodose line. His pain was relieved by GKR in 1.5 years. Treatment of posterior fossa arteriovenous malformations causing trigeminal neuralgia, with GKR has a very limited use in the literature. It, however, is obvious that success rate as pain relief, in a very challenging field of functional neurosurgery, is satisfactory. Large series, however, are in need to make a more comprehensive statement about efficacy and safety of the procedure in these pathologies. PMID:26674920

  4. Imaging of cerebellopontine angle lesions: an update. Part 2: intra-axial lesions, skull base lesions that may invade the CPA region, and non-enhancing extra-axial lesions

    Energy Technology Data Exchange (ETDEWEB)

    Bonneville, Fabrice; Chiras, Jacques [Pitie-Salpetriere Hospital, Department of Neuroradiology, Paris (France); Savatovsky, Julien [Adolphe de Rothschild Foundation, Department of Radiology, Paris (France)

    2007-11-15

    Computed tomography (CT) and magnetic resonance (MR) imaging reliably demonstrate typical features of vestibular schwannomas or meningiomas in the vast majority of mass lesions responsible for cerebellopontine angle (CPA) syndrome. However, a large variety of unusual lesions can also be encountered in the CPA. Covering the entire spectrum of lesions potentially found in the CPA, these articles explain the pertinent neuroimaging features that radiologists need to know to make clinically relevant diagnoses in these cases, including data from diffusion- and perfusion-weighted imaging or MR spectroscopy, when available. A diagnostic algorithm based on the lesion's site of origin, shape and margins, density, signal intensity and contrast material uptake is also proposed. Non-enhancing extra-axial CPA masses are cystic (epidermoid cyst, arachnoid cyst, neurenteric cyst) or contain fat (dermoid cyst, lipoma). Tumours can also extend into the CPA by extension from the skull base (paraganglioma, chondromatous tumours, chordoma, cholesterol granuloma, endolymphatic sac tumour). Finally, brain stem or ventricular tumours can present with a significant exophytic component in the CPA that may be difficult to differentiate from an extra-axial lesion (lymphoma, hemangioblastoma, choroid plexus papilloma, ependymoma, glioma, medulloblastoma, dysembryoplastic neuroepithelial tumour). (orig.)

  5. Trigeminal Neuralgia Caused by Pontocerebellar Angle Epidermoid Tumor: A Case Report and Review of Literature

    OpenAIRE

    Muhammet Bahadır Yılmaz; Semra Yılmaz; Ayhan Tekiner

    2015-01-01

    Trigeminal neuralgia (TN) is the most commonly seen craniofacial pain syndrome. Etiology of TN can be divided into classical (idiopathic and vascular compression) and symptomatic (tumor, demyelinating, and ischemic) types. Especially, symptomatic trigeminal neuralgia is seen with tumors located in the cerebellopontine angle. Epidermoid tumors comprise about 1% of all brain tumors and 5% of tumors located in the cerebellopontine angle. These tumors may present with trigeminal neuralgia due to ...

  6. 桥小脑角区小型占位致继发性三叉神经痛的手术疗效分析%Surgical outcome after resection of small cerebellopontine angle lesions resulted in secondary trigeminal neuralgia

    Institute of Scientific and Technical Information of China (English)

    陶传元; 魏攀; 庄进学; 陈登奎; 程宏炜; 宋朝理; 李海龙; 薛峰; 张炜; 郑小强

    2011-01-01

    目的 评估桥小脑角区(CPA)小型占位致继发性三叉神经痛的手术疗效.方法 回顾分析我科自2005年1月~2010年12月期间该类患者的临床资料,包括年龄、症状及体征、影像学表现、手术方式、疗效及并发症.结果 6年期间手术治疗三叉神经痛372例,其中CPA区小型病变(最大直径<3cm)致继发性三叉神经痛23例,约占6.2%;病种包括胆脂瘤12例、神经鞘瘤6例、脑膜瘤3例、蛛网膜囊肿2例;所有患者行乙状窦后入路显微镜下切除病变,3例另行三叉神经感觉根部分切断术;术后疼痛消失20例,面部麻木3例;术后并发症包括无菌性脑膜炎、脑脊液漏、颅内感染、短暂耳鸣及面瘫,均恢复,无死亡.随访1~5年,无疼痛复发.结论 CPA区小型占位所致继发性三叉神经痛患者由于病变小、易于全切,加之镜下暴露充分,手术疗效满意;术中若发现病变与三叉神经无确切关系,则需行微血管减压或三叉神经部分感觉根切断术.%Objective To evaluate the surgical outcome after resection of small cerebel-lopontine angle lesions resulted in secondary trigeminal neuralgia (TN). Methods Clinical data including age, symptom and sign, image manifestation, surgical modality, surgical outcome and complications in patients diagnosed secondary TN resulted from small cerebellopontine angle lesions are analyzed retrospectively between 2005. 1 and 2010. 12. Results Of 6 years duration, 372 cases of TN underwent operations. There were 23 cases of such kind (the largest diameter less than 3cm) accounting for 6. 2% among them which involved 12 cholesteatomas, 6 schwanno-mas, 3 meningiomas and 2 arachnoid cysts. All lesions were resected under microscope through retrosigmoid approach and additional partial sensory rhizotomy was performed in 3 cases. After operation, 20 cases got complete pain relief and the rest had facial numbness. Postoperative complications included aseptic

  7. Malformação da transição crânio-vertebral como causa de síndrome do ângulo ponto-cerebelar: relato de dois casos Cerebello-pontine angle syndrome associated with cranio-vertebral malformation: report of two cases

    Directory of Open Access Journals (Sweden)

    Amauri Batista da Silva

    1972-03-01

    Full Text Available Os autores relatam dois casos de síndrome do ângulo ponto-cerebelar nos quais não havia neoplasia nessa região. Ambos os pacientes apresentavam uma associação de impressão basilar com síndrome de Arnold-Chiari. Após cirurgia descompressiva de fossa posterior os casos evoluiram favoravelmente com a diminuição progressiva dos sintomas neurológicos, restando apenas, no segundo paciente, certo grau de paralisia e de espasmo facial, à direita. São feitas considerações em tôrno das causas mais freqüentes da síndrome do ângulo ponto-cerebelar, bem como acêrca dos quadros clínicos mais usualmente encontrados em doentes que apresentam malformações da transição crânio-vertebral. Finalmente, os autores tecem breves considerações a respeito do possível mecanismo lesionai do VIII, do V e do VII nervos cranianos nos dois casos relatados.Two cases of cerebelo-pontine angle syndrome associated with basilar impression and Arnold-Chiari malformation are reported. In both cases neuroradiological studies and surgical exploration failled to demonstrate any space occupying lesion. After surgery the patients progressively recovered disapearing the neurological symptoms except for a slaight hemifacial spasm that remained in case 2. Clinical signs present in cerebello-pontine angle lesions and the occipito-cervical malformations are discussed. A possible mechanism to explain the association of both conditions is discussed.

  8. A STUDY OF THE INCID ENCE OF CEREBELLOPON TINE ANGLE TUMORS AND THEIR MAN AGEMENT IN A TERTIAR Y CARE HOSPITAL

    Directory of Open Access Journals (Sweden)

    Raja Sekhar Kennedy

    2015-04-01

    Full Text Available INTRODUCTI ON : Cerebellopontine angle tumors are a surgical challenge to many neurosurgeons who want to operate in this space. Although most of these tumors are benign, they are a challenge because of the complex anatomy and important neurovascular structures that traver se this space. Most common cerebellopontine angle tumor is vestibular schwannoma. The management of these cases is essentially surgical. There has been a change in the surgical strategy over the years from simple intratumoral decompression to complete micr osurgical excision, to facial nerve preservation and hearing preservation. AIMS AND OBJECTIVES: To study the clinical and radiological characteristics, know the pathological types and determine the surgical resectability and outcome of cerebellopontine ang le tumor. MATERIALS AND METHOD : It is a prospective study done in the department of Neurosurgery, King George Hospital, Visakhapatnam, Andhra Pradesh. It is a Tertiary Care Hospital. 50 patients diagnosed with cerebellopontine angle tumor were recruited in to the study and were managed. RESULTS : 50 cases of cerebellopontine angle tumors accounting for 11% of all intracranial space occupying lesions, of which vestibular schwannoma alone constituted 10%. Most of the tumors were large or giant tumors. Total resection was done in 74% of vestibular sch wannoma and 50% of meningiomas. Anatomical preservation of facial nerve was achieved in 67% of patients. CONCLUSION : C erebellopontine angle tumors show high incidence from 3 rd to 5 th decade with common symptoms being hearing loss and ataxia. Most of the pa tients presented at a delayed stage with large to giant tumors with no useful hearing. Complete excision of tumor preserving facial and lower cranial nerve function is the goal. Postoperative cerebrospinal fluid leak can be managed effectively with conserv ative therapy

  9. Adsorption of natural surfactants present in sea waters at surfaces of minerals: contact angle measurements

    Directory of Open Access Journals (Sweden)

    Katarzyna Boniewicz-Szmyt

    2009-09-01

    Full Text Available The wetting properties of solid mineral samples (by contact angles in original surfactant-containing sea water (Gulf of Gdańsk, Baltic were characterised under laboratory conditions on a large set (31 samples of well-classified stones of diverse hydrophobicity using the sessile drop (ADSA-P approach, captive bubble and inclined plate methods. An experimental relation between the static contact angle θeq and stone density ρ was obtained in the form θeq = Bρ + C, where B = 12.23 ± 0.92, C = - (19.17 ± 0.77, and r2 = 0.92. The histogram of θeq distribution for polished stone plates exhibited a multimodal feature indicating that the most abundant solid materials (hydrophilic in nature have contact angles θeq = 7.2, 10.7, 15.7 and 19.2º, which appear to be applicable to unspecified field stones as well. The contact angle, a pH-dependent quantity, appears to be a sensitive measure of stone grain size, e.g. granite. The captive bubble method gives reproducible results in studies of porous and highly hydrophilic surfaces such as stones and wood. The authors consider the adsorption of natural sea water surfactants on stone surfaces to be the process responsible for contact angle hysteresis. In the model, an equation was derived for determining the solid surface free energy from the liquid's surface tension γLV it also enabled the advancing θA and receding θR contact angles of this liquid to be calculated. Measurements of contact angle hysteresis Δθ (=θA - θR with surfactant-containing sea water and distilled water (reference on the same stone surfaces allowed the film pressure ΔΠ (1.22 to 8.80 mJ m-2, solid surface free energy ΔγS (-17.03 to -23.61 mJ m-2 and work done by spreading ΔWS (-1.23 to -11.52 mJ m-2 to be determined. The variability in these parameters is attributed to autophobing, an effect operative on a solid surface covered with an adsorptive layer of surfactants. The wetting behaviour of solid particles is of great

  10. A rare cause of infant facial paralysis: atypical teratoid rhabdoid tumour located in the cerebellopontine angle

    OpenAIRE

    Öztürk, Mehmet; Siğirci, Ahmet; Karadağ, Neşe

    2015-01-01

    Atypical teratoid rhabdoid tumour (ATRT) is a rare malignant tumour of the central nervous system with embryonal roots. The majority are seen in early childhood and location is often in the posterior fossa. Surgery, radiotherapy and chemotherapy are used in treatment. Knowledge of the localisation of the mass preoperatively is necessary for direction of the chemoradiotherapy and sufficient resection in surgery. Differentiation from other brain tumours is important because of poor prognosis an...

  11. Adsorption of natural surfactants present in sea waters at surfaces of minerals: contact angle measurements

    OpenAIRE

    Katarzyna Boniewicz-Szmyt; Pogorzelski, Stanisław J.; Adriana Mazurek

    2009-01-01

    The wetting properties of solid mineral samples (by contact angles) in original surfactant-containing sea water (Gulf of Gdańsk, Baltic) were characterised under laboratory conditions on a large set (31 samples) of well-classified stones of diverse hydrophobicity using the sessile drop (ADSA-P approach), captive bubble and inclined plate methods. An experimental relation between the static contact angle θeq and stone density ρ was obtained in the form θeq = Bρ + C, where B = 12.23 ± 0.92, C =...

  12. Phaco-endocycloplasty: A novel technique for management of ring iridociliary cyst presenting as acute angle closure

    Directory of Open Access Journals (Sweden)

    Vanita Pathak-Ray

    2016-01-01

    Full Text Available Iridociliary cysts of pigment epithelium are rare, ring cysts being rarer still, and usually benign in their clinical course. Presented here is a case of ring iridociliary cyst that resulted in secondary synechial angle closure with an acutely elevated intraocular pressure, refractory to medical treatment. Primary endocycloplasty and cataract extraction with implant were used successfully to manage the case.

  13. Adhesion of living cells revealed by variable-angle total internal reflection fluorescence microscopy (Conference Presentation)

    Science.gov (United States)

    Cardoso Dos Santos, Marcelina; Vézy, Cyrille; Jaffiol, Rodolphe

    2016-02-01

    Total Internal Reflection Fluorescence Microscopy (TIRFM) is a widespread technique to study cellular process occurring near the contact region with the glass substrate. In this field, determination of the accurate distance from the surface to the plasma membrane constitutes a crucial issue to investigate the physical basis of cellular adhesion process. However, quantitative interpretation of TIRF pictures regarding the distance z between a labeled membrane and the substrate is not trivial. Indeed, the contrast of TIRF images depends on several parameters more and less well known (local concentration of dyes, absorption cross section, angular emission pattern…). The strategy to get around this problem is to exploit a series of TIRF pictures recorded at different incident angles in evanescent regime. This technique called variable-angle TIRF microscopy (vaTIRFM), allowing to map the membrane-substrate separation distance with a nanometric resolution (10-20 nm). vaTIRFM was developed by Burmeister, Truskey and Reichert in the early 1990s with a prism-based TIRF setup [Journal of Microscopy 173, 39-51 (1994)]. We propose a more convenient prismless setup, which uses only a rotatable mirror to adjust precisely the laser beam on the back focal plane of the oil immersion objective (no azimuthal scanning is needed). The series of TIRF images permit us to calculate accurately membrane-surface distances in each pixel. We demonstrate that vaTIRFM are useful to quantify the adhesion of living cells for specific and unspecific membrane-surface interactions, achieved on various functionalized substrates with polymers (BSA, poly-L-lysin) or extracellular matrix proteins (collagen and fibronectin).

  14. Ductile deformation, boudinage and low angle normal faults. An overview of the structural variability at present-day rifted margins

    Science.gov (United States)

    Clerc, Camille; Jolivet, Laurent; Ringenbach, Jean-Claude; Ballard, Jean-François

    2016-04-01

    High quality industrial seismic profiles acquired along most of the world's passive margins present stunningly increased resolution that leads to unravel an unexpected variety of structures. An important benefit of the increased resolution of recent seismic profiles is that they provide an unprecedented access to the processes occurring in the middle and lower continental crust. We present a series of so far unreleased profiles that allow the identification of various rift-related geological processes such as crustal boudinage, ductile shear and low angle detachment faulting. The lower crust in passive margins appears much more intensely deformed than usually represented. At the foot of both magma-rich and magma-poor margins, we observe clear indications of ductile deformation of the deep continental crust along large-scale shallow dipping shear zones. These shear zones generally show a top-to-the-continent sense of shear consistent with the activity of overlying continentward dipping normal faults observed in the upper crust. This pattern is responsible for a migration of the deformation and associated sedimentation and/or volcanic activity toward the ocean. In some cases, low angle shear zones define an anastomosed pattern that delineates boudin-like structures. The interboudins areas seem to localize the maximum of deformation. The lower crust is intensely boudinaged and the geometry of those boudins seems to control the position and dip of upper crustal normal faults. We present some of the most striking examples (Uruguay, West Africa, Barents sea…) and discuss their implications for the time-temperature-subsidence history of the margins.

  15. Retromastoid-sub occipital: A novel approach to cerebello pontine angle in acoustic neuroma surgery-our experience in 21 cases

    Directory of Open Access Journals (Sweden)

    P K Nayak

    2011-01-01

    Full Text Available Background: Acoustic neuroma surgery poses significant challenges regarding definite management and preservation of hearing and the facial nerve are of great concern. Aim: To analyze the efficacy of the retromastoid approach in acoustic neuroma surgery. Materials and Methods: Tumors operated between January 2002 and December 2008, by the authors, using the retromastoid approach, were analyzed. Twenty-one patients who presented with acoustic tumor were considered for this study. Discussion: Precise knowledge of the neuroanatomy in the cerebellopontine angle is the key to success and microsurgical technique is the sole factor for good outcome. Conclusion: Retromastoid, in fact is the approach to the skull base with minimal or no damage to neurovascular structures, in contrast to the translabyrinthine or presigmoid approach.

  16. The Present Situation of Chattel Guarantee System and Its Improvements - Taking the Angl of American Uniform Commercial Code (UCC)

    Institute of Scientific and Technical Information of China (English)

    仇晓光; 刘聪

    2011-01-01

    Although there are appropriate stipulations for the chattel guarantees in the law of China,this guarantee system could not adapt to the request of economy's development because of the following reasons:the scope of chattel guarantees is narrow according to relevant stipulations; the transaction cost of the chattel is high; mortgage registration of chattel is in a mess; lack of efficiently executive guarantee system,etc.To counter the problems existing in the present Chinese chattel guarantee system,in this article,the author proposed some corresponding suggestions and countermeasures,hoping to perfect the chattel guarantee system in China.

  17. Value of blink reflex in assessing V and VII nerve function in patients with C. P. Angle tumours— a prospective study of 75 patients

    OpenAIRE

    Mahapatra, A. K.; A. K. Singh

    1997-01-01

    This propsective study analyses the role of blink reflex (BR) in 75 patients with Cerebellopontine Angle (CPA) tumours. The aim was to find out the subclinical involvement from the blink reflex findings. Fifth nerve was clinically involved in 82.7% patients while, BR was able to detect afferent abnormality only in 54% patients. The seventh nerve was clinically involved in 74.7% and blink reflex could detect the efferent abnormality is 72% patients. Thus, clinicoelectrophysiological correlatio...

  18. Ganglioneuroma of the Internal Auditory Canal Presenting as a Vestibular Schwannoma

    OpenAIRE

    Bekelis, Kimon; Meiklejohn, Duncan A; Missios, Symeon; Harris, Brent; Saunders, James E; Erkmen, Kadir

    2011-01-01

    In most series, 90% of cerebellopontine angle tumors are vestibular schwannomas. Meningiomas and epidermoid tumors follow with decreased frequency. Ganglioneuroma is a benign tumor usually found in the retroperitoneum and posterior mediastinum. We report a case of a 21-year-old man with gradual sensorineural hearing loss and a minimally enhancing lesion of the internal auditory canal, which was excised through a middle fossa approach and found histologically to be a ganglioneuroma. Like vesti...

  19. Presentation

    Directory of Open Access Journals (Sweden)

    Paulo Henrique Freire Vieira

    2013-12-01

    Full Text Available This dossier focuses on one of the essential debate topics today about the territorial dimension of the new development strategies concerned with the worsening of the global socioecological crisis, that is: the challenges related to the activation and integration in networks of localized agri-food systems. For its composition, some contributions presented and debated during the VI International Conference on Localized Agri-food System - The LAFS facing the opportunities and challenges of the new global context have been gathered. The event took place in the city of Florianópolis, from May 21th to 25th of 2013. The event was promoted by the Federal University of Santa Catarina (UFSC and by the Center for the International Cooperation on Agricultural Research for Development (CIRAD. Besides UFSC and CIRAD, EPAGRI, State University of Santa Catarina (UDESC, as well as research institutes and universities from other states (UFMG, IEA/SP, UFS, UFRGS and Mexican and Argentinian partners from the RED SIAL Latino Americana also participated in the organization of lectures, discussion tables and workshops.

  20. Presentation

    Directory of Open Access Journals (Sweden)

    Isidor Marí Mayans

    2004-04-01

    Full Text Available As was the case at the conference, "Humanities professions in the knowledge society", the Director of Humanities and Philology Studies at the UOC, Isidor Marí, presents this Dossier, and the subsequent virtual debate, with the aim of gaining useful conclusions, with specific repercussions on the organisation of the degree studies and its professional projection, especially at this time, which requires study plans to be redesigned in line with the Bologna process. In the author's opinion, we can only make the right operative decisions when we are able to understand the transformations taking place in the humanistic culture framed by the knowledge society, and to do so, debate has to be opened in which students, graduates, academics, researchers, professionals and analysts can all take part.In this article, Isidor Marí analyses the tensions and contradictions that arise when attempts are made to relate the concepts of the professional world, Humanities and the knowledge society. Firstly, neither are Humanities a profession nor the study of Humanities seen by students or society to be adaptable to the definition of professional profiles. However, this highlights an important paradox, as the culture economy, (and, thus, occupations in the cultural sector, is growing increasingly throughout western societies. Likewise, in terms of the relationship between Humanities and the knowledge society, the author describes and analyses how there currently coexist voices foreseeing the worst alongside those that see information and communications technologies opening the way for an enormously positive transformation in human civilisation and a new cultural era.

  1. Presentation

    Directory of Open Access Journals (Sweden)

    Eduardo Vicente

    2013-06-01

    Full Text Available In the present edition of Significação – Scientific Journal for Audiovisual Culture and in the others to follow something new is brought: the presence of thematic dossiers which are to be organized by invited scholars. The appointed subject for the very first one of them was Radio and the invited scholar, Eduardo Vicente, professor at the Graduate Course in Audiovisual and at the Postgraduate Program in Audiovisual Media and Processes of the School of Communication and Arts of the University of São Paulo (ECA-USP. Entitled Radio Beyond Borders the dossier gathers six articles and the intention of reuniting works on the perspectives of usage of such media as much as on the new possibilities of aesthetical experimenting being build up for it, especially considering the new digital technologies and technological convergences. It also intends to present works with original theoretical approach and original reflections able to reset the way we look at what is today already a centennial media. Having broadened the meaning of “beyond borders”, four foreign authors were invited to join the dossier. This is the first time they are being published in this country and so, in all cases, the articles where either written or translated into Portuguese.The dossier begins with “Radio is dead…Long live to the sound”, which is the transcription of a thought provoking lecture given by Armand Balsebre (Autonomous University of Barcelona – one of the most influential authors in the world on the Radio study field. It addresses the challenges such media is to face so that it can become “a new sound media, in the context of a new soundscape or sound-sphere, for the new listeners”. Andrew Dubber (Birmingham City University regarding the challenges posed by a Digital Era argues for a theoretical approach in radio studies which can consider a Media Ecology. The author understands the form and discourse of radio as a negotiation of affordances and

  2. Presentation

    Directory of Open Access Journals (Sweden)

    Nicanor Lopes

    2010-11-01

    Full Text Available The Journal Caminhando debuts with a new editorial format: eachmagazine will have a Dossier.In 2010 Christianity celebrated the centenary of Edinburgh. TheWorld Missionary Conference in Edinburgh in 1910 is regarded by manyas missiological watershed in the missionary and ecumenical movement.So the Faculty of Theology of the Methodist Church (FATEO decidedto organize a Wesleyan Week discussing the issue of mission. For anevent of this magnitude FATEO invited the Rev. Dr. Wesley Ariarajah,Methodist pastor and teacher of Sri Lanka with extensive experience inpastoral ministry in local churches and professor of History of Religionsand the New Testament at the Theological College of Lanka, maintainedby the Protestant Churches in Sri Lanka. In 1981 he was invited to jointhe World Council of Churches, where he presided for over ten years theCouncil of Interreligious Dialogue. From 1992 he served as Deputy GeneralSecretary of the WCC.The following texts are not the speeches of the Rev. Dr. WesleyAriarajah, for they will be published separately. Nevertheless, the journaldialogs with the celebrations of the centenary of Edinburgh, parting formthe intriguing theme: "Mission in the 21st century in Brazil". After all, howis it that mission takes place among us in personal, church, and communityactivities?Within the Dossier, as common to the journal, the textos are organizedas follows: Bible, Theology / History and Pastoral Care. Other items thatdo not fit within the Dossier, but, do articulate mission, can be found inthe section Declarations and Documents and Book Reviews.The authors of the Dossier have important considerations in buildinga contemporary missiological concept considering Brazilian reality.Anderson de Oliveira, in the Bible-Section, presents a significantexegeses of Matthew 26.6-13. What does it mean when Jesus is quotedwith the words: "For the poor always ye have with you, but me ye havenot always." Is this declaration challenging the gospels

  3. Incidental findings on MRI scans of patients presenting with audiovestibular symptoms

    Directory of Open Access Journals (Sweden)

    Khan Mohammad H

    2010-06-01

    Full Text Available Abstract Background The evaluation of patients presenting with audiovestibular symptoms usually includes MRI of the internal auditory meatus, the cerebellopontine angle and the brain. A significant percentage of these scans will present unexpected, incidental findings, which could have important clinical significance. Objective To determine the frequency and clinical significance of incidental findings on MRI scans of patients with audiovestibular symptoms. Materials and methods A retrospective analysis of 200 serial MRI scans. Results Gender distribution: equal. Age range: 17-82 years. One-hundred and four scans (52% were normal and 1 scan (0.5% demonstrated a unilateral vestibular schwannoma. Ninety-five scans (47.5% demonstrated incidental findings. Sixty-six of these (33% were considered of ishaemic origin and did not require further action. Five (2.5% scans demonstrated significant findings which warranted appropriate referral; Two Gliomas (1%, 2 cases of extensive White Matter Lesions (1%, 1 lipoma (0.5%. The remaining scans demonstrated various other findings. Conclusion Investigation of patients with audiovestibular symptoms with MRI scans revealed incidental findings in a significant percentage (47.5%. The majority of these findings were benign warranting no further action and only 2.5% required further referral. It is the responsibility of the referring Otolaryngologist to be aware of these findings, to be able to assess their significance, to inform the patient and if needed to refer for further evaluation.

  4. Reading Angles in Maps

    Science.gov (United States)

    Izard, Véronique; O'Donnell, Evan; Spelke, Elizabeth S.

    2014-01-01

    Preschool children can navigate by simple geometric maps of the environment, but the nature of the geometric relations they use in map reading remains unclear. Here, children were tested specifically on their sensitivity to angle. Forty-eight children (age 47:15-53:30 months) were presented with fragments of geometric maps, in which angle sections…

  5. [Bilateral cerebellopontine arachnoid cyst].

    Science.gov (United States)

    Gelabert-Gonzalez, M; Aran-Echabe, E; Pita-Buezas, L

    2016-06-16

    Introduccion. Los quistes aracnoideos bilaterales del angulo pontocerebeloso son excepcionales, y unicamente existen tres casos publicados en la bibliografia. Caso clinico. Niña de 14 años, previamente sana, que acude a consultas por presentar cefalea bifrontal de seis semanas de evolucion. La exploracion clinica era normal y la resonancia magnetica craneal mostraba dos lesiones extraaxiales localizadas en ambos angulos pontocerebelosos, siendo ligeramente mayor la izquierda. Las lesiones se comportaban como homogeneamente intensas en T1 e hiperintensas en T2, no captaban contraste y no existia restriccion en las secuencias de difusion. No se indico tratamiento quirurgico. Conclusiones. Los quistes aracnoideos bilaterales situados en el angulo pontocerebeloso son excepcionales. La principal indicacion para el tratamiento quirurgico es la presencia de sintomas o signos neurologicos coincidentes con la localizacion de los quistes.

  6. Comparative study cephalometric-radiographic of the cephalo-facio-dental patterns in patients who presented normal occlusion and class II, division 1 malocclusions, considering variations of the FMA angle

    International Nuclear Information System (INIS)

    The proposal of this job was to study cephalo-facio-dental patterns comparatively in patients who presented normal occlusion and Class II, division 1 malocclusions, considering variations of the FMA angle. The sample was composed of seventy-five telerradiographies on lateral pattern, obtained from Brazilian teenagers students of the ABC area (Santo Andre, Sao Bernardo do Campo and Sao Caetano do Sul), 'whites', who presented normal occlusion and Class II, division 1 malocclusions, without previous orthodontic treatment: their parents were Brazilian. (author)

  7. The Semiotic and Conceptual Genesis of Angle

    Science.gov (United States)

    Tanguay, Denis; Venant, Fabienne

    2016-01-01

    In the present study, we try to understand how students at the end of primary school conceive of angle: Is an angle a magnitude for them or a geometric figure, and how do they manage to coordinate the two aspects in their understanding of the concepts of angle and of angle measurement? With the aim of better grasping the way "angle" is…

  8. Concomitant occurrence of vestibular schwannoma and epidermoid tumor

    Directory of Open Access Journals (Sweden)

    B V Savitr Sastri

    2013-01-01

    Full Text Available The occurrence of two tumors adjacent to each other at the same site is very rare. We present here, a patient with a vestibular schwannoma found adjacent to an epidermoid tumor in the cerebellopontine angle.

  9. Cardiac syncope induced by glossopharyngeal "neuralgia": a rare presentation.

    Science.gov (United States)

    Korkes, Helio; de Oliveira, Eduardo Mesquita; Brollo, Luigi; Hachul, Denise Tessariol; Andrade, José Carlos da Silva; Peres, Mario Fernando Prieto; Schubsky, Victor

    2006-11-01

    The first description of severe pain in the distribution of the glossopharyngeal nerve is credited to Weisenberg, in 1910, in a patient with cerebellopontine angle tumor. However, it was Harris, in 1926, who coined the term glossopharyngeal neuralgia to describe this rare condition characterized by paroxysms of excruciating pain located laterally at the back of the tongue, soft palate, throat, and lateral and posterior pharynx, radiating to the ear. Swallowing, coughing, yawning or chewing may trigger pain, which usually lasts from seconds to minutes. The association between glossopharyngeal neuralgia and syncope is very rare, being identified by brief episodes of bradycardia, asystole, and hypotension. Such an association, with this same pathophysiology, was first described by Riley et al in 1942. PMID:17396191

  10. An Angle Criterion for Riesz Bases

    DEFF Research Database (Denmark)

    Lindner, Alexander M; Bittner, B.

    1999-01-01

    We present a characterization of Riesz bases in terms ofthe angles between certain finite dimensional subspaces. Correlationsbetween the bounds of the Riesz basis and the size of the angles arederived.......We present a characterization of Riesz bases in terms ofthe angles between certain finite dimensional subspaces. Correlationsbetween the bounds of the Riesz basis and the size of the angles arederived....

  11. Critical angle laser refractometer

    International Nuclear Information System (INIS)

    A simple laser refractometer based on the detection of the critical angle for liquids is presented. The calibrated refractometer presents up to 0.000 11 of uncertainty when the refractive index is in the range between 1.300 00 and 1.340 00. The experimental setup is easy to construct and the material needed is available at most optics laboratories. The calibration method is simple and can be used in other devices. The refractive index measurements in aqueous solutions of sodium chloride were carried out to test the device and a linear dependence between the refractive index and the salt concentration was found

  12. Perception of perspective angles

    NARCIS (Netherlands)

    Erkelens, C.J.

    2015-01-01

    We perceive perspective angles, that is, angles that have an orientation in depth, differently from what they are in physical space. Extreme examples are angles between rails of a railway line or between lane dividers of a long and straight road. In this study, subjects judged perspective angles bet

  13. Estudo cefalométrico das alturas faciais anterior e posterior, em crianças brasileiras, portadoras de má oclusão Classe I de Angle, na fase de dentadura mista Cephalometric study of the anterior and posterior facial heights in brazilian children, presenting Angle Class I malocclusion, in the mixed dentition

    Directory of Open Access Journals (Sweden)

    Arno Locks

    2005-04-01

    Full Text Available Realizou-se um estudo das alturas faciais anterior e posterior em 79 crianças brasileiras, sendo 46 do gênero feminino e 33 do masculino, com idades de 8 a 11 anos, portadoras de má oclusão Classe I de Angle, na fase de dentadura mista, não submetidas a tratamento ortodôntico. Esta investigação utilizou duas radiografias cefalométricas em norma lateral, de cada criança, com intervalo de 8 a 16 meses entre uma radiografia e outra, para comparação dos dados cefalométricos. Foram estudadas as proporções faciais anteriores, ou seja, a relação entre as dimensões N-Me (AFT, N-ENA (AFS, ENA-Me (AFI e o relacionamento entre as dimensões Ar-GO (AFP e a distância entre o plano palatino ao mento (AFA , isto é, o Índice da Altura Facial (IAF. Os resultados obtidos, possibilitaram constatar que as tendências de crescimento foram equilibradas em todas as situações estudadas; a dimensão altura facial inferior, contribuiu de forma mais significativa, nas alterações observadas na altura facial total; as proporções faciais anteriores se mantiveram em torno de 42% para a altura facial superior e 58% para a altura facial inferior; o índice da altura facial ou se manteve constante em torno de 0,66 ou apresentou uma tendência a aumentar com a idade; não ocorreu dimorfismo sexual com relação às proporções faciais e índice da altura facial.The objective of this study was to evaluate the anterior and posterior facial heights in 79 non orthodontic brazilian children, 46 females and 33 males, from 8 to 11 years old, presenting Angle Class I malocclusion, in the mixed dentition. Two lateral cephalometric radiographs were taken, with a time interval ranging from 8 to 16 months between radiographs in order to compare the cephalometric data. The anterior facial proportions were studied, based in following dimensions: N-Me (AFT, N-ENA (AFS e ENA-Me (AFI. The Facial Height Index (IAF was also evaluated taking in account the relationship

  14. The Q-angle and sport

    DEFF Research Database (Denmark)

    Hahn, Thomas; Foldspang, Anders

    1997-01-01

    Quadriceps muscle contraction tends to straighten the Q angle. We expected that sports comprising a high amount of quadriceps training could be associated with low Q angles. The aim of the present study was to estimate the Q angle in athletes and to investigate its potential associations...... with participation in sport. Three hundred and thirty-nine athletes had their Q angle measured. The mean of right-side Q angles was higher than left side, and the mean Q angle was higher in women than in men. The Q angle was positively associated with years of jogging, and negatively with years of soccer, swimming...... and sports participation at all. It is concluded that the use of Q angle measurements is questionable....

  15. A lattice determination of gA and left angle x right angle from overlap fermions

    International Nuclear Information System (INIS)

    We present results for the nucleon's axial charge gA and the first moment left angle x right angle of the unpolarized parton distribution function from a simulation of quenched overlap fermions. (orig.)

  16. Large angle measurement by interferometry

    Science.gov (United States)

    Apostol, Dan; Blanaru, Constantin; Damian, Victor S.; Logofatu, Petre-Catalin; Tumbar, R.; Dobroiu, Adrian

    1995-03-01

    An interferometric set-up able to measure angles as large as +180 degree(s) is presented. The principle of the method is to measure a linear displacement (translation) produced by a crank-gear mechanism which converts the angular movement of a rotating table. The optical scheme and consideration on the accuracy of the method are presented.

  17. Virtual reality in clinical teaching of cerebellopontine angle%浅谈虚拟现实在桥脑小脑角区临床教学中的应用

    Institute of Scientific and Technical Information of China (English)

    崔高宇; 冯华

    2010-01-01

    @@ 微创神经外科(minimally invasive neurosurgery)核心内容是在最大程度处理病变的同时要尽最大可能保护神经组织的结构和功能.因此要求对中枢神经系统的局部解剖学知识认识和掌握有很高的要求.

  18. Systematic variations in divergence angle

    CERN Document Server

    Okabe, Takuya

    2012-01-01

    Practical methods for quantitative analysis of radial and angular coordinates of leafy organs of vascular plants are presented and applied to published phyllotactic patterns of various real systems from young leaves on a shoot tip to florets on a flower head. The constancy of divergence angle is borne out with accuracy of less than a degree. It is shown that apparent fluctuations in divergence angle are in large part systematic variations caused by the invalid assumption of a fixed center and/or by secondary deformations, while random fluctuations are of minor importance.

  19. Angles as probabilities

    CERN Document Server

    Feldman, David V

    2008-01-01

    We use a probabilistic interpretation of solid angles to generalize the well-known fact that the inner angles of a triangle sum to 180 degrees. For the 3-dimensional case, we show that the sum of the solid inner vertex angles of a tetrahedron T, divided by 2*pi, gives the probability that an orthogonal projection of T onto a random 2-plane is a triangle. More generally, it is shown that the sum of the (solid) inner vertex angles of an n-simplex S, normalized by the area of the unit (n-1)-hemisphere, gives the probability that an orthogonal projection of S onto a random hyperplane is an (n-1)-simplex. Applications to more general polytopes are treated briefly, as is the related Perles-Shephard proof of the classical Gram-Euler relations.

  20. Phase angle measurement techniques

    Energy Technology Data Exchange (ETDEWEB)

    Madge, R.; Fischer, D.

    1996-01-01

    Real-time measure of the power transfer across a transmission line was discussed. Phase angle measurement techniques, algorithms and applications relevant to power utilities were assessed. Phase-based applications compute the voltage angle difference between two stations, thereby allowing for power transfer calculations and power system control applications. A list of phase angle measurement applications was provided. It includes frequency measurement, state estimation, adaptive relaying, power system control, system restoration, real power flow monitoring and stability assessment, reactive power requirements monitoring, HVDC modulation, subsynchronous resonance, sequence of event recording, and loss reduction and fault location. The optimum timing requirement was determined for each application. Among the timing systems available today, the Global Positioning System (GPS), supported by powerful computers and other custom hardware, is the only tool that can provide the accuracy and coverage needed by today`s power system applications. Commercially available equipment for phase angle measurements was also reviewed. 30 refs., 32 tabs., 5 figs.

  1. Small solid angle device setup and application

    International Nuclear Information System (INIS)

    To quantize the weight of Uranium-plate accurately, the small solid angle device was redesigned. To fit the requirement of homogeneity check, the sliding base was introduced in the design. This paper presents the detailed application of small solid angle device setup and quantization of Uranium-plate and homogeneity check. (authors)

  2. Angles in hyperbolic lattices

    DEFF Research Database (Denmark)

    Södergren, Carl Anders; Risager, Morten S.

    2015-01-01

    It is well known that the angles in a lattice acting on hyperbolic n -space become equidistributed. In this paper we determine a formula for the pair correlation density for angles in such hyperbolic lattices. Using this formula we determine, among other things, the asymptotic behavior...... of the density function in both the small and large variable limits. This extends earlier results by Boca, Pasol, Popa and Zaharescu and Kelmer and Kontorovich in dimension 2 to general dimension n . Our proofs use the decay of matrix coefficients together with a number of careful estimates, and lead...

  3. The quadriceps angle

    DEFF Research Database (Denmark)

    Miles, James Edward; Frederiksen, Jane V.; Jensen, Bente Rona;

    2012-01-01

    : Pelvic limbs from red foxes (Vulpes vulpes). METHODS: Q angles were measured on hip dysplasia (HD) and whole limb (WL) view radiographs of each limb between the acetabular rim, mid-point (Q1: patellar center, Q2: femoral trochlea), and tibial tuberosity. Errors of 0.5-2.0 mm at measurement landmarks...

  4. Aneurysmal Bone Cyst of the Skull Base in a 17-Year-Old Boy Who Was Referred with Unusual Presentation

    Directory of Open Access Journals (Sweden)

    Leila Aghaghazvini

    2011-05-01

    Full Text Available Aneurismal Bone Cyst (ABC is an osteolytic lesion"ncommonly observed in the first and second decades of"nlife more in females. They typically involve the long"nbones. Skull base involvement is rare. We describe"na 17-year-old boy with ABC of the skull base with"nforamen Jugular symptoms. Our case presented with a"nhistory of hoarseness for 2 years and facial asymmetry"nand left sided hearing loss from 5 months ago with no"nhistory of trauma or surgery. On physical examination,"nhe had left-sided sensorineural hearing loss with left"njugular foramen syndrome. The exam was otyherwise"nunremarkable. On MRI sequences an iso signal"nAbstracts"nIran J Radiol 2011, 8 (Supp.1 S61"nlobulated well defied mass containing few high signal"nareas in T1W and heterogeneous high signal (T2W"nand Flair was noted arising from the jugular foramen"nextending to the inferior cerebello-pontine angle"nwhich showed severe enhancement containing low"nsignal areas. No fluid-fluid level or enhancing septa was"nnoted. On CT scan a lytic expansile mass was detected"non the left side of foramen magnum and clivus with"ninvolvement of petrous apex and the internal auditory"ncanal. According to MRI findings, glomus jugular,"nschwannomas and meningiomas, but based on CT"nscan and MRI findings giant cell tumor and based on"nthe patient;s age ABC were our differential diagnosis."nThe lesion was only resected (without radiotherapy"nand histopathology confirmed an ABC. No recurrence"nwas observed after 6 months. Our case was interesting"nbecause of its rarity; not only the clinical jugular"nforamen syndrome but also the unusual radiological"npresentations such as severe enhancement, lack of"nfluid level and multi osseous involvement."nKeywords: Aneurysmal Bone Cyst, Foramen Jugular,"nPetros, Skull bBase, Clivus

  5. EMERGENCE ANGLE OF FLOW OVER AN AERATOR

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Aerator is an important device for release works of hydraulic structures with high-speed flow in order to protect them from cavitation damage. This kind of protecting effect is related closely to cavity length below the aerator, while the cavity length is dominated by the emergence angle over the aerator. Therefore it is crucial to determine this angle accurately. In the present paper the affecting intensities of flow depth and the fluctuating velocity on this angle were analyzed through two introduced parameters. Furthermore, the improved expressions of emergence angle estimation, for both ramp-type and step-type aerators, were presented by means of 68 sets of experimental data from 6 projects based on error theory. The results showed that the present method has higher accuracy than the previously reported methods.

  6. The lateral angle revisited

    DEFF Research Database (Denmark)

    Morgan, Jeannie; Lynnerup, Niels; Hoppa, R.D.

    2013-01-01

    measurements taken from computed tomography (CT) scans. Previous reports have observed that the lateral angle size in females is significantly larger than in males. The method was applied to an independent series of 77 postmortem CT scans (42 males, 35 females) to validate its accuracy and reliability...... method appears to be of minimal practical use in forensic anthropology and archeology. © 2013 American Academy of Forensic Sciences....

  7. Why are angles misperceived?

    OpenAIRE

    Nundy, Surajit; Lotto, Beau; Coppola, David; Shimpi, Amita; Purves, Dale

    2000-01-01

    Although it has long been apparent that observers tend to overestimate the magnitude of acute angles and underestimate obtuse ones, there is no consensus about why such distortions are seen. Geometrical modeling combined with psychophysical testing of human subjects indicates that these misperceptions are the result of an empirical strategy that resolves the inherent ambiguity of angular stimuli by generating percepts of the past significance of the stimulus rather than the geometry of its re...

  8. The role of radiology in the diagnosis and management of vestibular schwannoma

    Energy Technology Data Exchange (ETDEWEB)

    Sriskandan, N., E-mail: neshe@doctors.org.u [Department of Radiology, Guy' s and St Thomas' NHS Foundation Trust, London (United Kingdom); Connor, S.E.J. [Department of Radiology, Guy' s and St Thomas' NHS Foundation Trust, London (United Kingdom); Department of Neuroradiology, King' s College Hospital NHS Foundation Trust, London (United Kingdom)

    2011-04-15

    The most frequent lesion identified at the cerebellopontine angle cistern and internal auditory meatus (IAM) is the vestibular schwannoma. Radiological features, the role of imaging in screening and follow-up, therapeutic approaches and appearances following treatment will be discussed. Other cerebellopontine angle lesions will be illustrated and an algorithm presented to help in the imaging differential diagnosis. Whilst lesions other than vestibular schwannomas are rarely isolated to the IAM, the key clinical and radiological features that should raise the possibility of alternative neoplastic and inflammatory diseases will be highlighted.

  9. Wide Angle Effects in Future Galaxy Surveys

    OpenAIRE

    Yoo, Jaiyul; Seljak, Uros

    2013-01-01

    Current and future galaxy surveys cover a large fraction of the entire sky with a significant redshift range, and the recent theoretical development shows that general relativistic effects are present in galaxy clustering on very large scales. This trend has renewed interest in the wide-angle effect in galaxy clustering measurements, in which the distant-observer approximation is often adopted. Using the full wide-angle formula for computing the redshift-space correlation function, we show th...

  10. Modified Wide-angle Beam Propagation Method Using Douglas Operators①

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    A modified wide-angle beam propagation based on the Douglas operators is presented .The truncation error in the modified wide-angle beam propagation is reduced to o(△x)4in the transverse direction nearly without any increase of the computation time,whereas the error in the ordinary wide-angle beam propagation method is typically o(△x)2.With trivial programming changes,the accuracy is higher,especially in wide-angle propagation.

  11. Variable angle correlation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y K [Univ. of California, Berkeley, CA (United States)

    1994-05-01

    In this dissertation, a novel nuclear magnetic resonance (NMR) technique, variable angle correlation spectroscopy (VACSY) is described and demonstrated with {sup 13}C nuclei in rapidly rotating samples. These experiments focus on one of the basic problems in solid state NMR: how to extract the wealth of information contained in the anisotropic component of the NMR signal while still maintaining spectral resolution. Analysis of the anisotropic spectral patterns from poly-crystalline systems reveal information concerning molecular structure and dynamics, yet in all but the simplest of systems, the overlap of spectral patterns from chemically distinct sites renders the spectral analysis difficult if not impossible. One solution to this problem is to perform multi-dimensional experiments where the high-resolution, isotropic spectrum in one dimension is correlated with the anisotropic spectral patterns in the other dimensions. The VACSY technique incorporates the angle between the spinner axis and the static magnetic field as an experimental parameter that may be incremented during the course of the experiment to help correlate the isotropic and anisotropic components of the spectrum. The two-dimensional version of the VACSY experiments is used to extract the chemical shift anisotropy tensor values from multi-site organic molecules, study molecular dynamics in the intermediate time regime, and to examine the ordering properties of partially oriented samples. The VACSY technique is then extended to three-dimensional experiments to study slow molecular reorientations in a multi-site polymer system.

  12. Angle-deviation optical profilometer

    Institute of Scientific and Technical Information of China (English)

    Chen-Tai Tan; Yuan-Sheng Chan; Zhen-Chin Lin; Ming-Hung Chiu

    2011-01-01

    @@ We propose a new optical profilometer for three-dimensional (3D) surface profile measurement in real time.The deviation angle is based on geometrical optics and is proportional to the apex angle of a test plate.Measuring the reflectivity of a parallelogram prism allows detection of the deviation angle when the beam is incident at the nearby critical angle. The reflectivity is inversely proportional to the deviation angle and proportional to the apex angle and surface height. We use a charge-coupled device (CCD) camera at the image plane to capture the reflectivity profile and obtain the 3D surface profile directly.%We propose a new optical profilometer for three-dimensional (3D) surface profile measurement in real time.The deviation angle is based on geometrical optics and is proportional to the apex angle of a test plate.Measuring the refiectivity of a parallelogram prism allows detection of the deviation angle when the beam is incident at the nearby critical angle. The refiectivity is inversely proportional to the deviation angle and proportional to the apex angle and surface height. We use a charge-coupled device (CCD) camera at the image plane to capture the refiectivity profile and obtain the 3D surface profile directly.

  13. Absolute small-angle measurement based on optical feedback interferometry

    Institute of Scientific and Technical Information of China (English)

    Jingang Zhong; Xianhua Zhang; Zhixiang Ju

    2008-01-01

    We present a simple but effective method for small-angle measurement based on optical feedback inter-ferometry (or laser self-mixing interferometry). The absolute zero angle can be defined at the biggest fringe amplitude point, so this method can also achieve absolute angle measurement. In order to verify the method, we construct an angle measurement system. The Fourier-transform method is used to analysis the interference signal. Rotation angles are experimentally measured with a resolution of 10-6 rad and a measurement range of approximately from -0.0007 to +0.0007 rad.

  14. Small angle neutron scattering

    Directory of Open Access Journals (Sweden)

    Cousin Fabrice

    2015-01-01

    Full Text Available Small Angle Neutron Scattering (SANS is a technique that enables to probe the 3-D structure of materials on a typical size range lying from ∼ 1 nm up to ∼ a few 100 nm, the obtained information being statistically averaged on a sample whose volume is ∼ 1 cm3. This very rich technique enables to make a full structural characterization of a given object of nanometric dimensions (radius of gyration, shape, volume or mass, fractal dimension, specific area… through the determination of the form factor as well as the determination of the way objects are organized within in a continuous media, and therefore to describe interactions between them, through the determination of the structure factor. The specific properties of neutrons (possibility of tuning the scattering intensity by using the isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons make it particularly interesting in the fields of soft matter, biophysics, magnetic materials and metallurgy. In particular, the contrast variation methods allow to extract some informations that cannot be obtained by any other experimental techniques. This course is divided in two parts. The first one is devoted to the description of the principle of SANS: basics (formalism, coherent scattering/incoherent scattering, notion of elementary scatterer, form factor analysis (I(q→0, Guinier regime, intermediate regime, Porod regime, polydisperse system, structure factor analysis (2nd Virial coefficient, integral equations, characterization of aggregates, and contrast variation methods (how to create contrast in an homogeneous system, matching in ternary systems, extrapolation to zero concentration, Zero Averaged Contrast. It is illustrated by some representative examples. The second one describes the experimental aspects of SANS to guide user in its future experiments: description of SANS spectrometer, resolution of the spectrometer, optimization of

  15. Diffusion-weighted magnetic resonance imaging findings in a patient with trigeminal ganglineuroma

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seul Kee; Jeong, Min Young; Kang, Heoung Keun; Yoon, Woong [Dept. of Radiology, Chonnam National University Medical School, Chonnam National University Hospital, Gwangju (Korea, Republic of)

    2013-01-15

    A case of intracranial ganglioneuroma arising from the trigeminal nerve in the pontine and cerebellopontine angle cistern, in a 44-year-old female, is presented with an emphasis on diffusion-weighted imaging findings. We will discuss on how the tumor in the very unusual location should be differentiated particularly focused on diffusion-weighted imaging findings.

  16. Haemorrhagic acoustic neuroma with features of a vascular malformation. A case report

    Energy Technology Data Exchange (ETDEWEB)

    Benhaiem-Sigaux, N. [Dept. of Pathology, Hopital Henri Mondor, Creteil (France); Ricolfi, F. [Dept. of Neuroradiology, Henri Mondor Hospital, Creteil (France); Torres-Diaz, A.; Keravel, Y. [Dept. of Neurosurgery, Henri Mondo Hospital, Creteil (France); Poirier, J. [Dept. of Histology, Pitie-Salpetriere Hospital, Paris (France)

    1999-10-01

    A 55-year-old man with hearing loss presented with vertigo and vomiting. CT tomography and MRI demonstrated a cerebellopontine angle mass with foci of haemorrhage. An angiomatous tumour, with large abnormal veins adhering to the capsule, was completely removed. Histologically, the tumour was an acoustic neuroma with abnormal vascularisation and limited intratumoral haemorrhage. (orig.)

  17. Mixed solid and cystic acoustic neuroma: MR features and differential diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Denys, A. [Service de Neuroradiologie-CIERM Hopital de Bicetre, Univ. de Paris Sud, 78, 94 Kremlin-Bicetre (France); Duvoisin, B. [Service de Neuroradiologie-CIERM Hopital de Bicetre, Univ. de Paris Sud, 78, 94 Kremlin-Bicetre (France)]|[Dept. of Radiodiagnosis, University Hospital, Lausanne (Switzerland); Fernandes, J.G. [Service de Neuroradiologie-CIERM Hopital de Bicetre, Univ. de Paris Sud, 78, 94 Kremlin-Bicetre (France); Doyon, D. [Service de Neuroradiologie-CIERM Hopital de Bicetre, Univ. de Paris Sud, 78, 94 Kremlin-Bicetre (France)

    1991-11-01

    We present a very rare case of combined cystic and solid acoustic neuroma investigated by magnetic resonance imaging (MRI). This case illustrates the value of MRI in the characterization of tumours in the posterior cranial fossa, particularly acoustic neuromas, and its diagnostic impact in unusual situations. The differential diagnosis of cystic and mixed lesions in the cerebellopontine angle is discussed. (orig.)

  18. Wind Turbine Blade with Angled Girders

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention relates to a reinforced blade for a wind turbine, particularly to a blade having a new arrangement of two or more girders in the blade, wherein each of the girders is connected to the upper part and the lower part of the shell and forms an angle with another girder thereby...

  19. Bicycle helmet ventilation and comfort angle dependence.

    Science.gov (United States)

    Brühwiler, Paul A; Ducas, Charline; Huber, Roman; Bishop, Phillip A

    2004-09-01

    Five modern bicycle helmets were studied to elucidate some of the variations in ventilation performance, using both a heated manikin headform and human subjects (n = 7). Wind speed and head angle were varied to test their influence on the measured steady-state heat exchange (cooling power) in the skull section of the headform. The cooling power transmitted by the helmets varied from about 60% to over 90% of that of the nude headform, illustrating the range of present manufacturer designs. Angling the head forward by 30 degrees was found to provide better cooling power to the skull (up to 25%) for three of the helmets and almost equal cooling power in the remaining two cases. Comparisons of skull ventilation at these angles with human subjects strongly supported the headform results.

  20. Numerical aperture characteristics of angle-ended plastic optical fiber

    Science.gov (United States)

    Gao, Cheng; Farrell, Gerard

    2003-03-01

    With the increasing information rates demanded in consumer, automotive and aeronautical applications, a low cost and high performance physical transmission medium is required. Compared with Silica Optical Fiber, Plastic Optical Fiber (POF) offers an economic solution for a range of high-capacity, short-haul applications in industrial and military environments. Recently, a new type of POF, the perfluorinated graded-index plastic optical fiber (PF GI-POF), has been introduced that has low losses and high bandwidth at the communication wavelengths 850 nm and 1300nm. POF is normally terminated perpendicular to the fiber axis. We propose an angle-ended POF, which is terminated at non-perpendicular angles to the fiber axis. The aim of the research is to investigate the numerical aperture (NA) characteristics of angle-ended POF along the major axis of the elliptical endface. A theoretical model indicates that the NA of the angle-ended POF will increase nonlinearly with tilt-angle and the acceptance cone will be deflected with the angle of the deflection increasing nonlinearly with tilt-angle. We present results for the measured NA and the measured deflection angle using the far-field radiation method. Results are presented for 13 angle-ended SI-POF tilt-angles. We also present results for theoretical value of NA and deflection angle as a function of tilt-angle. The agreement between the measured and theoretical value is good up to tilt-angles of about 15 degrees, beyond which deviation occurs.

  1. Citalopram associated with acute angle-closure glaucoma: case report

    OpenAIRE

    Hassan Sabit; Thirumalai Srinivasa; Croos Robert; Davis Jane

    2005-01-01

    Abstract Background Acute angle-closure glaucoma is a rare complication in patients receiving anti-depressant treatment. In the following case, we report the development of acute angle closure glaucoma in a patient who overdosed on Citalopram, an antidepressant, and discuss the possible etiological mechanisms for the condition. Case presentation We report a 54 year old, Caucasian lady, with depression and alcohol dependence syndrome, who developed acute angle-closure glaucoma after an overdos...

  2. Foreign Body Embedded in Anterior Chamber Angle

    OpenAIRE

    Shmuel Graffi; Beatrice Tiosano; Ran Ben Cnaan; Jonathan Bahir; Modi Naftali

    2012-01-01

    Introduction. We present a case of a metallic foreign body embedded in the anterior chamber angle. After standing in close proximity to a construction worker breaking a tile, a 26-year-old woman using soft contact lens for the correction of mild myopia presented to emergency department for evaluation of a foreign body sensation of her right eye. Methods and Results. Diagnosis was confirmed by gonioscopic examination and a noncontrast CT scan of head and orbits. The foreign body was removed by...

  3. Two Comments on Bond Angles

    Science.gov (United States)

    Glaister, P.

    1997-09-01

    Tetrahedral Bond Angle from Elementary Trigonometry The alternative approach of using the scalar (or dot) product of vectors enables the determination of the bond angle in a tetrahedral molecule in a simple way. There is, of course, an even more straightforward derivation suitable for students who are unfamiliar with vectors, or products thereof, but who do know some elementary trigonometry. The starting point is the figure showing triangle OAB. The point O is the center of a cube, and A and B are at opposite corners of a face of that cube in which fits a regular tetrahedron. The required bond angle alpha = AÔB; and using Pythagoras' theorem, AB = 2(square root 2) is the diagonal of a face of the cube. Hence from right-angled triangle OEB, tan(alpha/2) = (square root 2) and therefore alpha = 2tan-1(square root 2) is approx. 109° 28' (see Fig. 1).

  4. Perturbative estimates of lepton mixing angles in unified models

    Energy Technology Data Exchange (ETDEWEB)

    Antusch, Stefan [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Foehringer Ring 6, 80805 Muenchen (Germany)], E-mail: antusch@mppmu.mpg.de; King, Stephen F. [School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Malinsky, Michal [Department of Theoretical Physics, School of Engineering Sciences, Royal Institute of Technology (KTH) - AlbaNova University Center, Roslagstullsbacken 21, SE-106 91 Stockholm (Sweden)

    2009-10-11

    Many unified models predict two large neutrino mixing angles, with the charged lepton mixing angles being small and quark-like, and the neutrino masses being hierarchical. Assuming this, we present simple approximate analytic formulae giving the lepton mixing angles in terms of the underlying high energy neutrino mixing angles together with small perturbations due to both charged lepton corrections and renormalisation group (RG) effects, including also the effects of third family canonical normalization (CN). We apply the perturbative formulae to the ubiquitous case of tri-bimaximal neutrino mixing at the unification scale, in order to predict the theoretical corrections to mixing angle predictions and sum rule relations, and give a general discussion of all limiting cases. We also discuss the implications for the sum rule relations of the measurement of a non-zero reactor angle, as hinted at by recent experimental measurements.

  5. Ischemia detection from morphological QRS angle changes.

    Science.gov (United States)

    Romero, Daniel; Martínez, Juan Pablo; Laguna, Pablo; Pueyo, Esther

    2016-07-01

    In this paper, an ischemia detector is presented based on the analysis of QRS-derived angles. The detector has been developed by modeling ischemic effects on the QRS angles as a gradual change with a certain transition time and assuming a Laplacian additive modeling error contaminating the angle series. Both standard and non-standard leads were used for analysis. Non-standard leads were obtained by applying the PCA technique over specific lead subsets to represent different potential locations of the ischemic zone. The performance of the proposed detector was tested over a population of 79 patients undergoing percutaneous coronary intervention in one of the major coronary arteries (LAD (n  =  25), RCA (n  =  16) and LCX (n  =  38)). The best detection performance, obtained for standard ECG leads, was achieved in the LAD group with values of sensitivity and specificity of [Formula: see text], [Formula: see text], followed by the RCA group with [Formula: see text], Sp  =  94.4 and the LCX group with [Formula: see text], [Formula: see text], notably outperforming detection based on the ST series in all cases, with the same detector structure. The timing of the detected ischemic events ranged from 30 s up to 150 s (mean  =  66.8 s) following the start of occlusion. We conclude that changes in the QRS angles can be used to detect acute myocardial ischemia. PMID:27243441

  6. The small angle diffractometer SANS at PSI

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-11-01

    With the start-up of SINQ an instrument for small angle neutron scattering will be operational which compares well with the world`s largest and most powerful facilities of this kind. Following the classical principle of the D11-instrument of ILL, it is equipped with state-of-the-art components as are nowadays available, including options for further upgrading. Great emphasis was laid upon providing a flexible, universal multi-user facility which guarantees a comfortable and reliable operation. In the present paper, the principle layout of the instrument is presented, and the individual components are described in detail. The paper concludes with model application of small angle scattering to a system of dilute CuCo alloys which undergo a phase separation under thermal treatment, forming spherical Co-precipitates dispersed in a Cu-rich matrix. (author) 3 figs., 1 tab., 14 refs.

  7. Off-Angle Iris Correction Methods

    Energy Technology Data Exchange (ETDEWEB)

    Santos-Villalobos, Hector J [ORNL; Thompson, Joseph T [ORNL; Karakaya, Mahmut [ORNL; Boehnen, Chris Bensing [ORNL

    2016-01-01

    In many real world iris recognition systems obtaining consistent frontal images is problematic do to inexperienced or uncooperative users, untrained operators, or distracting environments. As a result many collected images are unusable by modern iris matchers. In this chapter we present four methods for correcting off-angle iris images to appear frontal which makes them compatible with existing iris matchers. The methods include an affine correction, a retraced model of the human eye, measured displacements, and a genetic algorithm optimized correction. The affine correction represents a simple way to create an iris image that appears frontal but it does not account for refractive distortions of the cornea. The other method account for refraction. The retraced model simulates the optical properties of the cornea. The other two methods are data driven. The first uses optical flow to measure the displacements of the iris texture when compared to frontal images of the same subject. The second uses a genetic algorithm to learn a mapping that optimizes the Hamming Distance scores between off-angle and frontal images. In this paper we hypothesize that the biological model presented in our earlier work does not adequately account for all variations in eye anatomy and therefore the two data-driven approaches should yield better performance. Results are presented using the commercial VeriEye matcher that show that the genetic algorithm method clearly improves over prior work and makes iris recognition possible up to 50 degrees off-angle.

  8. Frequency scaling for angle gathers

    KAUST Repository

    Zuberi, M. A H

    2014-01-01

    Angle gathers provide an extra dimension to analyze the velocity after migration. Space-shift and time shift-imaging conditions are two methods used to obtain angle gathers, but both are reasonably expensive. By scaling the time-lag axis of the time-shifted images, the computational cost of the time shift imaging condition can be considerably reduced. In imaging and more so Full waveform inversion, frequencydomain Helmholtz solvers are used more often to solve for the wavefields than conventional time domain extrapolators. In such cases, we do not need to extend the image, instead we scale the frequency axis of the frequency domain image to obtain the angle gathers more efficiently. Application on synthetic data demonstrate such features.

  9. Angle independent velocity spectrum determination

    DEFF Research Database (Denmark)

    2014-01-01

    An ultrasound imaging system (100) includes a transducer array (102) that emits an ultrasound beam and produces at least one transverse pulse-echo field that oscillates in a direction transverse to the emitted ultrasound beam and that receive echoes produced in response thereto and a spectral vel...... velocity estimator (110) that determines a velocity spectrum for flowing structure, which flows at an angle of 90 degrees and flows at angles less than 90 degrees with respect to the emitted ultrasound beam, based on the received echoes....

  10. Dancing droplets: Contact angle, drag, and confinement

    Science.gov (United States)

    Benusiglio, Adrien; Cira, Nate; Prakash, Manu

    2015-11-01

    When deposited on a clean glass slide, a mixture of water and propylene glycol forms a droplet of given contact angle, when both pure liquids spread. (Cira, Benusiglio, Prakash: Nature, 2015). The droplet is stabilized by a gradient of surface tension due to evaporation that induces a Marangoni flow from the border to the apex of the droplets. The apparent contact angle of the droplets depends on both their composition and the external humidity as captured by simple models. These droplets present remarkable properties such as lack of a large pinning force. We discuss the drag on these droplets as a function of various parameters. We show theoretical and experimental results of how various confinement geometries change the vapor gradient and the dynamics of droplet attraction.

  11. Measurements of Neutrino Oscillation Angle theta_13

    CERN Document Server

    Kuze, Masahiro

    2013-01-01

    Neutrinos exhibit an interesting phenomenon called 'neutrino oscillation', in which a neutrino changes its flavor after traveling some flight length. Many experiments measured the mixing angles and mass differences, but the angle $\\theta_{13}$ had been unmeasured due to its smallness compared to others. During 2011 and 2012, series of new-generation neutrino experiments reported positive results in $\\theta_{13}$ search, and its value has been determined to be just below the previous upper limit. The non-zero result of $\\theta_{13}$ is a very good news for future of neutrino physics, since it opens a possibility of measuring the CP violation phase in the lepton sector. An introduction to neutrino oscillation and latest experimental results are presented. A detail is put on Double Chooz reactor experiment, in which the author is involved.

  12. Discovering the Inscribed Angle Theorem

    Science.gov (United States)

    Roscoe, Matt B.

    2012-01-01

    Learning to play tennis is difficult. It takes practice, but it also helps to have a coach--someone who gives tips and pointers but allows the freedom to play the game on one's own. Learning to act like a mathematician is a similar process. Students report that the process of proving the inscribed angle theorem is challenging and, at times,…

  13. Contactless angle detection using permalloy

    NARCIS (Netherlands)

    Eijkel, Kees J.; Rijk, Rolf

    1988-01-01

    An overview is given of measurements on angle detectors. The detectors consist of a pair of planar-Hall elements opposite to a rotatable magnet. The measurements are performed on a number of planar-Hall elements of different shape and size, and show good agreement with a previously described theoret

  14. Contact angles in the pseudopotential lattice Boltzmann modeling of wetting

    CERN Document Server

    Li, Q; Kang, Q J; Chen, Q

    2014-01-01

    In this paper, we aim to investigate the implementation of contact angles in the pseudopotential lattice Boltzmann modeling of wetting at a large density ratio. The pseudopotential lattice Boltzmann model [X. Shan and H. Chen, Phys. Rev. E 49, 2941 (1994)] is a popular mesoscopic model for simulating multiphase flows and interfacial dynamics. In this model, the contact angle is usually realized by a fluid-solid interaction. Two widely used fluid-solid interactions: the density-based interaction and the pseudopotential-based interaction, as well as a modified pseudopotential-based interaction formulated in the present paper, are numerically investigated and compared in terms of the achievable contact angles, the maximum and the minimum densities, and the spurious currents. It is found that the pseudopotential-based interaction works well for simulating small static (liquid) contact angles, however, is unable to reproduce static contact angles close to 180 degrees. Meanwhile, it is found that the proposed modif...

  15. A gallery approach for off-angle iris recognition

    Science.gov (United States)

    Karakaya, Mahmut; Yoldash, Rashiduddin; Boehnen, Christopher

    2015-05-01

    It has been proven that hamming distance score between frontal and off-angle iris images of same eye differs in iris recognition system. The distinction of hamming distance score is caused by many factors such as image acquisition angle, occlusion, pupil dilation, and limbus effect. In this paper, we first study the effect of the angle variations between iris plane and the image acquisition systems. We present how hamming distance changes for different off-angle iris images even if they are coming from the same iris. We observe that increment in acquisition angle of compared iris images causes the increment in hamming distance. Second, we propose a new technique in off-angle iris recognition system that includes creating a gallery of different off-angle iris images (such as, 0, 10, 20, 30, 40, and 50 degrees) and comparing each probe image with these gallery images. We will show the accuracy of the gallery approach for off-angle iris recognition.

  16. EVALUATION OF NECK SHAFT ANGLE OF FEMUR ON DRY BONES

    Directory of Open Access Journals (Sweden)

    Radha

    2015-04-01

    Full Text Available BACKGROUND: Evaluation of the neck shaft angle of femur helps to understand clinical relevance in bio mechanics of the hip joint. It helps for the better treatment of different pathological conditions of hip and femur and also to design prosthesis. Femoral neck shaft angle is important to convey the information regarding the race to which they belong. Hence the present study was under taken to determine the neck shaft angle of femur in humans. OBJECTIVE: 1. To correct the different types of deformity and to have a normal good walking Mechanism. 2. To know the recent methodology and attempt to evaluate the range of normal Angles of femora and their sex differences. METHODS: ANTHROPOMETRIC: 100 Adult dry bones were studied and analyzed . The neck shaft angle of femur was measured by tracing outlines of contours of all femora. RESULTS: The neck shaft angle of the femur have revealed that there is no much difference in between males and females. There was slightly higher 0.2° in females. INTERPRETATION & CONCLUSION: There was no significant gender difference in neck shaft angle. The Knowledge of knowing the neck shaft angle helps to understand the Biomechanics of the hip joint and also for better treatment of pathological condition of hip and femur.

  17. CATCHY PRESENTATIONS

    DEFF Research Database (Denmark)

    Eriksen, Kaare; Tollestrup, Christian; Ovesen, Nis

    2011-01-01

    An important competence for designers is the ability to communicate and present ideas and proposals for customers, partners, investors and colleagues. The Pecha Kucha principle, developed by Astrid Klein and Mark Dytham, has become a widely used and easy format for the presentation of new concepts...... and ideas in many areas and avoiding “Death by Powerpoint”. This paper discusses the need and tools for making short presentations and describes the result from a business development project where engineering graduate students in architecture and design used the Pecha Kucha format to present...

  18. Wide-angle electron detector

    International Nuclear Information System (INIS)

    The design, functioning, and main calibration, characteristics of a wide-angle detector, capable of recording electrons with energies >= 8 keV and insensitive to u.v. solar radiation are described. A description of the sensor (electron trap) and its electronics in the analog (DEGAFOC) and counting (DEGAFOI) modes is given. Examples of telemetry recordings, illustrating the operation of the detector are included. (Auth.)

  19. Gaia basic angle monitoring system

    Science.gov (United States)

    Gielesen, W.; de Bruijn, D.; van den Dool, T.; Kamphues, F.; Mekking, J.; Calvel, B.; Laborie, A.; Coatantiec, C.; Touzeau, S.; Erdmann, M.; Gare, P.; Monteiro, D.

    2013-09-01

    The Gaia mission1 will create an extraordinarily precise three-dimensional map of more than one billion stars in our Galaxy. The Gaia spacecraft2, built by EADS Astrium, is part of ESA's Cosmic Vision programme and scheduled for launch in 2013. Gaia measures the position, distance and motion of stars with an accuracy of 24 micro-arcsec using two telescopes at a fixed mutual angle of 106.5°, named the `Basic Angle', at an operational temperature of 100 K. This accuracy requires ultra-high stability at cryogenic conditions, which can only be achieved by using Silicon Carbide for both the optical bench and the telescopes. TNO has developed, built and space qualified the Silicon carbide Basic Angle Monitoring (BAM) on-board metrology system3 for this mission, measuring the relative motion of Gaia's telescopes with accuracies in the range of 0.5 micro-arcsec. This is achieved by a system of two laser interferometers able to detect Optical Path Differences (OPD) as small as 1.5 picometer rms. Following a general introduction on Gaia and the use of Silicon Carbide as base material this paper addresses the specific challenges towards the cryogenic application of the Gaia BAM including design, integration and verification/qualification by testing.

  20. LHC Report: playing with angles

    CERN Multimedia

    Mike Lamont for the LHC team

    2016-01-01

    Ready (after a machine development period), steady (running), go (for a special run)!   The crossing angles are an essential feature of the machine set-up. They have to be big enough to reduce the long-range beam-beam effect. The LHC has recently enjoyed a period of steady running and managed to set a new record for “Maximum Stable Luminosity Delivered in 7 days” of 3.29 fb-1 between 29 August and 4 September. The number of bunches per beam remains pegged at 2220 because of the limitations imposed by the SPS beam dump. The bunch population is also somewhat reduced due to outgassing near one of the injection kickers at point 8. Both limitations will be addressed during the year-end technical stop, opening the way for increased performance in 2017. On 10 and 11 September, a two day machine development (MD) period took place. The MD programme included a look at the possibility of reducing the crossing angle at the high-luminosity interaction points. The crossing angles are an ess...

  1. Information Presentation

    Science.gov (United States)

    Holden, Kritina L.; Thompson, Shelby G.; Sandor, Aniko; McCann, Robert S.; Kaiser, Mary K.; Adelstein, Barnard D.; Begault, Durand R.; Beutter, Brent R.; Stone, Leland S.; Godfroy, Martine

    2009-01-01

    The goal of the Information Presentation Directed Research Project (DRP) is to address design questions related to the presentation of information to the crew. In addition to addressing display design issues associated with information formatting, style, layout, and interaction, the Information Presentation DRP is also working toward understanding the effects of extreme environments encountered in space travel on information processing. Work is also in progress to refine human factors-based design tools, such as human performance modeling, that will supplement traditional design techniques and help ensure that optimal information design is accomplished in the most cost-efficient manner. The major areas of work, or subtasks, within the Information Presentation DRP for FY10 are: 1) Displays, 2) Controls, 3) Procedures and Fault Management, and 4) Human Performance Modeling. The poster will highlight completed and planned work for each subtask.

  2. Angle-action estimation in a general axisymmetric potential

    OpenAIRE

    Sanders, Jason

    2012-01-01

    The usefulness of angle-action variables in galaxy dynamics is well known, but their use is limited due to the difficulty of their calculation in realistic galaxy potentials. Here we present a method for estimating angle-action variables in a realistic Milky Way axisymmetric potential by locally fitting a St\\"ackel potential over the region an orbit probes. The quality of the method is assessed by comparison with other known methods for estimating angle-action variables of a range of disc and...

  3. A spin- and angle-resolving photoelectron spectrometer

    International Nuclear Information System (INIS)

    A new type of hemispherical electron energy analyzer that permits angle and spin resolved photoelectron spectroscopy has been developed. The analyzer permits standard angle resolved spectra to be recorded with a two-dimensional detector in parallel with spin detection using a mini-Mott polarimeter. General design considerations as well as technical solutions are discussed and test results from the Au(111) surface state are presented.

  4. Vehicle Sideslip Angle Estimation Based on Hybrid Kalman Filter

    OpenAIRE

    Li, Jing; Zhang, Jiaxu

    2016-01-01

    Vehicle sideslip angle is essential for active safety control systems. This paper presents a new hybrid Kalman filter to estimate vehicle sideslip angle based on the 3-DoF nonlinear vehicle dynamic model combined with Magic Formula tire model. The hybrid Kalman filter is realized by combining square-root cubature Kalman filter (SCKF), which has quick convergence and numerical stability, with square-root cubature based receding horizon Kalman FIR filter (SCRHKF), which has robustness against m...

  5. Lecture Presentations

    International Nuclear Information System (INIS)

    The Symposium on Physics of Elementary Interactions in the LHC Era held in Warsaw from 21 to 22 April 2008. The main subject of the workshop was to present the progress in CERN LHC collider project. Additionally some satellite activities in field of education, knowledge and technology transfer in the frame of CERN - Poland cooperation were shown

  6. Voting Present

    Directory of Open Access Journals (Sweden)

    James Lo

    2013-12-01

    Full Text Available During his time as a state senator in Illinois, Barack Obama voted “Present” 129 times, a deliberate act of nonvoting that subsequently became an important campaign issue during the 2008 presidential elections. In this article, I examine the use of Present votes in the Illinois state senate. I find evidence that Present votes can largely be characterized as protest votes used as a legislative tool by the minority party. Incorporating information from Present votes into a Bayesian polytomous item-response model, I find that this information increases the efficiency of ideal point estimates by approximately 35%. There is little evidence of significant moderation by Obama when Present votes are accounted for, though my results suggest that Obama’s voting record may have moderated significantly before his subsequent election to the U.S. Senate. My results also suggest that because legislative nonvoting may occur for a variety of reasons, naive inclusion of nonvoting behavior into vote choice models may lead to biased results.

  7. Ocular Biometry in Angle Closure

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Razeghinejad

    2013-01-01

    Full Text Available Purpose: To compare ocular biometric parameters in primary angle closure suspects (PACS, primary angle closure glaucoma (PACG and acute primary angle closure (APAC. Methods: This cross-sectional study was performed on 113 patients including 33 cases of PACS, 45 patients with PACG and 35 subjects with APAC. Central corneal thickness (CCT, axial length (AL, anterior chamber depth (ACD and lens thickness (LT were measured with an ultrasonic biometer. Lens-axial length factor (LAF, relative lens position, corrected ACD (CACD and corrected lens position were calculated. The parameters were measured bilaterally but only data from the right eyes were compared. In the APAC group, biometric parameters were also compared between affected and unaffected fellow eyes. Logistic regression analysis was performed to identify risk factors. Results: No statistically significant difference was observed in biometric parameters between PACS and PACG eyes, or between affected and fellow eyes in the APAC group (P>0.05 for all comparisons. However, eyes with APAC had thicker cornea (P=0.001, thicker lens (P<0.0001, shallower ACD (P=0.009, shallower CACD (P=0.003 and larger LAF (P<0.0001. Based on ROC curve analysis, lower ACD, and larger LT, LAF and CCT values were associated with APAC. In the APAC group, LAF (P<0.0001 and CCT (P=0.001 were significant risk factors. Conclusion: This study revealed no significant difference in biometric characteristics in eyes with PACS and PACG. However, larger LAF and CCT were predictive of APAC.

  8. Going round the bend: Persistent personal biases in walked angles.

    Science.gov (United States)

    Jetzschke, Simon; Ernst, Marc O; Moscatelli, Alessandro; Boeddeker, Norbert

    2016-03-23

    For navigation through our environment, we can rely on information from various modalities, such as vision and audition. This information enables us for example to estimate our position relative to the starting position, or to integrate velocity and acceleration signals from the vestibular organ and proprioception to estimate the displacement due to self-motion. To better understand the mechanisms that underlie human navigation we analysed the performance of participants in an angle-walking task in the absence of visual and auditory signals. To this end, we guided them along paths of different lengths and asked them to turn by an angle of ±90°. We found significant biases in turn angles, i.e. systematic deviations from the correct angle and that these were characteristic for individual participants. Varying path length, however, had little effect on turn accuracy and precision. To check whether this idiosyncrasy was persistent over time and present in another type of walking task, we performed a second experiment several weeks later. Here, the same participants were guided to walk angles with varying amplitude. We then asked them to judge whether they had walked an angle larger or smaller than 90° in a two-alternative forced-choice paradigm. The personal bias was highly correlated between the two experiments even though they were conducted weeks apart. The presence of a persistent bias in walked angles in the absence of external directional cues indicates a possible error component for navigation, which is surprisingly time stable and idiosyncratic. PMID:26854843

  9. Operational multi-angle hyperspectral remote sensing for feature detection

    Science.gov (United States)

    Bostater, Charles R.; Brooks, Donald K.

    2013-10-01

    Remote sensing results of land and water surfaces from airborne and satellite platforms are dependent upon the illumination geometry and the sensor viewing geometry. Correction of pushbroom hyperspectral imagery can be achieved using bidirectional reflectance factors (BRF's) image features based upon their multi-angle hyperspectral signatures. Ground validation of features and targets utilize non-imaging sensors such as hemispherical goniometers. In this paper, a new linear translation based hyperspectral imaging goniometer system is described. Imagery and hyperspectral signatures obtained from a rotation stage platform and the new linear non-hemispherical goniometer system shows applications and a multi-angle correction approach for multi-angle hyperspectral pushbroom imagery corrections. Results are presented in a manner in order to describe how ground, vessel and airborne based multi-angle hyperspectral signatures can be applied to operational hyperspectral image acquisition by the calculation of hyperspectral anisotropic signature imagery. The results demonstrate the analysis framework from the systems to water and coastal vegetation for exploitation of surface and subsurface feature or target detection based using the multi-angle radiative transfer based BRF's. The hyperspectral pushbroom multi-angle analysis methodology forms a basis for future multi-sensor based multi-angle change detection algorithms.

  10. Opening Angles of Collapsar Jets

    OpenAIRE

    Mizuta, Akira; Ioka, Kunihito

    2013-01-01

    We investigate the jet propagation and breakout from the stellar progenitor for gamma-ray burst (GRB) collapsars by performing two-dimensional relativistic hydrodynamic simulations and analytical modeling. We find that the jet opening angle is given by $\\theta_j \\sim 1/5 \\Gamma_{0}$, and infer the initial Lorentz factor of the jet at the central engine, $\\Gamma_0$, is a few for existing observations of $\\theta_j$. The jet keeps the Lorentz factor low inside the star by converging cylindricall...

  11. Small angle scattering and polymers

    Energy Technology Data Exchange (ETDEWEB)

    Cotton, J.P. [Laboratoire Leon Brillouin (LLB) - Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)

    1996-12-31

    The determination of polymer structure is a problem of interest for both statistical physics and industrial applications. The average polymer structure is defined. Then, it is shown why small angle scattering, associated with isotopic substitution, is very well suited to the measurement of the chain conformation. The corresponding example is the old, but pedagogic, measurement of the chain form factor in the polymer melt. The powerful contrast variation method is illustrated by a recent determination of the concentration profile of a polymer interface. (author) 12 figs., 48 refs.

  12. Technical presentation

    CERN Multimedia

    FI Department

    2008-01-01

    RADIOSPARES, the leading catalogue distributor of components (electronic, electrical, automation, etc.) and industrial supplies will be at CERN on Friday 3 October 2008 (Main Building, Room B, from 9.00 a.m. to 3.00 p.m.) to introduce its new 2008/2009 catalogue. This will be the opportunity for us to present our complete range of products in more detail: 400 000 part numbers available on our web site (Radiospares France, RS International, extended range of components from other manufacturers); our new services: quotations, search for products not included in the catalogue, SBP products (Small Batch Production: packaging in quantities adapted to customers’ requirements); partnership with our focus manufacturers; demonstration of the on-line purchasing tool implemented on our web site in conjunction with CERN. RADIOSPARES will be accompanied by representatives of FLUKE and TYCO ELECTRONICS, who will make presentations, demonstrate materials and answer any technical questio...

  13. Overview Presentation

    Science.gov (United States)

    Lytle, John

    2001-01-01

    This report provides an overview presentation of the 2000 NPSS (Numerical Propulsion System Simulation) Review and Planning Meeting. Topics include: 1) a background of the program; 2) 1999 Industry Feedback; 3) FY00 Status, including resource distribution and major accomplishments; 4) FY01 Major Milestones; and 5) Future direction for the program. Specifically, simulation environment/production software and NPSS CORBA Security Development are discussed.

  14. Device for Measuring Landslide Critical Angle

    Institute of Scientific and Technical Information of China (English)

    Li Xueling; Xia Weisheng; Huang Daoyou; Yu Yun

    2016-01-01

    The mountain landslide has high destructive effects, discussion of its landslide critical angle has always been one of the major concerns, and we designed a system that can automatically measure the landslide critical angle. This equipment consists of the

  15. Technical presentation

    CERN Multimedia

    FP Department

    2009-01-01

    07 April 2009 Technical presentation by Leuze Electronics: 14.00 – 15.00, Main Building, Room 61-1-017 (Room A) Photoelectric sensors, data identification and transmission systems, image processing systems. We at Leuze Electronics are "the sensor people": we have been specialising in optoelectronic sensors and safety technology for accident prevention for over 40 years. Our dedicated staff are all highly customer oriented. Customers of Leuze Electronics can always rely on one thing – on us! •\tFounded in 1963 •\t740 employees •\t115 MEUR turnover •\t20 subsidiaries •\t3 production facilities in southern Germany Product groups: •\tPhotoelectric sensors •\tIdentification and measurements •\tSafety devices

  16. SMALL ANGLE CRAB COMPENSATION FOR LHC IR UPGRADE

    Energy Technology Data Exchange (ETDEWEB)

    CALAGA,R.; DORDA, U.; OHMI, D.; OIDE, K.; TOMAS, R.; ZIMMERMANN, F.

    2007-06-25

    A small angle (< 1 mrad) crab scheme is an attractive option for the LHC luminosity upgrade to recover the geometric luminosity loss from the finite crossing angle [I]. The luminosity loss increases steeply to unacceptable levels as the IP beta function is reduced below its nominal value (see Fig. 1 in Ref. [2]). The crab compensation in the LHC can be accomplished using only two sets of deflecting RF cavities, placed in collision-free straight sections of the LHC to nullify the effective crossing angles at IPI & IP5. We also explore a 400 MHz superconducting cavity design and discuss the pertinent RF challenges. We present IR optics configurations with low-angle crab crossing, study the beam-beam performance and proton-beam emittance growth in the presence of crab compensation, lattice errors, and crab RF noise sources.

  17. First statistics of the isopistonic angle for long baseline interferometry

    Science.gov (United States)

    Ziad, A.; Elhalkouj, T.; Petrov, R. G.; Borgnino, J.; Lazrek, M.; Benkhaldoun, Z.; Martin, F.; Elazhari, Y.

    2016-06-01

    To reach a suitable limiting magnitude with a multi-aperture interferometer, we need to cophase the different telescopes using a reference source. The latter should be located in the same isopistonic domain as the science source. We developed a direct analytical expression of deducing the isopistonic angle from atmospheric optical parameters as seeing, isoplanatic angle and outer scale. All of these atmospheric turbulence parameters are measured by the Generalized Seeing Monitor (GSM). The first statistics of the isopistonic angle obtained from the GSM data are presented and comparison between the major sites over the world are discussed (La Silla, Cerro Pachon, Paranal, San Pedro, Mt Palomar, Mauna Kea, La Palma, Oukaïmeden, Maydanak, Dome C). Implications of these isopistonic angle statistics on large interferometers cophasing in terms of sky coverage and limiting magnitude are discussed.

  18. Flow tilt angles near forest edges - Part 1: Sonic anemometry

    DEFF Research Database (Denmark)

    Dellwik, Ebba; Mann, Jakob; Larsen, Klaus Steenberg

    2010-01-01

    An analysis of flow tilt angles from a fetch-limited beech forest site with clearings is presented in the context of vertical advection of carbon dioxide. Flow angles and vertical velocities from two sonic anemometers by different manufacturers were analyzed. Instead of using rotations, where zero......-flow angles were assumed for neutral flow, the data was interpreted in relation to upstream and downstream forest edges. Uncertainties caused by flow distortion, vertical misalignment and limited sampling time (statistical uncertainty) were evaluated and found to be highly significant. Since the attack angle...... distribution of the wind on the sonic anemometer is a function of atmospheric stratification, an instrumental error caused by imperfect flow distortion correction is also a function of the atmospheric stratification. In addition, it is discussed that the sonic anemometers have temperature dependent off...

  19. The qualitative criterion of transient angle stability

    OpenAIRE

    Lyu, R; Xue, Y.; Xue, F; Wu, Qiuwei; Yang, Guangya; Zhou, H; Ju, P.

    2015-01-01

    In almost all the literatures, the qualitative assessment of transient angle stability extracts the angle information of generators based on the swing curve. As the angle (or angle difference) of concern and the threshold value rely strongly on the engineering experience, the validity and robust of these criterions are weak. Based on the stability mechanism from the extended equal area criterion (EEAC) theory and combining with abundant simulations of real system, this paper analyzes the crit...

  20. 30 CFR 56.19037 - Fleet angles.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Fleet angles. 56.19037 Section 56.19037 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Sheaves § 56.19037 Fleet angles. Fleet angles on hoists installed after November 15, 1979, shall not...

  1. 30 CFR 57.19037 - Fleet angles.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Fleet angles. 57.19037 Section 57.19037 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Sheaves § 57.19037 Fleet angles. Fleet angles on hoists installed after November 15, 1979, shall not...

  2. Foreign Body Embedded in Anterior Chamber Angle

    Directory of Open Access Journals (Sweden)

    Shmuel Graffi

    2012-01-01

    Full Text Available Introduction. We present a case of a metallic foreign body embedded in the anterior chamber angle. After standing in close proximity to a construction worker breaking a tile, a 26-year-old woman using soft contact lens for the correction of mild myopia presented to emergency department for evaluation of a foreign body sensation of her right eye. Methods and Results. Diagnosis was confirmed by gonioscopic examination and a noncontrast CT scan of head and orbits. The foreign body was removed by an external approach without utilizing a magnet. The patient's final outcome was favorable. Discussion. The above is a rare clinical situation, which is impossible to detect on slit-lamp examination without a gonioscopic view. Proper imaging and a specific management are mandatory in order to achieve favorable outcome.

  3. High-resolution NMR of anisotropic samples with spinning away from the magic angle

    Energy Technology Data Exchange (ETDEWEB)

    Sakellariou, Dimitris; Meriles, Carlos A.; Martin, Rachel W.; Pines, Alexander

    2003-03-31

    High-resolution NMR of samples in the solid state is typically performed under mechanical sample spinning around an axis that makes an angle, called the magic angle, of 54.7 degrees with the static magnetic field. There are many cases in which geometrical and engineering constraints prevent spinning at this specific angle. Implementations of in-situ and ex-situ magic angle field spinning might be extremely demanding because of the power requirements or an inconvenient sample size or geometry. Here we present a methodology based on switched angle spinning between two angles, none of which is the magic angle, which provide both isotropic and anisotropic information. Using this method, named Projected Magic Angle Spinning, we were able to obtain resolved isotropic chemical shifts in spinning samples where the broadening is mostly inhomogeneous.

  4. Small Angle Crab Compensation for LHC IR Upgrade

    CERN Document Server

    Akai, K; Dorda, U; Ohmi, K; Oide, K; Tomás, R; Zimmermann, T

    2007-01-01

    A small angle crab scheme is being considered for the LHC luminosity upgrade. In this paper we present a 400MHz superconducting cavity design and discuss the pertinent RF challenges. We also present a study on the beam-beam performance and proton-beam emittance growth in the presence of crab compensation, with RF noise sources.

  5. Determination of the Contact Angle Based on the Casimir Effect

    Science.gov (United States)

    Mazuruk, K.; Volz, M. P.

    2015-01-01

    In several crystal growth processed based on capillarity, a melt comes into contact with a crucible wall at an angle defined as the contact angle. For molten metals and semiconductors, this contact angle is dependent upon both the crucible and melt material and typical values fall in the range 80-170deg. However, on a microscopic scale, there does not exist a precise and sharp contact angle but rather the melt and solid surfaces merge smoothly and continuously over a distance of up to several micrometers. Accurate modeling requires a more advanced treatment of this interaction. The interaction between the melt and solid surfaces can be calculated by considering two forces: a short-range repulsive force and a longer range (up to a few micrometers) Casimir force. The Casimir force between the two bodies of complex geometry is calculated using a retarded temperature Green's function (Matsubara type) for the photon in the medium. The governing equations are cast in the form of a set of boundary integral equations which are then solved numerically for the case of molten Ge on SiO2. The shape of the molten surface approaching the flat solid body is determined, and the contact angle is defined as the angle between the two surfaces at the microscopically asymptotic distance of 1-2 micrometers. The formulation of this model and the results of the numerical calculations will be presented and discussed.

  6. Orientation angle rotatability of planar serial n-link manipulators

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This paper presents a new method of analyzing the orientation angle rotatability of a planar serial n-link manipulator by examining the rotatability of its virtual equivalent mechanism.Workspace orientation boundary region decomposition is proposed based on the polynomial discriminant derived from a serial three-link manipulator.Orientation angle workspace indicates a set of angle ranges by which the end-effector can reach with certain orientation for every point in the reachable position workspace.By introducing a virtual equivalent mechanism,the open-chain kinematic problem is converted into a close-chain mechanism,and the Grashof-type condition is used to examine the rotatability of the end-effector link.The reachable position workspace can be divided into several Grashof intervals and non-Grashof intervals based on the extreme positions and singular configurations of a manipulator.The derived equations in this paper can be used to calculate the variation rule of the orientation angle workspace of any given planar serial n-link manipulator on the basis of its link parameters.The orientation angle rotatability of a seven-link serial manipulator is solved by the proposed method and graphical representations of the orientation angle workspaces are mapped onto a three-dimensional coordinate system.The theoretical approach has practical significance for the design of a highly dexterous serial n-link manipulator with proposed link relations.

  7. Limbus Impact on Off-angle Iris Degradation

    Energy Technology Data Exchange (ETDEWEB)

    Karakaya, Mahmut [ORNL; Barstow, Del R [ORNL; Santos-Villalobos, Hector J [ORNL; Thompson, Joseph W [ORNL; Bolme, David S [ORNL; Boehnen, Chris Bensing [ORNL

    2013-01-01

    The accuracy of iris recognition depends on the quality of data capture and is negatively affected by several factors such as angle, occlusion, and dilation. Off-angle iris recognition is a new research focus in biometrics that tries to address several issues including corneal refraction, complex 3D iris texture, and blur. In this paper, we present an additional significant challenge that degrades the performance of the off-angle iris recognition systems, called the limbus effect . The limbus is the region at the border of the cornea where the cornea joins the sclera. The limbus is a semitransparent tissue that occludes a side portion of the iris plane. The amount of occluded iris texture on the side nearest the camera increases as the image acquisition angle increases. Without considering the role of the limbus effect, it is difficult to design an accurate off-angle iris recognition system. To the best of our knowledge, this is the first work that investigates the limbus effect in detail from a biometrics perspective. Based on results from real images and simulated experiments with real iris texture, the limbus effect increases the hamming distance score between frontal and off-angle iris images ranging from 0.05 to 0.2 depending upon the limbus height.

  8. Small angle electron diffraction and deflection

    Directory of Open Access Journals (Sweden)

    T. Koyama

    2012-03-01

    Full Text Available Electron optical system is constructed in order to obtain small angle diffraction and Lorentz deflection of electrons at the order of down to 10-6 radian in the reciprocal space. Long-distance camera length up to 3000 m is achieved in a conventional transmission electron microscope with LaB6 thermal emission type. The diffraction pattern at 5 × 10-6 radian is presented in a carbon replica grating with 500 nm lattice spacing while the magnetic deflection pattern at 2 × 10-5 radian is exhibited in Permalloy elements. A simultaneous recording of electron diffraction and Lorentz deflection is also demonstrated in 180 degree striped magnetic domains of La0.825Sr0.175MnO3.

  9. Neutrino Mixing Angles in Sequential Dominance to NLO and NNLO

    CERN Document Server

    Antusch, S; King, S F

    2010-01-01

    Neutrinos with hierarchical masses and two large mixing angles may naturally originate from sequential dominance (SD). Within this framework we present analytic expressions for the neutrino mixing angles including the next-to-leading order (NLO) and next-to-next-to-leading order (NNLO) corrections arising from the second lightest and lightest neutrino masses. The analytic results for neutrino mixing angles in SD presented here, including the NLO and NNLO corrections, are applicable to a wide class of models and may provide useful insights when confronting the models with data from high precision neutrino experiments. We also point out that for special cases of SD corresponding to form dominance (FD) the NLO and NNLO corrections both vanish. For example we study tri-bimaximal (TB) mixing via constrained sequential dominance (CSD) which involves only a NNLO correction and tri-bimaximal-reactor (TBR) mixing via partially constrained sequential dominance (PCSD) which involves a NLO correction suppressed by the sm...

  10. Automated measurement of diagnostic angles for hip dysplasia

    Science.gov (United States)

    de Raedt, Sepp; Mechlenburg, Inger; Stilling, Maiken; Rømer, Lone; Søballe, Kjeld; de Bruijne, Marleen

    2013-03-01

    A fully automatic method for measuring diagnostic angles of hip dysplasia is presented. The method consists of the automatic segmentation of CT images and detection of anatomical landmarks on the femur and acetabulum. The standard angles used in the diagnosis of hip dysplasia are subsequently automatically calculated. Previous work in automating the measuring of angles required the manual segmentation or delineation of the articular joint surface. In the current work automatic segmentation is established using graph-cuts with a cost function based on a sheetness score to detect the sheet-like structure of the bone. Anatomical landmarks are subsequently detected using heuristics based on ray-tracing and the distance to the approximated acetabulur joint surface. Standard diagnositic angles are finally calculated and presented for interpretation. Experiments using 26 patients, showed a good agreement with gold standard manual measurements by an expert radiologist as performed in daily practice. The mean difference for the five angles was between -1:1 and 2:0 degrees with a concordance correlation coefficient between 0:87 and 0:93. The standard deviation varied between 2:3 and 4:1 degrees. These values correspond to values found in evaluating interobserver and intraobserver variation for manual measurements. The method can be used in clinical practice to replace the current manual measurements performed by radiologists. In the future, the method will be integrated into an intraoperative surgical guidance system.

  11. Caustic graphene plasmons with Kelvin angle

    CERN Document Server

    Shi, Xihang; Gao, Fei; Xu, Hongyi; Yang, Zhaoju; Zhang, Baile

    2015-01-01

    A century-long argument made by Lord Kelvin that all swimming objects have an effective Mach number of 3, corresponding to the Kelvin angle of 19.5 degree for ship waves, has been recently challenged with the conclusion that the Kelvin angle should gradually transit to the Mach angle as the ship velocity increases. Here we show that a similar phenomenon can happen for graphene plasmons. By analyzing the caustic wave pattern of graphene plasmons stimulated by a swift charged particle moving uniformly above graphene, we show that at low velocities of the charged particle, the caustics of graphene plasmons form the Kelvin angle. At large velocities of the particle, the caustics disappear and the effective semi-angle of the wave pattern approaches the Mach angle. Our study introduces caustic wave theory to the field of graphene plasmonics, and reveals a novel physical picture of graphene plasmon excitation during electron energy-loss spectroscopy measurement.

  12. Best Angle to Orient Two Intersecting Lines

    Energy Technology Data Exchange (ETDEWEB)

    Awwal, A S; Ferguson, S W; Shull, P B

    2006-07-25

    Fiducials in the form of intersecting straight lines are used to align the target in the final target chamber of the National Ignition Facility of Lawrence Livermore National Laboratory. One of the techniques used to locate these lines is the Hough transform. When two lines intersect at a 90 degree angle, it is tempting to orient the lines to horizontal and vertical directions. There are other possible angles at which the lines may be oriented. One question that arises while designing the fiducials is whether there is a preferred angle or range of angles that leads to higher accuracy. This work attempts to answer this question through detailed computer simulation.

  13. Behavior of Tilted Angle Shear Connectors.

    Directory of Open Access Journals (Sweden)

    Koosha Khorramian

    Full Text Available According to recent researches, angle shear connectors are appropriate to transfer longitudinal shear forces across the steel-concrete interface. Angle steel profile has been used in different positions as L-shaped or C-shaped shear connectors. The application of angle shear connectors in tilted positions is of interest in this study. This study investigates the behaviour of tilted-shaped angle shear connectors under monotonic loading using experimental push out tests. Eight push-out specimens are tested to investigate the effects of different angle parameters on the ultimate load capacity of connectors. Two different tilted angles of 112.5 and 135 degrees between the angle leg and steel beam are considered. In addition, angle sizes and lengths are varied. Two different failure modes were observed consisting of concrete crushing-splitting and connector fracture. By increasing the size of connector, the maximum load increased for most cases. In general, the 135 degrees tilted angle shear connectors have a higher strength and stiffness than the 112.5 degrees type.

  14. The qualitative criterion of transient angle stability

    DEFF Research Database (Denmark)

    Lyu, R.; Xue, Y.; Xue, F.;

    2015-01-01

    In almost all the literatures, the qualitative assessment of transient angle stability extracts the angle information of generators based on the swing curve. As the angle (or angle difference) of concern and the threshold value rely strongly on the engineering experience, the validity and robust of...... these criterions are weak. Based on the stability mechanism from the extended equal area criterion (EEAC) theory and combining with abundant simulations of real system, this paper analyzes the criterions in most literatures and finds that the results could be too conservative or too optimistic. It is...

  15. Progress in small angle neutron scattering activities in Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Abdul Aziz Bin Mohamed; Azali Bin Muhamad; Shukri Bin Mohd [Malaysian Institute for Nuclear Technology Research (MINT), Bangi, Kajang (Malaysia)

    1999-10-01

    The current status of SANS (Small Angle Neutron Scattering facility) activities in Malaysia has been presented. Many works need to be done for system improvement before the system can be confidently used as one of effective quality control tools in materials production and engineering sectors. (author)

  16. Improved multistep method for wide-angle beam propagation

    OpenAIRE

    Yamauchi, Junji; Shibayama, Jun; Sekiguchi, Minoru; Nakano, Hisamatsu

    1996-01-01

    To improve a wide-angle beam propagation method using a finite-difference technique, the generalized Douglas scheme for variable coefficients is applied to a multistep method. A truncation error of O(Δx)4 is achieved in the transverse direction. The effectiveness of the present method is demonstrated in the analysis of a tilted step-index slab waveguide.

  17. An Analysis of the Morris Loe Angle Trisection Approximation.

    Science.gov (United States)

    Aslan, Farhad,; And Others

    1992-01-01

    Presents the Morris Loe Angle Trisection Approximation Method to introduce students to areas of mathematics where approximations are used when exact answers are difficult or impossible to obtain. Examines the accuracy of the method using the laws of sines and cosines and a BASIC computer program that is provided. (MDH)

  18. Evolution in opening angle combining DGLAP and BFKL logarithms

    OpenAIRE

    de Oliveira, E. G.; Martin, A. D.(Institute for Particle Physics Phenomenology, University of Durham, DH1 3LE, Durham, UK); Ryskin, M. G.

    2014-01-01

    We present an evolution equation which simultaneously sums the leading BFKL and DGLAP logarithms for the integrated gluon distribution in terms of a single variable, namely the emission angle of the gluon. This form of evolution is appropriate for Monte Carlo simulations of events of high energy pp (and p\\bar{p}) interactions, particularly where small x events are sampled.

  19. Evolution in opening angle combining DGLAP and BFKL logarithms

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, E.G. de [Universidade Federal de Santa Catarina, Departamento de Fisica, CFM, C.P. 476, Florianopolis, SC (Brazil); Martin, A.D. [University of Durham, Institute for Particle Physics Phenomenology, Durham (United Kingdom); Ryskin, M.G. [University of Durham, Institute for Particle Physics Phenomenology, Durham (United Kingdom); Petersburg Nuclear Physics Institute, NRC Kurchatov Institute, St. Petersburg (Russian Federation)

    2014-10-15

    We present an evolution equation which simultaneously sums the leading BFKL and DGLAP logarithms for the integrated gluon distribution in terms of a single variable, namely the emission angle of the gluon. This form of evolution is appropriate for Monte Carlo simulations of events of high energy pp (and p anti p) interactions, particularly where small x events are sampled. (orig.)

  20. Deformation effects in the heavy ion quarter-point angle

    International Nuclear Information System (INIS)

    The effects of static and dynamic deformation on the heavy-ion elastic scattering quarter-point angle are discussed and analyzed in the sudden approximation. Simple expressions are derived within the Fresnel model and applications to several heavy-ion systems are presented. (Author)

  1. Measuring the Stop Mixing Angle at the LHC

    CERN Document Server

    Rolbiecki, Krzysztof; Moortgat-Pick, Gudrid

    2009-01-01

    We present a method to determine the stop mixing angle and its CP-violating phase at the LHC. As an observable we use ratios of branching ratios for different decay modes of the light stop ~t_1 to charginos and neutralinos. These observables can have a very strong dependence on the parameters of the stop sector. We discuss in detail the origin of these effects. Using various combinations of the ratios of branching ratios we show that, depending on the scenario, one can achieve accuracies in the range of a few percent for determining the light stop mass, the mixing angle and the CP phase.

  2. Extra-Axial Medulloblastoma in the Cerebellar Hemisphere

    OpenAIRE

    Chung, Eui Jin; Jeun, Sin Soo

    2014-01-01

    Extra-axial medulloblastoma is a rare phenomenon. We report a case in a 5-year-old boy who presented with nausea, vomiting, and gait disturbance. He was treated with total removal of the tumor. This is the first case of an extra-axially located medulloblastoma occurring in the cerebellar hemisphere posteriolateral to the cerebellopontine angle in Korea. Although the extra-axial occurrence of medulloblastoma is rare, it should be considered in the differential diagnosis of extra-axial lesions ...

  3. Trigeminocardiac Reflex during Maxillary Reconstruction Surgery: A Case Report

    OpenAIRE

    Mayank Kulshrestha; Sahil Kapur; Col. M Kapadia

    2014-01-01

    Systemic hypotension, cardiac dysrhythmia especially bradycardia, apnoea, and gastric hypermotility occurring presumably after stimulation of any of the sensory branches of trigeminal nerve is coined as trigeminocardiac reflex (TCR). It has been described to occur in various surgeries like cerebello-pontine angle and pituitary fossa surgeries. Such bradycardic reflex responses have also been observed during maxillofacial surgeries. The TCR presents as a challenge to both the Anaesthesiologis...

  4. Estimation of crank angle for cycling with a powered prosthesis.

    Science.gov (United States)

    Lawson, B E; Shultz, A; Ledoux, E; Goldfarb, M

    2014-01-01

    In order for a prosthesis to restore power generation during cycling, it must supply torque in a manner that is coordinated with the motion of the bicycle crank. This paper outlines an algorithm for the real time estimation of the angular position of a bicycle crankshaft using only measurements internal to an intelligent knee and ankle prosthesis. The algorithm assumes that the rider/prosthesis/bicycle system can be modeled as a four-bar mechanism. Assuming that a prosthesis can generate two independent angular measurements of the mechanism (in this case the knee angle and the absolute orientation of the shank), Freudenstein's equation can be used to synthesize the mechanism continuously. A recursive least-squares algorithm is implemented to estimate the Freudenstein coefficients, and the resulting link lengths are used to reformulate the equation in terms of input-output relationships mapping both measured angles to the crank angle. Using two independent measurements allows the algorithm to uniquely determine the crank angle from multi-valued functions. In order to validate the algorithm, a bicycle was mounted on a trainer and configured with the prosthesis using an artificial hip joint attached to the seat post. Motion capture was used to monitor the mechanism for forward and backward pedaling and the results are compared to the output of the presented algorithm. Once the parameters have converged, the algorithm is shown to predict the crank angle within 15° of the externally measured value throughout the entire crank cycle during forward rotation.

  5. Controlling Compressor Vane Flow Vectoring Angles at Transonic Speeds

    Science.gov (United States)

    Munson, Matthew; Rempfer, Dietmar; Williams, David; Acharya, Mukund

    2003-11-01

    The ability to control flow separation angles from compressor inlet guide vanes with a Coanda-type actuator is demonstrated using both wind tunnel experiments and finite element simulations. Vectoring angles up to 40 degrees from the uncontrolled baseline state were measured with helium schlieren visualization at transonic Mach numbers ranging from 0.1 to 0.6, and with airfoil chord Reynolds numbers ranging from 89,000 to 710,000. The magnitude of the vectoring angle is shown to depend upon the geometry of the trailing edge, and actuator slot size, and the momentum flux coefficient. Under certain conditions the blowing has no effect on the vectoring angle indicating that the Coanda effect is not present. DNS simulations with the finite element method investigated the effects of geometry changes and external flow. Continuous control of the vectoring angle is demonstrated, which has important implications for application to rotating machinery. The technique is shown to reduce the stall flow coefficient by 15 percent in an axial flow compressor.

  6. Numerical study of hub taper angle on podded propeller performance

    International Nuclear Information System (INIS)

    Presently, the majority of podded propulsion systems are of the pulling type, because this type provides better hydrodynamic efficiency than the pushing type. There are several possible explanations for the better overall performance of a puller type podded propulsor. One is related to the difference in hub shape. Puller and pusher propellers have opposite hub taper angles, hence different hub and blade root shape. These differences cause changes in the flow condition and possibly influence the overall performance. The current study focuses on the variation in performance of pusher and puller propellers with the same blade sections, but different hub taper angles. A hyperboloidal low order source doublet steady/unsteady time domain panel method code was modified and used to evaluate effects of hub taper angle on the open water propulsive performance of some fixed pitch screw propellers used in podded propulsion systems. The modified code was first validated against measurements of two model propellers in terms of average propulsive performance and good agreement was found. Major findings include significant effects of hub taper angle on propulsive performance of tapered hub propellers and noticeable effects of hub taper angle on sectional pressure distributions of tapered hub propeller blades. (author)

  7. Citalopram associated with acute angle-closure glaucoma: case report

    Directory of Open Access Journals (Sweden)

    Hassan Sabit

    2005-10-01

    Full Text Available Abstract Background Acute angle-closure glaucoma is a rare complication in patients receiving anti-depressant treatment. In the following case, we report the development of acute angle closure glaucoma in a patient who overdosed on Citalopram, an antidepressant, and discuss the possible etiological mechanisms for the condition. Case presentation We report a 54 year old, Caucasian lady, with depression and alcohol dependence syndrome, who developed acute angle-closure glaucoma after an overdose of Citalopram, along with alcohol. She was treated with medications and had bilateral Yag laser iridotomies to correct the glaucoma and has made complete recovery. In this case, the underlying cause for glaucoma appears to be related to the ingestion of Citalopram. Conclusion The patho-physiological basis for acute angle closure glaucoma in relation to antidepressant medications remains unclear. The authors suggest Citalopram may have a direct action on the Iris or Ciliary body muscle through serotonergic or anti-cholinergic mechanisms or both. This case highlights the importance of the awareness of the underlying risks, which may predispose an individual to develop acute angle-closure glaucoma, and reminds the clinicians the significance of history taking and examination of the eye before and after starting anti-depressants. This area needs to be further researched.

  8. Multi angle view of lung using optical coherence tomography (OCT)

    Science.gov (United States)

    Golabchi, Ali; DiMarzio, Charles A.; Gouldstone, Andrew

    2012-03-01

    Lung imaging, visualization and measurement of alveolar volume has great importance in determining lung health. However, the heterogeneity of lung tissue complicates this task. In this paper multi angle Optical Coherence Tomography (OCT) is used to overcome this problem. One of the limitations of utilizing OCT in lung is the speckle noise and artifacts that originate from the refraction at the tissue-air interface inside the lung. Multi angle view of lung using OCT is incoherent summation of multiple angle-diverse images. Utilizing image registration of multi angle OCT scans of the lung helps reduce the speckle noise and refraction artifacts. This technique helps extract more information from the images which improves visualization and the ability to measure the geometry of alveoli. The other diculty of utilizing OCT is interpreting the images due to the low numerical aperture (NA) on the OCT. The multi angle view of the lung increases NA, which increase the imaging resolution through synthetic aperture imaging. In this paper in ated excised lung tissue and lung phantom are presented.

  9. Numerical study of hub taper angle on podded propeller performance

    Energy Technology Data Exchange (ETDEWEB)

    Islam, M.F.; Veitch, B.; Bose, N. [Memorial Univ. of Newfoundland, Faculty of Engineering and Applied Science, St. John' s, Newfoundland (Canada)]. E-mail: Mohammed.Islam@nrc-cnrc.gc.ca; Liu, P. [National Research Council of Canada, Inst. for Ocean Technology (IOT), St. John' s, Newfoundland (Canada)

    2005-07-01

    Presently, the majority of podded propulsion systems are of the pulling type, because this type provides better hydrodynamic efficiency than the pushing type. There are several possible explanations for the better overall performance of a puller type podded propulsor. One is related to the difference in hub shape. Puller and pusher propellers have opposite hub taper angles, hence different hub and blade root shape. These differences cause changes in the flow condition and possibly influence the overall performance. The current study focuses on the variation in performance of pusher and puller propellers with the same blade sections, but different hub taper angles. A hyperboloidal low order source doublet steady/unsteady time domain panel method code was modified and used to evaluate effects of hub taper angle on the open water propulsive performance of some fixed pitch screw propellers used in podded propulsion systems. The modified code was first validated against measurements of two model propellers in terms of average propulsive performance and good agreement was found. Major findings include significant effects of hub taper angle on propulsive performance of tapered hub propellers and noticeable effects of hub taper angle on sectional pressure distributions of tapered hub propeller blades. (author)

  10. Star tracker axis-to-sunlit earth horizon angle constraint evaluations for rendezvous operations

    Science.gov (United States)

    Hutchison, W. L.

    1975-01-01

    The results are presented of a study initiated to evaluate the star tracker axis-to-sunlit earth horizon angle constraint with respect to limitations imposed on the passive target rendezvous capability. The data presented include considerations for dispersions and sensor pointing capabilities and generalizations with respect to the uncertainties associated with the angle constraint available in practice.

  11. Interdisciplinary Mathematics-Physics Approaches to Teaching the Concept of Angle in Elementary School

    Science.gov (United States)

    Munier, Valerie; Merle, Helene

    2009-01-01

    The present study takes an interdisciplinary mathematics-physics approach to the acquisition of the concept of angle by children in Grades 3-5. This paper first presents the theoretical framework we developed, then we analyse the concept of angle and the difficulties pupils have with it. Finally, we report three experimental physics-based teaching…

  12. Corner detection using arc length-based angle estimator

    Science.gov (United States)

    Zhang, Shizheng; Yang, Dan; Huang, Sheng; Zhang, Xiaohong; Qu, Ying; Tu, Liyun; Ren, Zemin

    2015-11-01

    We present a corner-detection method named arc length-based angle estimator (AAE). Different from most of the existing approaches, AAE focuses on employing angle detection for finding corners, because angle is an important measure for discrete curvature. AAE provides a new robust solution to the estimation of the K-cosine. In AAE, the K-cosine estimation issue in the x, y space is considered as the problem of the slope estimations in the s, x and s, y spaces, where s is the arc length. Then, weighted least square fitting is employed to address such a slope estimation issue. Experimental results demonstrate that AAE can achieve promising performance in comparison with some recent state-of-the-art approaches under two commonly used evaluation metrics, namely average repeatability and localization error criteria.

  13. Determining pitch-angle diffusion coefficients from test particle simulations

    CERN Document Server

    Ivascenko, A; Spanier, F; Vainio, R

    2016-01-01

    Transport and acceleration of charged particles in turbulent media is a topic of great interest in space physics and interstellar astrophysics. These processes are dominated by the scattering of particles off magnetic irregularities. The scattering process itself is usually described by small-angle scattering with the pitch-angle coefficient $D_{\\mu\\mu}$ playing a major role. Since the diffusion coefficient $D_{\\mu\\mu}$ can be determined analytically only for the approximation of quasi-linear theory, the determination of this coefficient from numerical simulations has, therefore, become more important. So far these simulations yield particle tracks for small-scale scattering, which can then be interpreted using the running diffusion coefficients. This method has a limited range of validity. This paper presents two new methods that allow for the calculation of the pitch-angle diffusion coefficient from numerical simulations. These methods no longer analyse particle trajectories, but the change of particle dist...

  14. Experimental investigation of synthetic aperture flow angle estimation

    DEFF Research Database (Denmark)

    Oddershede, Niels; Jensen, Jørgen Arendt

    2005-01-01

    Currently synthetic aperture flow methods can find the correct velocity magnitude, when the flow direction is known. To make a fully automatic system, the direction should also be estimated. Such an approach has been suggested by Jensen (2004) based on a search of the highest cross-correlation as......Currently synthetic aperture flow methods can find the correct velocity magnitude, when the flow direction is known. To make a fully automatic system, the direction should also be estimated. Such an approach has been suggested by Jensen (2004) based on a search of the highest cross......-correlation as a function of velocity and angle. This paper presents an experimental investigation of this velocity angle estimation method based on a set of synthetic aperture flow data measured using our RASMUS experimental ultrasound system. The measurements are performed for flow angles of 60, 75, and 90 deg...

  15. Generalised action-angle coordinates defined on island chains

    CERN Document Server

    Dewar, Robert L; Gibson, Ashley M

    2012-01-01

    Straight-field-line coordinates are very useful for representing magnetic fields in toroidally confined plasmas, but fundamental problems arise regarding their definition in 3-D geometries because of the formation of islands and chaotic field regions, ie non-integrability. In Hamiltonian dynamical systems terms these coordinates are a form of action-angle variables, which are normally defined only for integrable systems. In order to describe 3-D magnetic field systems, a generalisation of this concept was proposed recently by the present authors that unified the concepts of ghost surfaces and quadratic-flux-minimising (QFMin) surfaces. This was based on a simple canonical transformation generated by a change of variable $\\theta = \\theta(\\Theta,\\zeta)$, where $\\theta$ and $\\zeta$ are poloidal and toroidal angles, respectively, with $\\Theta$ a new poloidal angle chosen to give pseudo-orbits that are a) straight when plotted in the $\\zeta,\\Theta$ plane and b) QFMin pseudo-orbits in the transformed coordinate. Th...

  16. Automated measurement of diagnostic angles for hip dysplasia

    DEFF Research Database (Denmark)

    de Raedt, Sepp; Mechlenburg, Inger Buur; Stilling, Maiken;

    2013-01-01

    A fully automatic method for measuring diagnostic angles of hip dysplasia is presented. The method consists of the automatic segmentation of CT images and detection of anatomical landmarks on the femur and acetabulum. The standard angles used in the diagnosis of hip dysplasia are subsequently....... These values correspond to values found in evaluating interobserver and intraobserver variation for manual measurements. The method can be used in clinical practice to replace the current manual measurements performed by radiologists. In the future, the method will be integrated into an intraoperative surgical...... automatically calculated. Previous work in automating the measuring of angles required the manual segmentation or delineation of the articular joint surface. In the current work automatic segmentation is established using graph-cuts with a cost function based on a sheetness score to detect the sheet...

  17. Analysis of a Low-Angle Annular Expander Nozzle

    Directory of Open Access Journals (Sweden)

    Kyll Schomberg

    2015-01-01

    Full Text Available An experimental and numerical analysis of a low-angle annular expander nozzle is presented to observe the variance in shock structure within the flow field. A RANS-based axisymmetric numerical model was used to evaluate flow characteristics and the model validated using experimental pressure readings and schlieren images. Results were compared with an equivalent converging-diverging nozzle to determine the capability of the wake region in varying the effective area of a low-angle design. Comparison of schlieren images confirmed that shock closure occurred in the expander nozzle, prohibiting the wake region from affecting the area ratio. The findings show that a low angle of deflection is inherently unable to influence the effective area of an annular supersonic nozzle design.

  18. Flow tilt angles near forest edges - Part 2: Lidar anemometry

    DEFF Research Database (Denmark)

    Dellwik, Ebba; Mann, Jakob; Bingöl, Ferhat

    2010-01-01

    from a conically scanning lidar. In this mode of measurement, the lidar beam is rotated in a circle by a prism with a fixed angle to the vertical at varying focus distances. By fitting a trigonometric function to the scans, the mean vertical velocity can be estimated. Lidar measurements from (1......) a fetch-limited beech forest site taken at 48–175 m a.g.l. (above ground level), (2) a reference site in flat agricultural terrain and (3) a second reference site in complex terrain are presented. The method to derive flow tilt angles and mean vertical velocities from lidar has several advantages compared....... The estimated mean vertical velocity is biased if the flow over the scanned circle is not homogeneous. It is demonstrated that the error on the mean vertical velocity due to flow inhomogeneity can be approximated by a function of the angle of the lidar beam to the vertical and the vertical gradient of the mean...

  19. Malignant Transformation Six Months after Removal of Intracranial Epidermoid Cyst: A Case Report

    Directory of Open Access Journals (Sweden)

    Fayçal Lakhdar

    2011-01-01

    Full Text Available Intracranial epidermoid cysts are uncommon benign tumors of developmental origin; malignant transformation of benign epidermoid cysts is rare, and their prognosis remains poor. We report a case of squamous cell carcinoma arising in the cerebellopontine angle. A 52-year-old man presented with left facial paralysis and cerebellar ataxia. He had undergone total removal of a benign epidermoid cyst six months previously. Postoperative magnetic resonance imaging of the brain revealed a heterogeneous and cystic lesion in the left cerebellopontine angle with hydrocephalus. The cyst wall was enhanced by gadolinium. He underwent ventricle-peritoneal shunt and removal again; the histopathological examination revealed a squamous cell carcinoma possibly arising from an underlying epidermoid cyst. This entity is being reported for its rarity. The presence of contrast enhancement at the site of an epidermoid cyst combined with an acute, progressive neurological deficit should alert the neurosurgeon to the possibility of a malignant transformation.

  20. Distribution of angles in hyperbolic lattices

    DEFF Research Database (Denmark)

    Risager, Morten Skarsholm; Truelsen, Jimi Lee

    2010-01-01

    We prove an effective equidistribution result about angles in a hyperbolic lattice. We use this to generalize a result from the study by Boca.......We prove an effective equidistribution result about angles in a hyperbolic lattice. We use this to generalize a result from the study by Boca....

  1. Distribution of Angles in Hyperbolic Lattices

    DEFF Research Database (Denmark)

    S. Risager, Morten; L. Truelsen, Jimi

    2008-01-01

    We prove an effective equidistribution result about angles in a hyperbolic lattice. We use this to generalize a result due to F. P. Boca.......We prove an effective equidistribution result about angles in a hyperbolic lattice. We use this to generalize a result due to F. P. Boca....

  2. Acute angle closure glaucoma following ileostomy surgery

    Directory of Open Access Journals (Sweden)

    Mariana Meirelles Lopes

    2015-02-01

    Full Text Available Angle-closure glaucoma can be induced by drugs that may cause pupillary dilatation. We report a case of a patient that developed bilateral angle closure glaucoma after an ileostomy surgery because of systemic atropine injection. This case report highlights the importance of a fast ophthalmologic evaluation in diseases with ocular involvement in order to make accurate diagnoses and appropriate treatments.

  3. CKM angle $\\gamma$ from LHCb

    CERN Multimedia

    Smith, Jackson

    2015-01-01

    Results of the latest $\\gamma$ combination from LHCb are presented, along with the six LHCb measurements used as inputs. In addition, the anticipated precision attainable for measuring $\\gamma$ after the LHCb Upgrade is outlined

  4. Very large solid angle spectrometers

    International Nuclear Information System (INIS)

    The basic conditions of coincidence experiments are discussed and some of the properties of specific detectors covering up to 90% of 4π steradian and presenting a very large momentum bite are shown. It will appear that such detectors, compared to classical iron dipole spectrometers, present larger acceptances, but a smaller resolving power and a rather low background rejection. The choice of which of these two solutions is to be used depends on the conditions of the specific experiments

  5. Flat strips. A case presentation.

    Directory of Open Access Journals (Sweden)

    Margarita Espinosa Jiménez

    2003-07-01

    Full Text Available This research paper presents a case of a 12 year old . Give with Angle´s Malocclusion class II, division I, with a 10 mms protuberance and an overpass of complete crown to whom a functional device with plane trail was applied . At 8 months follow up molar relation class I , a 4 mms protuberance and an overpass of the third part of the crown is observed. These results have been assessed as a satisfactory evolution of the patient.

  6. Sunspot Tilt Angles Measured with MDI/SOHO and HMI/SDO

    Science.gov (United States)

    Li, J.; Ulrich, R. K.

    2015-12-01

    We present sunspot magnetic tilt angles measured from 1996 to the present time, spanning almost two solar cycles. Full disk magnetograms from MDI/SoHO and HMI/SDO are used in our study. The data cadence in our analyses is 96 minutes per day giving about 90 measurements of the tilt angles for each sunspot during the disk passage between -40 to +40 longitudinal degree. In addition to an automated computation, we use a scheme to visually examine each sunspot efficiently to check the tilt angle determinations. Such measurements not only confirm Joy's and Hale's laws, but also reveal the tilt angle variations during the sunspot lifetime, the effect of Coriolis force on the magnetic flux tubes, and the tilt angle dependence of the cycle progress. The measurements also provide uncertainties on the tilt angle measurements.

  7. Nonadiabatic Hannay's Angle of Spin One Half in Grassmannian Version and Invariant Angle Coherent States

    OpenAIRE

    Cherbal, Omar; Maamache, Mustapha; Drir, Mahrez

    2003-01-01

    We propose to determinate the nonadiabatic Hannay’s angle of spin one half in a varying external magnetic field, by using an averaged version of the variational principal. We also show how the evolution and this nonadiabatic Hannay’s angle is associated with the evolution of Grassmannian invariant-angle coherent states.

  8. Magic Angle Spinning NMR Metabolomics

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jian Z.

    2016-05-31

    Nuclear Magnetic Resonance (NMR) spectroscopy is a non-destructive, quantitative, reproducible, untargeted and unbiased method that requires no or minimal sample preparation, and is one of the leading analytical tools for metabonomics research [1-3]. The easy quantification and the no need of prior knowledge about compounds present in a sample associated with NMR are advantageous over other techniques [1,4]. 1H NMR is especially attractive because protons are present in virtually all metabolites and its NMR sensitivity is high, enabling the simultaneous identification and monitoring of a wide range of low molecular weight metabolites.

  9. Analysis of factors affecting angle ANB.

    Science.gov (United States)

    Hussels, W; Nanda, R S

    1984-05-01

    Cephalometric analyses based on angular and linear measurements have obvious fallacies, which have been discussed in detail by Moyers and Bookstein. However, the clinical application of such an analysis by the orthodontic profession in treatment planning is widely accepted. Variations of angle ANB are commonly used to determine relative jaw relationships in most of the cephalometric evaluations. Several authors, including points A and B influences angle ANB, as does rotational growth of the upper and lower jaws. In addition, the authors point out that growth in a vertical direction (distance N to B) and an increase of the dental height (distance A to B) may contribute to changes in angle ANB. For a Class I relation (Wits = 0 mm), a mathematical formula has been developed which enables the authors to study the geometric influence of angle ANB caused by the following four effects: (1) rotation of the jaws and/or occlusal plane relative to the anterior cranial base; (2) anteroposterior position of N relative to point B, (3) vertical growth (distance N to B); (4) increase in dental height (distance A to B). It was observed that, contrary to the common belief that an ANB angle of 2 +/- 3.0 degrees is considered normal for a skeletal Class I relation, the calculated values of angle ANB will vary widely with changes in these four controlling factors under the same skeletal Class I conditions (Wits = 0 mm). Therefore, in a case under consideration, angle ANB must be corrected for these geometric effects in order to get a proper perspective of the skeletal discrepancy. This is facilitated by comparing the measured ANB angle with the corresponding ANB angle calculated by a formula for a Class I relationship. The corresponding calculated angle ANB can be taken from the tables which are based upon the formula using the same values for SNB, omega (angle between occlusal plane and anterior cranial base), b (which is distance N to B) and a (dental height measured as perpendicular

  10. The range of options for handling plane angle and solid angle within a system of units

    Science.gov (United States)

    Quincey, Paul

    2016-04-01

    The radian and steradian are unusual units within the SI, originally belonging to their own category of ‘supplementary units’, with this status being changed to dimensionless ‘derived units’ in 1995. Recent papers have suggested that angles could be handled in two different ways within the SI, both differing from the present system. The purpose of this paper is to provide a framework for putting such suggestions into context, outlining the range of options that is available, together with the advantages and disadvantages of these options. Although less rigorously logical than some alternatives, the present SI approach is generally supported, but with some changes to the SI brochure to make the position clearer, in particular with regard to the designation of the radian and steradian as derived units.

  11. A coupled elastoplastic-damage constitutive model with Lode angle dependent failure criterion

    OpenAIRE

    Erice Echávarri, Borja; Galvez Diaz-Rubio, Francisco

    2014-01-01

    A coupled elastoplastic-damage constitutive model with Lode angle dependent failure criterion for high strain and ballistic applications is presented. A Lode angle dependent function is added to the equivalent plastic strain to failure definition of the Johnson–Cook failure criterion. The weakening in the elastic law and in the Johnson–Cook-like constitutive relation implicitly introduces the Lode angle dependency in the elastoplastic behaviour. The material model is calibrated for precipitat...

  12. Effect of leaning angle of gecko-inspired slanted polymer nanohairs on dry adhesion

    Science.gov (United States)

    Jeong, Hoon Eui; Lee, Jin-Kwan; Kwak, Moon Kyu; Moon, Sang Heup; Suh, Kahp Yang

    2010-01-01

    We present analysis of adhesion properties of angled polymer nanohairs with a wide range of leaning angles from 0° to 45° and ultraviolet (UV)-curable polyurethane acrylate (PUA) materials of two different elastic moduli (19.8 and 320 MPa). It is demonstrated that shear adhesion and adhesion hysteresis can be greatly enhanced by increasing the leaning angle of nanohairs both for soft and hard materials due to increased contact area and reduced structural stiffness.

  13. The small angle neutron spectrometer at the HANARO reactor, Korea

    Science.gov (United States)

    Seong, B.-S.; Han, Y.-S.; Lee, C.-H.; Lee, J.-S.; Hong, K.-P.; Park, K.-N.; Kim, H.-J.

    A new small angle neutron spectrometer (SANS) has been installed on the CN beam tube at the 30 MW HANARO Research Reactor in the Korea Atomic Energy Research Institute (KAERI). The SANS is to be used for the study of microstructural inhomogeneities in materials in the 1 nm to 100 nm size range. In this paper, the design characteristics of the spectrometer are presented in detail, and several SANS results for standard samples are presented which illustrate its performance.

  14. Analysis and design of wide-angle foveated optical systems

    Science.gov (United States)

    Curatu, George

    2009-12-01

    The development of compact imaging systems capable of transmitting high-resolution images in real-time while covering a wide field-of-view (FOV) is critical in a variety of military and civilian applications: surveillance, threat detection, target acquisition, tracking, remote operation of unmanned vehicles, etc. Recently, optical foveated imaging using liquid crystal (LC) spatial light modulators (SLM) has received considerable attention as a potential approach to reducing size and complexity in fast wide-angle lenses. The fundamental concept behind optical foveated imaging is reducing the number of elements in a fast wide-angle lens by placing a phase SLM at the pupil stop to dynamically compensate aberrations left uncorrected by the optical design. In the recent years, considerable research and development has been conducted in the field of optical foveated imaging based on the LC SLM technology, and several foveated optical systems (FOS) prototypes have been built. However, most research has been focused so far on the experimental demonstration of the basic concept using off-the-shelf components, without much concern for the practicality or the optical performance of the systems. Published results quantify only the aberration correction capabilities of the FOS, often claiming diffraction-limited performance at the region of interest (ROI). However, these results have continually overlooked diffraction effects on the zero-order efficiency and the image quality. The research work presented in this dissertation covers the methods and results of a detailed theoretical research study on the diffraction analysis, image quality, design, and optimization of fast wide-angle FOSs based on the current transmissive LC SLM technology. The amplitude and phase diffraction effects caused by the pixelated aperture of the SLM are explained and quantified, revealing fundamental limitations imposed by the current transmissive LC SLM technology. As a part of this study, five

  15. Surface mobility and structural transitions of poly(n-alkyl methacrylates) probed by dynamic contact angle measurements

    NARCIS (Netherlands)

    Damme, van H.S.; Hogt, A.H.; Feijen, J.

    1986-01-01

    Dynamic contact angles and contact-angle hysteresis of a series of poly(n-alkyl methacrylates) (PAMA) were investigated using the Wilhelmy plate technique. The mobility of polymer surface chains, segments, and side groups affected the measured contact angles and their hysteresis. A model is presente

  16. Qualitative criterion for atom sputtering angle distributions

    International Nuclear Information System (INIS)

    A model is introduced to explain the shape of atom polar emission angle distributions for monocomponent targets sputtered by normally incident keV - energy ions. Analytical expressions are obtained from the model which make it possible to identify three known kinds of the angle distributions - subcosinus, isotropic and supracosinus, for given ion energies and target-ion pairs. Furthermore the fourth, hybrid false-isotropic distribution is found, which is superposition of supracosinus and subcosinus distributions. The theoretical predictions of the angle distributions shape agree with the numerical modeling for sputtering of carbon and platinum by 0.1-10 keV Ar+ ions

  17. Phase-angle controller for Stirling engines

    Science.gov (United States)

    Mcdougal, A. R. (Inventor)

    1980-01-01

    An actuator includes a restraint link adapted to be connected with a pivotal carrier arm for a force transfer gear interposed between the crankshaft for an expander portion of a Stirling engine and a crankshaft for the displacer portion of the engine. The restraint link is releasably trapped hydraulic fluid for selectively establishing a phase angle relationship between the crankshaft. A second embodiment incorporates a hydraulic coupler for use in varying the phase angle of gear-coupled crank fpr a Stirling engine whereby phase angle changes are obtainable.

  18. Bite Angle Effects in Hydroformylation Catalysis

    Institute of Scientific and Technical Information of China (English)

    van LEEUWEN

    2001-01-01

    Recent advances in rhodium catalyzed hydroformylation using xanthene-based ligands will be reviewed.The calculated natural bite angles of the ligands discussed are in the range 100-123℃ While the general trend is clear-higher 1:b ratios at wider angles, small changes in the bite angle do not exhibit a regular effect on the selectivity of the reaction.The same is true for the rate of CO dissociation;the larger the rate of the CO dissociation, the larger the rate of hydroformylation, but for small changes the effects do not comply with this rule.

  19. Impact Angle Control of Interplanetary Shock Geoeffectiveness

    CERN Document Server

    Oliveira, D M

    2015-01-01

    We use OpenGGCM global MHD simulations to study the nightside magnetospheric, magnetotail, and ionospheric responses to interplanetary (IP) fa st forward shocks. Three cases are presented in this study: two inclined oblique shocks, here after IOS-1 and IOS-2, where the latter has a Mach number twice stronger than the former. Both shocks have impact angles of 30$^o$ in relation to the Sun-Earth line. Lastly, we choose a frontal perpendicular shock, FPS, whose shock normal is along the Sun-Earth line, with the same Mach number as IOS-1. We find that, in the IOS-1 case, due to the north-south asymmetry, the magnetotail is deflected southward, leading to a mild compression. The geomagnetic activity observed in the nightside ionosphere is then weak. On the other hand, in the head-on case, the FPS compresses the magnetotail from both sides symmetrically. This compression triggers a substorm allowing a larger amount of stored energy in the magnetotail to be released to the nightside ionosphere, resulting in stronger...

  20. The solid angle through the vertical rectangle

    Science.gov (United States)

    Schröer, H.

    We want to determine the solid angle through the vertical rectangle. We use the cosine law for sides and the spherical law of sines. The relation to luminous flux (radiant flux or radiant power) is shown.

  1. The solid angle through the isosceles triangle

    Science.gov (United States)

    Schröer, H.

    We want to determine the solid angle through the isosceles triangle. We use the cosine law for sides and the spherical law of sines. The relation to luminous flux(radiant flux or radiant power) is shown.

  2. The solid angle through the inclined rectangle

    Science.gov (United States)

    Schröer, H.

    We want to determine the solid angle through the inclined rectangle. We use the cosine law for sides and the spherical law of sines. The relation to luminous flux(radiant flux or radiant power) is shown.

  3. Lateral angle and cranial base sexual dimorphism

    DEFF Research Database (Denmark)

    Duquesnel Mana, Mathilde; Adalian, Pascal; Lynnerup, Niels

    2016-01-01

    SUMMARY: Previous studies have yielded very different results in sex estimation based on measurements of the lateral angle (LA) of the temporal bone. The purpose of this study was to, first, investigate if the bad results obtained by the LA method could be due to the methodology and then, second......, to examine sexual dimorphism in the relationship between the lateral angle and cranial base shape. The lateral angle method was tested using a forensic sample of 102 CT scans of the head with known sex. We measured the angle using two methods: measurements directly on the CT slide, the method usually applied......, and by use of a new method, using a "virtual cast". The cranial base was quantified by placing 12 landmarks in the posterior fossa. Procrustes analysis, principal component analysis, discriminant analysis and cross-validation test were performed. The "cast method" was found to be less accurate than...

  4. Angle measurement error and compensation for decentration rotation of circular gratings

    Institute of Scientific and Technical Information of China (English)

    CHEN Xi-jun; WANG Zhen-huan; ZENG Qing-shuang

    2010-01-01

    As the geometric center of circular grating does not coincide with the rotation center,the angle measurement error of circular grating is analyzed.Based on the moire fringe equations in decentration condition,the mathematical model of angle measurement error is derived.It is concluded that the deeentration between the centre of circular grating and the center of revolving shaft leads to the first-harmonic error of angle measurement.The correctness of the result is proved by experimental data.The method of error compensation is presented,and the angle measurement accuracy of the circular grating is effectively improved by the error compensation.

  5. Definition of resulting angle of the deviation after the passage of neutrons through the crystal

    International Nuclear Information System (INIS)

    The present paper is dedicated to the consideration of passage of neutrons in the crystal. The expression for intensity distribution is obtained by the method of the multiple scattering theories. The received results are applied to calculation angle of the deviation of neutrons by nucleus of the crystal. Here is shown that at the large angle of deviation, the intensity of distribution decreases with reduction of angle much more slowly than till Gaussian law. The received expression for the angle of the dviation allows defining of the impulse of the neutron

  6. Finite element analysis of hip resurfacing arthroplasty with different implant angles

    International Nuclear Information System (INIS)

    Objective: To explore the biomechanical influences of femoral prosthesis implantation angle in 3-dimensional finite element (3D FE) models of Hip Resurfacing Arthroplasty (HRSA). Methods: Five different implant angles of HRSA 3D FE models were constructed based on the human anatomical data from multislice spiral CT. The femoral prosthesis implantation angle was 120°, 125°, 130°, 135°, 140°, and 145° respectively. Pressure was added on each model to simulate status in normal walking. The patterns of the stress distribution on each model were analyzed. Results: The stress concentration presented at head-neck junction part of the resurfaced femur. The maximum Von Mises stress value was decreased while increasing the femoral implant angles. However, the change was not obviously when the angle range from 135° to 145°. Conclusion: The optimal angle of femoral prosthesis implantation in HRSA is from 135° to 145°. (authors)

  7. Modification of Slenderness Coefficient of Angle Steels

    Institute of Scientific and Technical Information of China (English)

    刘红燕; 李志业

    2004-01-01

    To provide information for amendment to Technical Specifications for Power Transmission Towers (SDGJ94-90), the critical loads of typical compressed angle steels was calculated. The correlation of buckling loads and slenderness of compressed angle steels was obtained with regression. A new slenderness coefficient equation was proposed based on the result of the correlation. A practical measure to ensure good result in nonlinear solution using Arch-length method is put forward.

  8. Flipped Angles and Phases: A Systematic Study

    OpenAIRE

    Ellis, J.; Lopez, J; Nanopoulos, D.; Olive, K.

    1993-01-01

    We discuss systematically the fermion mass and mixing matrices in a generic \\linebreak field-theoretical flipped $SU(5)$ model, with particular applications to neutrino and baryon number-changing physics. We demonstrate that the different quark flavour branching ratios in proton decay are related to the Cabibbo-Kobayashi-Maskawa angles, whereas the lepton flavour branching ratios are undetermined. The light neutrino mixing angles observable via oscillation effects are related to the heavy con...

  9. Angles between subspaces and their tangents

    OpenAIRE

    Zhu, Peizhen; Knyazev, Andrew V.

    2012-01-01

    Principal angles between subspaces (PABS) (also called canonical angles) serve as a classical tool in mathematics, statistics, and applications, e.g., data mining. Traditionally, PABS are introduced via their cosines. The cosines and sines of PABS are commonly defined using the singular value decomposition. We utilize the same idea for the tangents, i.e., explicitly construct matrices, such that their singular values are equal to the tangents of PABS, using several approaches: orthonormal and...

  10. Empirical angle-dependent Biot and MBA models for acoustic anisotropy in cancellous bone.

    Science.gov (United States)

    Lee, Kang Il; Hughes, E R; Humphrey, V F; Leighton, T G; Choi, Min Joo

    2007-01-01

    The Biot and the modified Biot-Attenborough (MBA) models have been found useful to understand ultrasonic wave propagation in cancellous bone. However, neither of the models, as previously applied to cancellous bone, allows for the angular dependence of acoustic properties with direction. The present study aims to account for the acoustic anisotropy in cancellous bone, by introducing empirical angle-dependent input parameters, as defined for a highly oriented structure, into the Biot and the MBA models. The anisotropy of the angle-dependent Biot model is attributed to the variation in the elastic moduli of the skeletal frame with respect to the trabecular alignment. The angle-dependent MBA model employs a simple empirical way of using the parametric fit for the fast and the slow wave speeds. The angle-dependent models were used to predict both the fast and slow wave velocities as a function of propagation angle with respect to the trabecular alignment of cancellous bone. The predictions were compared with those of the Schoenberg model for anisotropy in cancellous bone and in vitro experimental measurements from the literature. The angle-dependent models successfully predicted the angular dependence of phase velocity of the fast wave with direction. The root-mean-square errors of the measured versus predicted fast wave velocities were 79.2 m s(-1) (angle-dependent Biot model) and 36.1 m s(-1) (angle-dependent MBA model). They also predicted the fact that the slow wave is nearly independent of propagation angle for angles about 50 degrees , but consistently underestimated the slow wave velocity with the root-mean-square errors of 187.2 m s(-1) (angle-dependent Biot model) and 240.8 m s(-1) (angle-dependent MBA model). The study indicates that the angle-dependent models reasonably replicate the acoustic anisotropy in cancellous bone.

  11. A Study of Radiation Incidence Angle in Anteroposterior Cervical Vertebra Examination

    International Nuclear Information System (INIS)

    In anteroposterior projection for cervical vertebra, it is general that the incidence angle of X-ray is 15 degrees to 20 degrees to head in order to prevent overlap of mandible and occipital bone and to observe array of cervical interbody and shapes of joints. However, the angle is appropriate for foreigners that was determined by foreign literature review long ago, and there have been few researches of incidence angle for Koreans' body type. The purpose of in this study are to identify the incidence angle appropriate for Koreans and to present methodology. In order to measure the incidence angle, 1,044 patients who visited S Hospital located in Seosan were selected and measured of average length of cervical vertebra, OID, axis angle, and FID. The incidence angle was calculated from the applied formula by measuring average values per age groups and sex (see Formula 1 and 2). The average length of cervical vertebra was 6cm: the length was increased from teenagers to twenties but was decreased since thirties. The difference between males and females was around 1cm (p<.01). The OID was almost the same regardless of age groups and sex. As for axis angle, the slope was increased in teenagers and twenties, but was decreased since thirties. The difference between males and females was around 2 degrees (p<.01). The FID measurements were almost the same regardless of age groups and sex, and when the incidence angle was measured from these values, the teenagers were 15.9 degrees, the twenties were 16.9 degrees, the thirties were 16.6 degrees, the forties were 16.2 degrees, the fifties were 15.9 degrees, and the sixties were 14.5 degrees, indicating that the angle was increased from teenagers to the twenties but decreased since the thirties. While the angles of males and females were measured to be the same in the teenagers, the angle was different between males and females by 2 degrees. When the incidence angle statistically analyzed with measurement of average length of

  12. A Study of Radiation Incidence Angle in Anteroposterior Cervical Vertebra Examination

    Energy Technology Data Exchange (ETDEWEB)

    Jeung, Seung Woon; Lim, Cheong Hwan; Jung, Hong Ryang; Joo, Yeong Cheol; Park, Mi Ja [Dept. of Radiological Science, Hanseo University, Seosan (Korea, Republic of); Han, Beon Hee [Dept. of Radiological Science, Seonam University, Namwon (Korea, Republic of)

    2012-06-15

    In anteroposterior projection for cervical vertebra, it is general that the incidence angle of X-ray is 15 degrees to 20 degrees to head in order to prevent overlap of mandible and occipital bone and to observe array of cervical interbody and shapes of joints. However, the angle is appropriate for foreigners that was determined by foreign literature review long ago, and there have been few researches of incidence angle for Koreans' body type. The purpose of in this study are to identify the incidence angle appropriate for Koreans and to present methodology. In order to measure the incidence angle, 1,044 patients who visited S Hospital located in Seosan were selected and measured of average length of cervical vertebra, OID, axis angle, and FID. The incidence angle was calculated from the applied formula by measuring average values per age groups and sex (see Formula 1 and 2). The average length of cervical vertebra was 6cm: the length was increased from teenagers to twenties but was decreased since thirties. The difference between males and females was around 1cm (p<.01). The OID was almost the same regardless of age groups and sex. As for axis angle, the slope was increased in teenagers and twenties, but was decreased since thirties. The difference between males and females was around 2 degrees (p<.01). The FID measurements were almost the same regardless of age groups and sex, and when the incidence angle was measured from these values, the teenagers were 15.9 degrees, the twenties were 16.9 degrees, the thirties were 16.6 degrees, the forties were 16.2 degrees, the fifties were 15.9 degrees, and the sixties were 14.5 degrees, indicating that the angle was increased from teenagers to the twenties but decreased since the thirties. While the angles of males and females were measured to be the same in the teenagers, the angle was different between males and females by 2 degrees. When the incidence angle statistically analyzed with measurement of average length

  13. Winding angles of long lattice walks

    Science.gov (United States)

    Hammer, Yosi; Kantor, Yacov

    2016-07-01

    We study the winding angles of random and self-avoiding walks (SAWs) on square and cubic lattices with number of steps N ranging up to 107. We show that the mean square winding angle of random walks converges to the theoretical form when N → ∞. For self-avoiding walks on the square lattice, we show that the ratio /2 converges slowly to the Gaussian value 3. For self-avoiding walks on the cubic lattice, we find that the ratio /2 exhibits non-monotonic dependence on N and reaches a maximum of 3.73(1) for N ≈ 104. We show that to a good approximation, the square winding angle of a self-avoiding walk on the cubic lattice can be obtained from the summation of the square change in the winding angles of lnN independent segments of the walk, where the ith segment contains 2i steps. We find that the square winding angle of the ith segment increases approximately as i0.5, which leads to an increase of the total square winding angle proportional to (lnN)1.5.

  14. Footprint Problem with Angle of Attack Optimization for High Lifting Reentry Vehicle

    Institute of Scientific and Technical Information of China (English)

    LI Huifeng; ZHANG Ran; LI Zhaoying; ZHANG Rui

    2012-01-01

    A formal analysis to footprint problem with effects of angle of attack (AOA) is presented.First a flexible and rapid standardized method for footprint generation is developed.Zero bank angle control strategy and the maximum crossrange method are used to obtain virtual target set; afterward,closed-loop bank angle guidance law is used to find footprint by solving closest approach problem for each element in virtual target set.Then based on quasi-equilibrium glide condition,the typical inequality reentry trajectory constraints are converted to angle of attack lower boundary constraint.Constrained by the lower boundary,an original and practical angle of attack parametric method is proposed.By using parametric angle of attack profile,optimization algorithm for angle of attack is designed and the impact of angle of attack to footprint is discussed.Simulations with different angle of attack profiles are presented to demonstrate the performance of the proposed footprint solution method and validity of optimal algorithm.

  15. Radon - an angle of view

    International Nuclear Information System (INIS)

    Apart from its radiation effects on living organism, radon induces the formation of atmospheric ions which are beneficial to man: some asthmatics can breathe more easily in an environment with elevated ion levels, the blood pH increases, the fraction of albumins is higher while the serotonin level is lower, sedimentation decreases and the leukocyte counts in peripherals diminish. The blood pressure, particularly in people suffering from hypertension, drops appreciably. The production of pituitary hormones as well as the overall sexual activity is stimulated by ions in air. Exposure to negative ions affects circulation through the skin, reduces skin temperature and improves overall resistance of the organism to infection. Negative ions also have a stimulating effect on mental activity and help against insomnia. Sites where radon is present in not too high concentrations are often famous as climatic spas. So, antiradon provisions, if exercised too thoroughly, may have adverse rather than positive consequences. All pros and cons should always be taken into account when deciding on antiradon steps. (P.A.)

  16. Dehn functions and finiteness properties of subgroups of perturbed right-angled Artin groups

    CERN Document Server

    Brady, Noel; Lee, Sang Rae

    2011-01-01

    We introduce the class of perturbed right-angled Artin groups. These are constructed by gluing Bieri double groups into standard right-angled Artin groups. As a first application of this construction we obtain families of CAT(0) groups containing finitely presented subgroups which are not of type $\\mathrm{FP}_3$, and have exponential, or polynomial Dehn functions of prescribed degree.

  17. Effects of Series Elasticity on the Human Knee Extension Torque-Angle Relationship in Vivo

    Science.gov (United States)

    Kubo, Keitaro; Ohgo, Kazuya; Takeishi, Ryuichi; Yoshinaga, Kazunari; Tsunoda, Naoya; Kanehisa, Hiroaki; Fukunaga, Tetsuo

    2006-01-01

    The purpose of this study was to investigate the effects of series elasticity on the torque-angle relationship of the knee extensors in vivo. Forty-two men volunteered to take part in the present study. The participants performed maximal voluntary isometric contractions at eight knee-joint angles (40, 50, 60, 70, 80, 90, 100, 110[degree]). The…

  18. Retrieval of Aerosol Optical Depth over Land using two-angle view Satellite Radiometry during TARFOX

    NARCIS (Netherlands)

    Veefkind, J.P.; Leeuw, G. de; Durkee, P.H.

    1998-01-01

    A new aerosol optical depth retrieval algorithm is presented that uses the two-angle view capability of the Along Track Scanning Radiometer 2 (ATSR-2). By combining the two-angle view and the spectral information this so-called dual view algorithm separates between aerosol and surface contributions

  19. IMU-Based Joint Angle Measurement for Gait Analysis

    Directory of Open Access Journals (Sweden)

    Thomas Seel

    2014-04-01

    Full Text Available This contribution is concerned with joint angle calculation based on inertial measurement data in the context of human motion analysis. Unlike most robotic devices, the human body lacks even surfaces and right angles. Therefore, we focus on methods that avoid assuming certain orientations in which the sensors are mounted with respect to the body segments. After a review of available methods that may cope with this challenge, we present a set of new methods for: (1 joint axis and position identification; and (2 flexion/extension joint angle measurement. In particular, we propose methods that use only gyroscopes and accelerometers and, therefore, do not rely on a homogeneous magnetic field. We provide results from gait trials of a transfemoral amputee in which we compare the inertial measurement unit (IMU-based methods to an optical 3D motion capture system. Unlike most authors, we place the optical markers on anatomical landmarks instead of attaching them to the IMUs. Root mean square errors of the knee flexion/extension angles are found to be less than 1° on the prosthesis and about 3° on the human leg. For the plantar/dorsiflexion of the ankle, both deviations are about 1°.

  20. Reflectivity Model of Low Grazing Angle Radar Sea Clutter

    Institute of Scientific and Technical Information of China (English)

    FENG Sheng; CHEN Jie; CAI Tao; TU Xu-yan

    2005-01-01

    The commonly used reflectivity models of radar sea clutter are summarized. Among these models, the adjusted Barton model and the adjusted Morchin model are compared. From the analysis result, the γ-p reflectivity model is presented for low grazing angle radar sea clutter by the adjustment of the original Barton reflectivity model. The model takes into account radar frequency, grazing angle, sea condition, and polarization property. The influences of these factors on the proposed model are analyzed. The model absorbs the merits from commonly used reflectivity models for sea clutter. It introduces several researchers' opinions, and extends them. And it accounts for the reflectivity at arbitrary radar frequency from VHF to X-band, arbitrary low grazing angle, arbitrary sea condition and different polarization property. One of the main results is the proposed γ-p reflectivity model can reflect the influence of polarization on sea clutter reflectivity to some extent. The proposed γ-p reflectivity model of low-angle radar-sea clutter is validated by comparing the simulated and statistically experimental data.

  1. Optical Enhancement of Exoskeleton-Based Estimation of Glenohumeral Angles.

    Science.gov (United States)

    Cortés, Camilo; Unzueta, Luis; de Los Reyes-Guzmán, Ana; Ruiz, Oscar E; Flórez, Julián

    2016-01-01

    In Robot-Assisted Rehabilitation (RAR) the accurate estimation of the patient limb joint angles is critical for assessing therapy efficacy. In RAR, the use of classic motion capture systems (MOCAPs) (e.g., optical and electromagnetic) to estimate the Glenohumeral (GH) joint angles is hindered by the exoskeleton body, which causes occlusions and magnetic disturbances. Moreover, the exoskeleton posture does not accurately reflect limb posture, as their kinematic models differ. To address the said limitations in posture estimation, we propose installing the cameras of an optical marker-based MOCAP in the rehabilitation exoskeleton. Then, the GH joint angles are estimated by combining the estimated marker poses and exoskeleton Forward Kinematics. Such hybrid system prevents problems related to marker occlusions, reduced camera detection volume, and imprecise joint angle estimation due to the kinematic mismatch of the patient and exoskeleton models. This paper presents the formulation, simulation, and accuracy quantification of the proposed method with simulated human movements. In addition, a sensitivity analysis of the method accuracy to marker position estimation errors, due to system calibration errors and marker drifts, has been carried out. The results show that, even with significant errors in the marker position estimation, method accuracy is adequate for RAR. PMID:27403044

  2. Penetrator strength effect in long-rod critical ricochet angle

    International Nuclear Information System (INIS)

    3D numerical simulations were performed in order to further investigate the role of penetrator strength in the interaction of long-rods and oblique targets. Three distinctive regimes resulting from oblique impact depending on the obliquity, namely simple ricochet, critical ricochet and target perforation, were investigated in detail. Critical ricochet angles were calculated with a full 3D explicit finite element method for various impact velocities and strength of target plates and projectiles. Numerical predictions were compared with existing two-dimensional analytical models and test results. It was predicted that critical ricochet angle increases with decreasing impact velocity and that higher ricochet angles were expected if higher strength target materials are employed. But there are differences between analytical models and 3D numerical simulation results or test results. The causes for these discrepancies are established by numerical simulations which explore the validity of the penetrator strength parameter in the analytical model as a physical entity. As a matter of fact, in this paper we first investigate the role of penetrator dynamic strength using two-dimensional simulation which resulted in different penetrator strengths out of different impact velocities. Next, by applying these amounts for penetrator strength in Rosenberg analytical model the critical ricochet angle is calculated. Finally, a comparison between the present analytical method with the 3D simulation and test results shows that the new analytical approach leads to modified results with respect to Rosenberg ones

  3. Longitudinal Changes of Angle Configuration in Primary Angle-Closure Suspects

    Science.gov (United States)

    Jiang, Yuzhen; Chang, Dolly S.; Zhu, Haogang; Khawaja, Anthony P.; Aung, Tin; Huang, Shengsong; Chen, Qianyun; Munoz, Beatriz; Grossi, Carlota M.

    2015-01-01

    Objective To determine longitudinal changes in angle configuration in the eyes of primary angle-closure suspects (PACS) treated by laser peripheral iridotomy (LPI) and in untreated fellow eyes. Design Longitudinal cohort study. Participants Primary angle-closure suspects aged 50 to 70 years were enrolled in a randomized, controlled clinical trial. Methods Each participant was treated by LPI in 1 randomly selected eye, with the fellow eye serving as a control. Angle width was assessed in a masked fashion using gonioscopy and anterior segment optical coherence tomography (AS-OCT) before and at 2 weeks, 6 months, and 18 months after LPI. Main Outcome Measures Angle width in degrees was calculated from Shaffer grades assessed under static gonioscopy. Angle configuration was also evaluated using angle opening distance (AOD250, AOD500, AOD750), trabecular-iris space area (TISA500, TISA750), and angle recess area (ARA) measured in AS-OCT images. Results No significant difference was found in baseline measures of angle configuration between treated and untreated eyes. At 2 weeks after LPI, the drainage angle on gonioscopy widened from a mean of 13.5° at baseline to a mean of 25.7° in treated eyes, which was also confirmed by significant increases in all AS-OCT angle width measures (P<0.001 for all variables). Between 2 weeks and 18 months after LPI, a significant decrease in angle width was observed over time in treated eyes (P<0.001 for all variables), although the change over the first 5.5 months was not statistically significant for angle width measured under gonioscopy (P = 0.18), AOD250 (P = 0.167) and ARA (P = 0.83). In untreated eyes, angle width consistently decreased across all follow-up visits after LPI, with a more rapid longitudinal decrease compared with treated eyes (P values for all variables ≤0.003). The annual rate of change in angle width was equivalent to 1.2°/year (95% confidence interval [CI], 0.8–1.6) in treated eyes and 1.6°/year (95% CI, 1

  4. Trajectory reshaping based guidance with impact time and angle constraints

    Directory of Open Access Journals (Sweden)

    Zhao Yao

    2016-08-01

    Full Text Available This study presents a novel impact time and angle constrained guidance law for homing missiles. The guidance law is first developed with the prior-assumption of a stationary target, which is followed by the practical extension to a maneuvering target scenario. To derive the closed-form guidance law, the trajectory reshaping technique is utilized and it results in defining a specific polynomial function with two unknown coefficients. These coefficients are determined to satisfy the impact time and angle constraints as well as the zero miss distance. Furthermore, the proposed guidance law has three additional guidance gains as design parameters which make it possible to adjust the guided trajectory according to the operational conditions and missile’s capability. Numerical simulations are presented to validate the effectiveness of the proposed guidance law.

  5. Bioelectric impedance phase angle in breast carcinoma

    Directory of Open Access Journals (Sweden)

    Ruchi Tyagi

    2014-01-01

    Full Text Available Context: Worldwide breast cancer is the most frequently diagnosed life threatening cancer and the leading cause of death in women. Bioelectric impedance analysis (BIA affords an emerging opportunity to assess prognosis because of its ability to non invasively assess cell and plasma membrane structure and function by means of phase angle. Aims: To compare the phase angle between patients of breast cancer and their matched control with the help of BIA. Settings and Design: After taking clearance from ethical committee, a total of 34 female cases of histologically proven infiltrating ductal breast carcinoma were included from the surgery IPD, department of surgery. Equal numbers of the matched controls were recruited from the friends and relatives of cases. Materials and Methods: Bio Electrical Impedance Analyzer (BIA BODY STAT QUAD SCAN 4000 was used to measure resistance (R and reactance (Xc by recording a voltage drop in applied current. Phase angle is the ratio of reactance to resistance and is a measure of cell vitality. Statistical analysis used: Unpaired "t" test was applied. Results: In control group, the phase angle showed a mean of 5.479 whereas in test group, it showed a mean value of 4.726. The P value showed a significant difference (P < 0.0001. The smaller the phase angle values were higher was the tumor, nodes, metastases (TNM staging. The phase angles differed significantly from the healthy age matched control values. Conclusions: This study demonstrated that phase angle is a strong predictor of severity of breast cancer and differed significantly between the two groups.

  6. Fractal Approach in Petrology: Combining Ultra-Small Angle (USANA) and Small Angle Neutron Scattering (SANS)

    Energy Technology Data Exchange (ETDEWEB)

    LoCelso, F.; Triolo, F.; Triolo, A.; Lin, J.S.; Lucido, G.; Triolo, R.

    1999-10-14

    Ultra small angle neutron scattering instruments have recently covered the gap between the size resolution available with conventional intermediate angle neutron scattering and small angle neutron scattering instruments on one side and optical microscopy on the other side. Rocks showing fractal behavior in over two decades of momentum transfer and seven orders of magnitude of intensity are examined and fractal parameters are extracted from the combined USANS and SANS curves.

  7. LHCb Measurement of the CKM angle $\\gamma$ at LHCb

    CERN Multimedia

    Ali, S

    2014-01-01

    In this poster we present the latest result by the LHCb collaboration in determining the CKM angle $\\gamma$ ($(67.1 \\pm 12)^{\\circ}$). The result is determined by combining several $B \\to Dh$ analyses. Latest results from the decay time dependent $B_{s} \\to D_{s}K$ analysis is also reported, along with a few other decay channels interesting for determination of $\\gamma$ in the future.

  8. Large-angle Bhabha scattering at LEP 1

    Science.gov (United States)

    Beenakker, Wim; Passarino, Giampiero

    1998-04-01

    A critical assessment is given of the theoretical uncertainty in the predicted cross-sections for large-angle Bhabha scattering at LEP 1, with or without t-channel subtraction. To this end a detailed comparison is presented of the results obtained with the programs ALIBABA and TOPAZ0. Differences in the implementation of the radiative corrections and the effect of missing higher-order terms are critically discussed. © 1998

  9. Large-Angle Bhabha Scattering at LEP 1

    OpenAIRE

    Wim BeenakkerLeiden Univ.; Giampiero Passarino(Dipartimento di Fisica Teorica, Università di Torino, Italy)

    1997-01-01

    A critical assessment is given of the theoretical uncertainty in the predicted cross-sections for large-angle Bhabha scattering at LEP 1, with or without t-channel subtraction. To this end a detailed comparison is presented of the results obtained with the programs ALIBABA and TOPAZ0. Differences in the implementation of the radiative corrections and the effect of missing higher-order terms are critically discussed.

  10. Large-Angle Bhabha Scattering at LEP 1

    CERN Document Server

    Beenakker, W; Beenakker, Wim; Passarino, Giampiero

    1998-01-01

    A critical assessment is given of the theoretical uncertainty in the predicted cross-sections for large-angle Bhabha scattering at LEP 1, with or without t-channel subtraction. To this end a detailed comparison is presented of the results obtained with the programs ALIBABA and TOPAZ0. Differences in the implementation of the radiative corrections and the effect of missing higher-order terms are critically discussed.

  11. Early phacoemulsification in patients with acute primary angle closure

    OpenAIRE

    Moghimi, Sasan; Hashemian, Hesam; Chen, Rebecca; Johari, Mohammadkarim; Mohammadi, Massood; Lin, Shan C.

    2016-01-01

    Purpose To compare long term efficacy of phacoemulsification in the early management of acute primary angle closure (APAC) after aborting an acute attack and performing laser peripheral iridotomy (LPI). Methods In this nonrandomized comparative prospective study, we included 35 subjects presenting with APAC who had responded to medical treatment and LPI with intraocular pressure (IOP) less than 25 mmHg. Twenty patients with visually significant cataract with visual acuity of 21 mmHg with or w...

  12. Small-angle X-ray scattering of solutions

    International Nuclear Information System (INIS)

    The use of synchrotron radiation in small-angle X-ray scattering (SAXS) techniques in biological structural studies is described. The main features of the monochromatic radiation systems and the white radiation systems are considered. The detectors, data acquisition and experimental procedures are briefly described. Experimental results are presented for 1) measurements on dilute solutions and weak scatterers, 2) measurement of conformational transitions, 3) contrast variation experiments, 4) time-resolved measurements and 5) complex contrast variation. (U.K.)

  13. Can pelvis angle be monitored from seat support forces in healthy subjects?

    Science.gov (United States)

    Geffen, Paul van; Veltink, Peter H; Koopman, Bart F J M

    2009-03-01

    Individuals who cannot functionally reposition themselves often need dynamic seating interventions that change body posture from automatic chair adjustments. Pelvis alignment directly affects sitting posture, and systems that adjust and monitor pelvis angle simultaneously might be applicable to control body posture in sitting. The present study explores whether it is feasible to monitor pelvis angle from seat support forces. Pelvis angle estimation was based on equivalent "two-force member" loading for which pelvis orientation equals the orientation of the equivalent contact force. Theoretical evaluation was done to derive important conditions for practical application. An instrumented wheelchair was developed for experimental validation in healthy subjects. Seat support forces were measured, and mechanical analysis was done to derive the equivalent contact force from which we estimated the pelvis angle. Model analysis showed a significant influence of pelvis mass, hip force, and lumbar torque on the relation between the actual pelvis angle and the predicted pelvis angle. Proper force compensation and minimal lumbar torque seemed important for accurate pelvis angle estimations. Experimental evaluation showed no body postures that involved a clear relation between the pelvis angle and the orientation of the equivalent contact force. Findings suggest that pelvis angle could not be estimated in healthy individuals under the described experimental seating conditions. Validation experiments with impaired individuals must be performed under different seating conditions to provide a better understanding whether the principle is of interest for clinical application. PMID:19154073

  14. Collisional quantum interference on rotational energy transfer: physical interpretation of the differential interference angle

    Institute of Scientific and Technical Information of China (English)

    Li Yong-Qing; Li Jian; Ma Feng-Cai

    2006-01-01

    Collisional quantum interference (CQI) on the intramolecular rotational energy transfer is observed in an experiment with a static cell, and the integral interference angles are measured. To obtain more accurate information, an experiment with a molecular beam is carried out, and thereby the relationship between the differential interference angle and the scattering angle is obtained. Based on the first-Born approximation of time-dependent perturbation theory,the theoretical model of CQI is developed in an atom-diatom system in the condition of the molecular beam, with the long-range interaction potential taken into account. The method of measuring correctly the differential interference angle is presented. The tendencies of the differential interference angle changing with the impact parameter and relative velocity are discussed. The theoretical model presented here is important for understanding or performing the experiment in the molecular beam.

  15. Rapid emission angle selection for rotating-shield brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yunlong [Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, Iowa 52242 (United States); Flynn, Ryan T.; Kim, Yusung; Bhatia, Sudershan K.; Sun, Wenqing [Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States); Yang Wenjun [Department of Biomedical Engineering, University of Iowa, 1402 Seamans Center for the Engineering Arts and Sciences, Iowa City, Iowa 52242 (United States); Wu Xiaodong [Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, Iowa 52242 and Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States)

    2013-05-15

    Purpose: The authors present a rapid emission angle selection (REAS) method that enables the efficient selection of the azimuthal shield angle for rotating shield brachytherapy (RSBT). The REAS method produces a Pareto curve from which a potential RSBT user can select a treatment plan that balances the tradeoff between delivery time and tumor dose conformity. Methods: Two cervical cancer patients were considered as test cases for the REAS method. The RSBT source considered was a Xoft Axxent{sup TM} electronic brachytherapy source, partially shielded with 0.5 mm of tungsten, which traveled inside a tandem intrauterine applicator. Three anchor RSBT plans were generated for each case using dose-volume optimization, with azimuthal shield emission angles of 90 Degree-Sign , 180 Degree-Sign , and 270 Degree-Sign . The REAS method converts the anchor plans to treatment plans for all possible emission angles by combining neighboring beamlets to form beamlets for larger emission angles. Treatment plans based on exhaustive dose-volume optimization (ERVO) and exhaustive surface optimization (ERSO) were also generated for both cases. Uniform dwell-time scaling was applied to all plans such that that high-risk clinical target volume D{sub 90} was maximized without violating the D{sub 2cc} tolerances of the rectum, bladder, and sigmoid colon. Results: By choosing three azimuthal emission angles out of 32 potential angles, the REAS method performs about 10 times faster than the ERVO method. By setting D{sub 90} to 85-100 Gy{sub 10}, the delivery times used by REAS generated plans are 21.0% and 19.5% less than exhaustive surface optimized plans used by the two clinical cases. By setting the delivery time budget to 5-25 and 10-30 min/fx, respectively, for two the cases, the D{sub 90} contributions for REAS are improved by 5.8% and 5.1% compared to the ERSO plans. The ranges used in this comparison were selected in order to keep both D{sub 90} and the delivery time within acceptable

  16. Precision measurements of the CKM angle gamma

    CERN Document Server

    CERN. Geneva

    2016-01-01

    The level of CP-violation permitted within the Standard Model cannot account for the matter dominated universe in which we live. Within the Standard Model the CKM matrix, which describes the quark couplings, is expected to be unitary. By making precise measurements of the CKM matrix parameters new physics models can be constrained, or with sufficient precision the effects of physics beyond the standard model might become apparent. The CKM angle gamma is the least well known angle of the unitarity triangle. It is the only angle easily accessible at tree-level, and furthermore has almost no theoretical uncertainties. Therefore it provides an invaluable Standard Model benchmark against which other new physics sensitive tests of the CP-violation can be made. I will discuss recent measurements of gamma using the the Run 1 LHCb dataset, which improve our knowledge of this key parameter.

  17. Notes on large angle crossing graphs

    CERN Document Server

    Dujmovic, Vida; Morin, Pat; Wolle, Thomas

    2009-01-01

    A graph G is an a-angle crossing (aAC) graph if every pair of crossing edges in G intersect at an angle of at least a. The concept of right angle crossing (RAC) graphs (a=Pi/2) was recently introduced by Didimo et. al. It was shown that any RAC graph with n vertices has at most 4n-10 edges and that there are infinitely many values of n for which there exists a RAC graph with n vertices and 4n-10 edges. In this paper, we give upper and lower bounds for the number of edges in aAC graphs for all 0 < a < Pi/2.

  18. High brightness angled cavity quantum cascade lasers

    Energy Technology Data Exchange (ETDEWEB)

    Heydari, D.; Bai, Y.; Bandyopadhyay, N.; Slivken, S.; Razeghi, M., E-mail: razeghi@eecs.northwestern.edu [Center for Quantum Devices, Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, Illinois 60208 (United States)

    2015-03-02

    A quantum cascade laser (QCL) with an output power of 203 W is demonstrated in pulsed mode at 283 K with an angled cavity. The device has a ridge width of 300 μm, a cavity length of 5.8 mm, and a tilt angle of 12°. The back facet is high reflection coated, and the front facet is anti-reflection coated. The emitting wavelength is around 4.8 μm. In distinct contrast to a straight cavity broad area QCL, the lateral far field is single lobed with a divergence angle of only 3°. An ultrahigh brightness value of 156 MW cm{sup −2 }sr{sup −1} is obtained, which marks the brightest QCL to date.

  19. Flocking and invariance of velocity angles.

    Science.gov (United States)

    Liu, Le; Huang, Lihong; Wu, Jianhong

    2016-04-01

    Motsch and Tadmor considered an extended Cucker-Smale model to investigate the flocking behavior of self-organized systems of interacting species. In this extended model, a cone of the vision was introduced so that outside the cone the influence of one agent on the other is lost and hence the corresponding influence function takes the value zero. This creates a problem to apply the Motsch-Tadmor and Cucker-Smale method to prove the flocking property of the system. Here, we examine the variation of the velocity angles between two arbitrary agents, and obtain a monotonicity property for the maximum cone of velocity angles. This monotonicity permits us to utilize existing arguments to show the flocking property of the system under consideration, when the initial velocity angles satisfy some minor technical constraints. PMID:27105986

  20. Ship wakes: Kelvin or Mach angle?

    CERN Document Server

    Rabaud, Marc

    2013-01-01

    From the analysis of a set of airborne images of ship wakes, we show that the wake angles decrease as $U^{-1}$ at large velocities, in a way similar to the Mach cone for supersonic airplanes. This previously unnoticed Mach-like regime is in contradiction with the celebrated Kelvin prediction of a constant angle of $19.47\\degree$ independent of the ship's speed. We propose here a model, confirmed by numerical simulations, in which the finite size of the disturbance explains this transition between the Kelvin and Mach regimes at a Froude number $Fr = U/\\sqrt{gL} \\simeq 0.5$, where $L$ is the hull ship length.

  1. Clinical tibiofemoral angle in south Indian children

    OpenAIRE

    Mathew, S. E.; V. Madhuri

    2013-01-01

    Objectives The development of tibiofemoral angle in children has shown ethnic variations. However this data is unavailable for our population. Methods We measured the tibiofemoral angle (TFA) and intercondylar and intermalleolar distances in 360 children aged between two and 18 years, dividing them into six interrupted age group intervals: two to three years; five to six years; eight to nine years; 11 to 12 years; 14 to 15 years; and 17 to 18 years. Each age group comprised 30 boys and 30 gir...

  2. Ship wakes: Kelvin or Mach angle?

    Science.gov (United States)

    Rabaud, Marc; Moisy, Frédéric

    2013-05-24

    From the analysis of a set of airborne images of ship wakes, we show that the wake angles decrease as U(-1) at large velocities, in a way similar to the Mach cone for supersonic airplanes. This previously unnoticed Mach-like regime is in contradiction with the celebrated Kelvin prediction of a constant angle of 19.47° independent of the ship's speed. We propose here a model, confirmed by numerical simulations, in which the finite size of the disturbance explains this transition between the Kelvin and Mach regimes at a Froude number Fr=U/√[gL]~/=0.5, where L is the hull ship length. PMID:23745883

  3. Effect of Chamfer Angle on the Calibration Curves of Five Hole Probes

    Directory of Open Access Journals (Sweden)

    Nekkanti Sitaram

    2014-01-01

    Full Text Available Five hole probes are extensively used for measurement of total and static pressures, flow angles, velocity and its components in turbomachinery, and other aerodynamic flows. Their operating range is usually limited to 30–40° depending on the type of the probe head. The chamfer angle of the probe is usually taken around 45°. Recent studies on three hole probes have shown that 30° chamfer angle is desirable for unsteady flow measurements. Hence the present investigation is undertaken to find the optimum chamfer angle of five-hole probes. A special five-hole probe of 9.6 mm head diameter and 3 mm diameter pressure take off tubes was designed and fabricated. The large size of the probe was chosen to minimize machining inaccuracies. The probe chamfer angle was varied from 30° to 60° in 5° steps. For each of the chamfer angles, the probe was calibrated in the range of −30° to +30° in 5° interval and the calibration curves are presented. In addition the sensitivities of the calibration coefficients are determined. It is concluded that five-hole probe with a chamfer angle 30° has large operating range, while five-hole probe with a chamfer angle of 50° has good sensitivity.

  4. A fringe shadow method for measuring flapping angle and torsional angle of a dragonfly wing

    Science.gov (United States)

    Zeng, Lijiang; Matsumoto, Hirokazu; Kawachi, Keiji

    1996-05-01

    A fringe shadow (FS) method was developed for measuring the flapping angle and torsional angle of a dragonfly wing during beating motion. This new method involves two sets of fringe patterns projected onto the wing from orthogonal directions. The torsional angle is determined using the length of the shadow of the wing chord that is cast by the two sets of fringe patterns. The flapping angle is determined using the shadowgraph of the wing projected by a laser. The advantages of the FS method are its capability (i) to measure the flapping angle and torsional angle of a dragonfly wing simultaneously using only one high-speed camera and (ii) to recognize the spanwise position of a section from the number of fringes, without having to use diffuse marks that are common in current methods. The resolution of the FS method can be changed easily by adjusting the fringe spacing. The measurement results for the torsional angle and flapping angle of a dragonfly wing prove the effectiveness of the FS method in studying the flight performance of dragonflies.

  5. Bank Angle of a V-Type 12-Cylinder Engine

    Science.gov (United States)

    Ito, Norio; Nakagawa, Akihito; Kitamura, Ryuji

    As the automobile engine advances towards higher performance and higher power, the increase in displacement and the number of cylinders in the engine has led to larger engines. As a result, the need for rigidity countermeasures and reductions in size and weight have brought about the switch from in-line type engines to V-type engines. Currently, most of the V-type automobile engines produced have six or eight cylinders, and some large passenger cars produced in Europe and America have V-type engines with 10 or 12 cylinders. The bank angles of engines in these passenger are almost fixed based on the cylinder number. Therefore, the form of the V-type engine is limited according to the number of cylinders. The present study examines the bank angle of a V-12 engine by performing a detailed analysis of the relationship between the cylinder arrangement and the exciting moment. The goal of the present study is to find a bank angle that has as of yet not been applied to the V-type engine so that the layouts of the absorption and exhaust systems, as well as the attached apparatuses, can be reconfigured.

  6. High angle of attack aerodynamics subsonic, transonic, and supersonic flows

    CERN Document Server

    Rom, Josef

    1992-01-01

    The aerodynamics of aircraft at high angles of attack is a subject which is being pursued diligently, because the modern agile fighter aircraft and many of the current generation of missiles must perform well at very high incidence, near and beyond stall. However, a comprehensive presentation of the methods and results applicable to the studies of the complex aerodynamics at high angle of attack has not been covered in monographs or textbooks. This book is not the usual textbook in that it goes beyond just presenting the basic theoretical and experimental know-how, since it contains reference material to practical calculation methods and technical and experimental results which can be useful to the practicing aerospace engineers and scientists. It can certainly be used as a text and reference book for graduate courses on subjects related to high angles of attack aerodynamics and for topics related to three-dimensional separation in viscous flow courses. In addition, the book is addressed to the aerodynamicist...

  7. Vehicle Sideslip Angle Estimation Based on Hybrid Kalman Filter

    Directory of Open Access Journals (Sweden)

    Jing Li

    2016-01-01

    Full Text Available Vehicle sideslip angle is essential for active safety control systems. This paper presents a new hybrid Kalman filter to estimate vehicle sideslip angle based on the 3-DoF nonlinear vehicle dynamic model combined with Magic Formula tire model. The hybrid Kalman filter is realized by combining square-root cubature Kalman filter (SCKF, which has quick convergence and numerical stability, with square-root cubature based receding horizon Kalman FIR filter (SCRHKF, which has robustness against model uncertainty and temporary noise. Moreover, SCKF and SCRHKF work in parallel, and the estimation outputs of two filters are merged by interacting multiple model (IMM approach. Experimental results show the accuracy and robustness of the hybrid Kalman filter.

  8. Atomistic aspects of crack propagation along high angle grain boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Farkas, D. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Materials Science and Engineering

    1997-12-31

    The author presents atomistic simulations of the crack tip configuration near a high angle {Sigma} = 5 [001](210) symmetrical tilt grain boundary in NiAl. The simulations were carried out using molecular statics and embedded atom (EAM) potentials. The cracks are stabilized near a Griffith condition involving the cohesive energy of the grain boundary. The atomistic configurations of the tip region are different in the presence of the high angle grain boundary than in the bulk. Three different configurations of the grain boundary were studied corresponding to different local compositions. It was found that in ordered NiAl, cracks along symmetrical tilt boundaries show a more brittle behavior for Al rich boundaries than for Ni-rich boundaries. Lattice trapping effects in grain boundary fracture were found to be more significant than in the bulk.

  9. XFEL OSCILLATOR SIMULATION INCLUDING ANGLE-DEPENDENT CRYSTAL REFLECTIVITY

    Energy Technology Data Exchange (ETDEWEB)

    Fawley, William; Lindberg, Ryan; Kim, K-J; Shvyd' ko, Yuri

    2010-08-23

    The oscillator package within the GINGER FEL simulation code has now been extended to include angle-dependent reflectivity properties of Bragg crystals. Previously, the package was modified to include frequencydependent reflectivity in order to model x-ray FEL oscillators from start-up from shot noise through to saturation. We present a summary of the algorithms used for modeling the crystal reflectivity and radiation propagation outside the undulator, discussing various numerical issues relevant to the domain of high Fresnel number and efficient Hankel transforms. We give some sample XFEL-O simulation results obtained with the angle-dependent reflectivity model, with particular attention directed to the longitudinal and transverse coherence of the radiation output.

  10. Gaia on-board metrology: basic angle and best focus

    CERN Document Server

    Mora, A; Brown, A G A; Busonero, D; Carminati, L; Carrasco, J M; Chassat, F; Erdmann, M; Gielesen, W L M; Jordi, C; Katz, D; Kohley, R; Lindegren, L; Loeffler, W; Marchal, O; Panuzzo, P; Seabroke, G; Sahlmann, J; Serpell, E; Serraller, I; van Leeuwen, F; van Reeven, W; Dool, T C van den; Vosteen, L L A

    2014-01-01

    The Gaia payload ensures maximum passive stability using a single material, SiC, for most of its elements. Dedicated metrology instruments are, however, required to carry out two functions: monitoring the basic angle and refocusing the telescope. Two interferometers fed by the same laser are used to measure the basic angle changes at the level of $\\mu$as (prad, micropixel), which is the highest level ever achieved in space. Two Shack-Hartmann wavefront sensors, combined with an ad-hoc analysis of the scientific data are used to define and reach the overall best-focus. In this contribution, the systems, data analysis, procedures and performance achieved during commissioning are presented

  11. Variable Angle of SRG for Wind Energy Control Application

    Directory of Open Access Journals (Sweden)

    Maged N. F. Nashed

    2015-02-01

    Full Text Available Switched reluctance machine has various desirable features, which comes from its simple construction. They are the wide speed range, high temperature operation and small moment of inertia. There are many control variables, such as: firing angles, reference current, speed and voltage. This paper presents a nonlinear model of 6/4 Switched Reluctance Generator (SRG with two converter (one with generator side and other with grid side based on wind Energy system. This system provides a new approach to maximize the amount of power generated. Closed loop control with based PI current Control model is used. A Power converter in SRG can be produced maximum power efficiency and minimize the ripple contents in the output of SRG depend on the converter angles. A second power converter namely PI based controlled PWM inverter is used to interface the machine to the Grid. This system proposed feasibility and validity are simulated on MATLAB/SIMULINK.

  12. TEST METHOD FOR SINGLE INTERIOR RIGHT ANGLE IN A CORNER CUBE PRISM

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new test method for single interior right angle in a corner cube prism is presented. Some key points and parameters are analyzed and derived. The advantage of this method is concluded by comparing with some current conventional methods.

  13. Angles et grandeur d'Euclide à Kamal al-Din al-Farisi

    CERN Document Server

    Rashed, Roshdi

    2015-01-01

    This is the first comprehensive treatment of the history of the angle from Euclid to classical Arabic mathematics. The volume presents critically edited texts, with translations and commentaries, of Greek and Arabic philosophers and mathematicians including Euclid, Simplicius, etc.

  14. Publication guidelines for structural modelling of small-angle scattering data from biomolecules in solution.

    Science.gov (United States)

    Jacques, David A; Guss, J Mitchell; Svergun, Dmitri I; Trewhella, Jill

    2012-06-01

    Small-angle scattering is becoming a mainstream technique for structural molecular biology. As such, it is important to establish guidelines for publication that will ensure that there is adequate reporting of the data and its treatment so that reviewers and readers can independently assess the quality of the data and the basis for any interpretations presented. This article presents a set of preliminary guidelines that emerged after consultation with the IUCr Commission on Small-Angle Scattering and other experts in the field and discusses the rationale for their application. At the 2011 Congress of the IUCr in Madrid, the Commission on Journals agreed to adopt these preliminary guidelines for the presentation of biomolecular structures from small-angle scattering data in IUCr publications. Here, these guidelines are outlined and the reasons for standardizing the way in which small-angle scattering data are presented.

  15. What’s your angle? Using sun angle and look angle to improve carbon flux estimates from optical remote sensing. (Invited)

    Science.gov (United States)

    Gamon, J. A.

    2009-12-01

    Most optical remote sensing remains focused on single-pass nadir views near solar noon, yet optical signals related to carbon uptake (physiological retrievals) are strongly influenced by sun and look angle. Additionally, a long history of remote sensing research into these angular effects (e.g. BRDF studies) indicate a strong angular dependence of vegetation reflectance signatures that clearly affect our ability to model carbon exchange using vegetation indices derived from remote sensing. The structural and physiological aspects of these angular effects have not always been treated in an integrated way within the remote sensing or carbon modeling communities. This presentation will review recent findings suggesting that consideration of combined physiological and structural aspects of angular effects can improve physiological retrievals of optical signals related to biosphere-atmosphere carbon exchange. Using several vegetation indices (NDVI, PRI and WBI) as examples, this presentation will offer suggestions for how carbon flux models can benefit from further consideration of sun and look angle effects in optical remote sensing. Key challenges for further research and suggestions for operational solutions will also be presented.

  16. Small Angle Light Scattering by Biological Objects

    International Nuclear Information System (INIS)

    In this paper the small angle laser radiation scattering by the particles of different shape and size is analyzed. Experimental results and theoretical calculations show that after ejection from bacteriophage DNA forms the scattering medium consisted of quasi-spherical elements with radius of R⁓10λ0. (author)

  17. A Method for Measuring a Plane Angle.

    Science.gov (United States)

    Roberts, George D.; Roberts, G. Gilbert

    1978-01-01

    Derivation of formulas and example problems for determining the size of a plane angle are given to help in drafting work. The authors state that a small hand calculator will provide greater accuracy in solving these problems than a protractor. (MF)

  18. Status of the CDF small angle spectrometer

    International Nuclear Information System (INIS)

    During the 1987 Tevatron collider period the CDF small angle spectrometer system was partially installed and elastic scattering events were recorded in a special high-β run. The design and physics goals of this system are described and results from an analysis of the elastic scattering data are discussed

  19. Surdez súbita unilateral como manifestação de schwannoma vestibular: relato de caso Sudden deafness as a presenting symptom of acoustic neuroma: case report

    Directory of Open Access Journals (Sweden)

    Sérgio Marquez Nascentes

    2007-10-01

    Full Text Available O schwannoma vestibular, também conhecido como neuroma ou neurinoma do acústico, é o tumor mais freqüente do ângulo pontocerebelar correspondendo a aproximadamente a 9% de todos os tumores intracranianos. APRESENTAÇÃO DO CASO: Os autores apresentam um relato de caso de surdez súbita e zumbido unilateral com melhora dos sintomas através de tratamento clínico com Prednisona e Pentoxifilina e posterior diagnóstico por exame de imagem de schwannoma vestibular. DISCUSSÃO: A surdez súbita pode ser descrita como uma perda neurossensorial abrupta e intensa. Costuma ser acima de 30 dB, em três ou mais freqüências contíguas e se desenvolve em menos de três dias. CONCLUSÃO: É de grande importância a pesquisa da etiologia nos casos de surdez súbita para a boa condução do caso e orientação terapêutica.Vestibular schwannoma, also known as acoustic neurinoma, is the most frequent tumor of the cerebellopontine angle, and represents 9% of all intracranial tumors. CASE REPORT: The authors report a case of sudden deafness with unilateral tinnitus. The patients responded to therapy with Prednisone and Pentoxifylline after the diagnosis of acoustic neurinoma by imaging exams. DISCUSSION: Sudden deafness can be described as an intense and abrupt sensorineural loss. Usually it is higher than 30 dB at three or more frequencies and develops in less than three days. CONCLUSION: Investigation of the etiology of sudden deafness is extremely important to establish the adequate strategy for the case.

  20. CHARACTERIZATION OF POWDER FLOWABILITY USING MEASUREMENT OF ANGLE OF REPOSE

    Institute of Scientific and Technical Information of China (English)

    D.; Geldart; E.; C.; Abdullah; A.; Hassanpour; L.; C.; Nwoke; I.; Wouters

    2006-01-01

    In response to the need in industry for a quick and reproducible method of measuring the flowability of powders in processes involving transport and storage, the apparently simple idea of measuring angle of repose has been revived. The simple tester first used has evolved over a number of years into the present version which is shown to be capable of handling quite small samples of powders that are even slightly cohesive. Experimental data are presented and results shown to compare consistently with the better known Hausner ratio.

  1. An open-loop technique for angle determination from position encoders

    OpenAIRE

    Benammar, M.; Ben-Brahim, L.; Alhamadi, M.A.; Al-Emadi, N.; Al-Hitmi, M.

    2008-01-01

    The paper presents a novel technique for the determination of the angle from low-frequency quadrature cosinusoidal signals produced, for example, by position sensors. In the presented scheme applied to a resolver, the separately generated constant-frequency sine wave used for exciting the resolver together with an additional cosine wave are used as reference against which the amplitudes of the angle-dependent demodulated resolver sine and cosine signals are compared. At the instant equality b...

  2. Surface properties of dental polymers: measurements of contact angles, roughness and fluoride release

    Directory of Open Access Journals (Sweden)

    Fátima Namen

    2008-09-01

    Full Text Available OBJECTIVE: Earlier studies on some dental materials measured roughness and/or contact angles or fluoride release separately. In the present study, five dental polymers were investigated to ascertain their contact angles, wettability, roughness, and fluoride release in dry or wet conditions. METHODS: Samples for 5 materials were prepared and stored dry or wet in deionized water pH 6.8. Samples were submitted to finishing/polishing procedures, and the measurements in Goniometer, roughness (µm and fluoride analysis RESULTS AND CONCLUSIONS: Except for the Ariston pHc, all the materials displayed high contact angles when measured with water, showing hydrophobic characteristics. Roughness changed the contact angles, especially those of Ariston (α < 0.05. Fluoride did not modify the contact angles, but increased the roughness of the finished material.

  3. Optimum Design of Highway Excavation Slope Angle: Evidence from Dawu Section of Jingzhu Highway

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The optimum design of the highway excavation slope angle is one of the most important problems to the highway construction and to the slope improvement. The Dawu Section of Jingzhu (Beijing-Zhuhai) Highway is taken as an example to illustrate the study method for excavation slope angle design.The analysis of the engineering condition from different angles with different factors shows that the stability of the slope is calculated by using residual pushing force and the Sarma method. Then the sensitive analysis of the slope stability is conducted by using residual pushing force method. Finally, the optimum angle of design is presented on the precondition of ensuring the whole stability of slope and the economic reasonability. The study results show that the most sensitive factors are the shear strength parameter and t he seismic force, and that the optimum excavation slope angle is 60°.``

  4. A new architecture for self-organized silicon nanowire growth integrated on a left angle 100 right angle silicon substrate

    Energy Technology Data Exchange (ETDEWEB)

    Buttard, D. [Universite Joseph Fourier/IUT-1, Grenoble (France); David, T.; Gentile, P. [CEA-Grenoble/SiNaPS-MINATEC, Grenoble (France); Hertog, M. den; Rouviere, J.L. [CEA-Grenoble/LEMMA-MINATEC, Grenoble (France); Baron, T. [CNRS/LTM, Grenoble (France); Ferret, P. [CEA-DRT/CEA-Grenoble/DOPT, Grenoble (France)

    2008-07-15

    A lithography-independent method for achieving self-organized growth of silicon nanowires by means of a Chemical-Vapor-Deposition process is investigated using a nanoporous alumina template on a left angle 100 right angle oriented silicon substrate. The position of the nanowires is determined by the location of gold colloids, acting as catalysts, which are initially deposited at the bottom of the pores over large areas of the sample. The direction of growth is guided by the pore axis, which is perpendicular to the silicon substrate surface. Results from scanning and transmission electron microscopy are presented and discussed. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Mandibular Angle Fractures: Comparison of One Miniplate vs. Two Miniplates

    Directory of Open Access Journals (Sweden)

    Saeed Hajmohammadi

    2013-01-01

    Full Text Available Background: Monocortical miniplate fixation is an accepted and reliable method for internal fixation of mandibular angle fractures. Although placement of a second miniplate may theoretically provide more stability; however, the clinical importance of this issue remains controversial.Objectives: The present study assessed the postoperative complications and outcomes associated with the fixation of mandibular angle fractures using 1 and 2 miniplates in patients with favorable mandibular angle fractures.Patients and Methods: A prospective study of 87 patients (73 males, 14 females with favorable mandibular angle fractures was done. In the first group, a 4-hole miniplate was placed at the superior border through an intraoral approach. In group 2, patients were treated with 2 miniplates, one placed at the superior border (similar to group 1 and the other on the lateral aspect of the angle at the inferior border through an intraoral and transcutaneous approach using a trocar. Postoperative complications including malocclusion, malunion and sensory disturbances associated with surgery, additional maxillomandibular fixation (MMF by means of an arch bar and wires for a longer period (for delayed union and infection were assessed in patients of both groups up to 12 months postoperatively. The data were analyzed using the chi-square test.Results: In the single miniplate group, 25 patients showed lip numbness associated with surgery (55.6%, 22 patients required additional use of MMF (48.9% and 3 patients developed infections (6.7%. In the double miniplate group 20 patients showed lip numbness associated with surgery (47.6%, 18 patients required additional use of MMF (42.9% and 1 patient developed infection (2.4%. None of the patients in either group showed malocclusion or malunion. No significant difference was observed between the groups regarding overall complication rate.Conclusions: In this study, use of one miniplate or two miniplates for treatment of

  6. Spirality: A Noval Way to Measure Spiral Arm Pitch Angle

    Science.gov (United States)

    Shields, Douglas W.; Boe, Benjamin; Henderson, Casey L.; Hartley, Matthew; Davis, Benjamin L.; Pour Imani, Hamed; Kennefick, Daniel; Kennefick, Julia D.

    2015-01-01

    We present the MATLAB code Spirality, a novel method for measuring spiral arm pitch angles by fitting galaxy images to spiral templates of known pitch. For a given pitch angle template, the mean pixel value is found along each of typically 1000 spiral axes. The fitting function, which shows a local maximum at the best-fit pitch angle, is the variance of these means. Error bars are found by varying the inner radius of the measurement annulus and finding the standard deviation of the best-fit pitches. Computation time is typically on the order of 2 minutes per galaxy, assuming at least 8 GB of working memory. We tested the code using 128 synthetic spiral images of known pitch. These spirals varied in the number of spiral arms, pitch angle, degree of logarithmicity, radius, SNR, inclination angle, bar length, and bulge radius. A correct result is defined as a result that matches the true pitch within the error bars, with error bars no greater than ±7°. For the non-logarithmic spiral sample, the correct answer is similarly defined, with the mean pitch as function of radius in place of the true pitch. For all synthetic spirals, correct results were obtained so long as SNR > 0.25, the bar length was no more than 60% of the spiral's diameter (when the bar was included in the measurement), the input center of the spiral was no more than 6% of the spiral radius away from the true center, and the inclination angle was no more than 30°. The synthetic spirals were not deprojected prior to measurement. The code produced the correct result for all barred spirals when the measurement annulus was placed outside the bar. Additionally, we compared the code's results against 2DFFT results for 203 visually selected spiral galaxies in GOODS North and South. Among the entire sample, Spirality's error bars overlapped 2DFFT's error bars 64% of the time. For those galaxies in which Source code is available by email request from the primary author.

  7. CT patellar cortex tilt angle: A radiological method to measure patellar tilt

    International Nuclear Information System (INIS)

    Background/Objectives: the role of patellar tilt in the anterior knee pain is indisputable. Traditionally. the lateral patello-femoral angle of Laurin has been defined in both the axial view and CT images for measuring the tilt of patella. We present a new angle. which is independent of the morphology of patella and directly relates to clinical assessment of the tilt. which is appreciated from palpation of the edges of the patella. Patients and Methods: 38 patients with anterior knee pain and forty normal control subjects were examined using CT scan of patello-femoral joint in 15 degrees of knee flexion. The amount of lateral patellar tilt was quantitatively assessed using the lateral patello-femoral angle, as described by Laurin et al, and the newly defined patellar cortex tilt angle. This angle is subtended by the line drawn along the posterior femoral condyles and the one parallel to the subchondral bone of patellar cortex. The fifteen-degree tilt was taken as normal cut-off point for patellar cortex tilt angle in the control group. Results: in patients, the average tilt of patella. using the patellar cortex tilt angle was 15.26 versus 7.05 in the control group. Using Student's t test, the difference between the two means was significant (P<0.001). The sensitivity and specificity of patellar cortex tilt angle were 40 and 90 percent, respectively There was a moderate agreement between our presented test and the lateral tilt angle test (kappa=0.40. P<0.001). Conclusion: our results indicate that patellar tilt can also be detected using patellar cortex tilt angle. We need more specific studies ta determine the validity of the test

  8. High-speed reference-beam-angle control technique for holographic memory drive

    Science.gov (United States)

    Yamada, Ken-ichiro; Ogata, Takeshi; Hosaka, Makoto; Fujita, Koji; Okuyama, Atsushi

    2016-09-01

    We developed a holographic memory drive for next-generation optical memory. In this study, we present the key technology for achieving a high-speed transfer rate for reproduction, that is, a high-speed control technique for the reference beam angle. In reproduction in a holographic memory drive, there is the issue that the optimum reference beam angle during reproduction varies owing to distortion of the medium. The distortion is caused by, for example, temperature variation, beam irradiation, and moisture absorption. Therefore, a reference-beam-angle control technique to position the reference beam at the optimum angle is crucial. We developed a new optical system that generates an angle-error-signal to detect the optimum reference beam angle. To achieve the high-speed control technique using the new optical system, we developed a new control technique called adaptive final-state control (AFSC) that adds a second control input to the first one derived from conventional final-state control (FSC) at the time of angle-error-signal detection. We established an actual experimental system employing AFSC to achieve moving control between each page (Page Seek) within 300 µs. In sequential multiple Page Seeks, we were able to realize positioning to the optimum angles of the reference beam that maximize the diffracted beam intensity. We expect that applying the new control technique to the holographic memory drive will enable a giga-bit/s-class transfer rate.

  9. Experimental Validation of the Invariance of Electrowetting Contact Angle Saturation

    NARCIS (Netherlands)

    Chevalliot, S.; Dhindsa, M.; Kuiper, S.; Heikenfeld, J.

    2011-01-01

    Basic electrowetting theory predicts that a continued increase in applied voltage will allow contact angle modulation to zero degrees. In practice, the effect of contact angle saturation has always been observed to limit the contact angle modulation, often only down to a contact angle of 60 to 70°.

  10. The favourable large misorientation angle grain boundaries in graphene.

    Science.gov (United States)

    Zhang, Xiuyun; Xu, Ziwei; Yuan, Qinghong; Xin, John; Ding, Feng

    2015-12-21

    A grain boundary (GB) in graphene is a linear defect between two specifically oriented graphene edges, whose title angles are denoted as θ1 and θ2, respectively. Here we present a systematic theoretical study on the structure and stability of GBs in graphene as a function of the misorientation angle, Φ = (θ1-θ2) and the GB orientation in multi-crystalline graphene, which is denoted by Θ = (θ1 + θ2). It is surprising that although the number of disorders of the GB, i.e., the pentagon-heptagon pairs (5|7s), reaches the maximum at Φ∼ 30°, the GB formation energy versus the Φ curve reaches a local minimum. The subsequent M-shape of the Efvs. the Φ curve is due to the strong cancellation of the local strains around 5|7 pairs by the "head-to-tail" formation. This study successfully explains many previously observed experimental puzzles, such as the multimodal distribution of GBs and the abundance of GB misorientation angles of ∼30°. Besides, this study also showed that the formation energy of GBs is less sensitive to Θ, although the twin boundaries are slightly more stable than others. PMID:26568448

  11. Sparse Representation Based SAR Vehicle Recognition along with Aspect Angle

    Directory of Open Access Journals (Sweden)

    Xiangwei Xing

    2014-01-01

    Full Text Available As a method of representing the test sample with few training samples from an overcomplete dictionary, sparse representation classification (SRC has attracted much attention in synthetic aperture radar (SAR automatic target recognition (ATR recently. In this paper, we develop a novel SAR vehicle recognition method based on sparse representation classification along with aspect information (SRCA, in which the correlation between the vehicle’s aspect angle and the sparse representation vector is exploited. The detailed procedure presented in this paper can be summarized as follows. Initially, the sparse representation vector of a test sample is solved by sparse representation algorithm with a principle component analysis (PCA feature-based dictionary. Then, the coefficient vector is projected onto a sparser one within a certain range of the vehicle’s aspect angle. Finally, the vehicle is classified into a certain category that minimizes the reconstruction error with the novel sparse representation vector. Extensive experiments are conducted on the moving and stationary target acquisition and recognition (MSTAR dataset and the results demonstrate that the proposed method performs robustly under the variations of depression angle and target configurations, as well as incomplete observation.

  12. Angle-resolved effective potentials for disk-shaped molecules

    International Nuclear Information System (INIS)

    We present an approach for calculating coarse-grained angle-resolved effective pair potentials for uniaxial molecules. For integrating out the intramolecular degrees of freedom we apply umbrella sampling and steered dynamics techniques in atomistically-resolved molecular dynamics (MD) computer simulations. Throughout this study we focus on disk-like molecules such as coronene. To develop the methods we focus on integrating out the van der Waals and intramolecular interactions, while electrostatic charge contributions are neglected. The resulting coarse-grained pair potential reveals a strong temperature and angle dependence. In the next step we fit the numerical data with various Gay-Berne-like potentials to be used in more efficient simulations on larger scales. The quality of the resulting coarse-grained results is evaluated by comparing their pair and many-body structure as well as some thermodynamic quantities self-consistently to the outcome of atomistic MD simulations of many-particle systems. We find that angle-resolved potentials are essential not only to accurately describe crystal structures but also for fluid systems where simple isotropic potentials start to fail already for low to moderate packing fractions. Further, in describing these states it is crucial to take into account the pronounced temperature dependence arising in selected pair configurations due to bending fluctuations

  13. The favourable large misorientation angle grain boundaries in graphene.

    Science.gov (United States)

    Zhang, Xiuyun; Xu, Ziwei; Yuan, Qinghong; Xin, John; Ding, Feng

    2015-12-21

    A grain boundary (GB) in graphene is a linear defect between two specifically oriented graphene edges, whose title angles are denoted as θ1 and θ2, respectively. Here we present a systematic theoretical study on the structure and stability of GBs in graphene as a function of the misorientation angle, Φ = (θ1-θ2) and the GB orientation in multi-crystalline graphene, which is denoted by Θ = (θ1 + θ2). It is surprising that although the number of disorders of the GB, i.e., the pentagon-heptagon pairs (5|7s), reaches the maximum at Φ∼ 30°, the GB formation energy versus the Φ curve reaches a local minimum. The subsequent M-shape of the Efvs. the Φ curve is due to the strong cancellation of the local strains around 5|7 pairs by the "head-to-tail" formation. This study successfully explains many previously observed experimental puzzles, such as the multimodal distribution of GBs and the abundance of GB misorientation angles of ∼30°. Besides, this study also showed that the formation energy of GBs is less sensitive to Θ, although the twin boundaries are slightly more stable than others.

  14. Impact Angle Control of Interplanetary Shock Geoeffectiveness: A Statistical Study

    CERN Document Server

    Oliveira, D M

    2015-01-01

    We present a survey of interplanetary (IP) shocks using WIND and ACE satellite data from January 1995 to December 2013 to study how IP shock geoeffectiveness is controlled by IP shock impact angles. A shock list covering one and a half solar cycle is compiled. The yearly number of IP shocks is found to correlate well with the monthly sunspot number. We use data from SuperMAG, a large chain with more than 300 geomagnetic stations, to study geoeffectiveness triggered by IP shocks. The SuperMAG SML index, an enhanced version of the familiar AL index, is used in our statistical analysis. The jumps of the SML index triggered by IP shock impacts on the Earth's magnetosphere is investigated in terms of IP shock orientation and speed. We find that, in general, strong (high speed) and almost frontal (small impact angle) shocks are more geoeffective than inclined shocks with low speed. The strongest correlation (correlation coefficient R = 0.70) occurs for fixed IP shock speed and varying the IP shock impact angle. We ...

  15. Angle-resolved effective potentials for disk-shaped molecules

    Energy Technology Data Exchange (ETDEWEB)

    Heinemann, Thomas, E-mail: thomas.heinemann@tu-berlin.de; Klapp, Sabine H. L., E-mail: klapp@physik.tu-berlin.de [Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Palczynski, Karol, E-mail: karol.palczynski@helmholtz-berlin.de; Dzubiella, Joachim, E-mail: joachim.dzubiella@helmholtz-berlin.de [Institut für Physik, Humboldt Universität zu Berlin, Newtonstraße 15, 12489 Berlin (Germany); Helmholtz Zentrum Berlin (HZB), Institute of Soft Matter and Functional Materials, Hahn-Meitner Platz 1, 14109 Berlin (Germany)

    2014-12-07

    We present an approach for calculating coarse-grained angle-resolved effective pair potentials for uniaxial molecules. For integrating out the intramolecular degrees of freedom we apply umbrella sampling and steered dynamics techniques in atomistically-resolved molecular dynamics (MD) computer simulations. Throughout this study we focus on disk-like molecules such as coronene. To develop the methods we focus on integrating out the van der Waals and intramolecular interactions, while electrostatic charge contributions are neglected. The resulting coarse-grained pair potential reveals a strong temperature and angle dependence. In the next step we fit the numerical data with various Gay-Berne-like potentials to be used in more efficient simulations on larger scales. The quality of the resulting coarse-grained results is evaluated by comparing their pair and many-body structure as well as some thermodynamic quantities self-consistently to the outcome of atomistic MD simulations of many-particle systems. We find that angle-resolved potentials are essential not only to accurately describe crystal structures but also for fluid systems where simple isotropic potentials start to fail already for low to moderate packing fractions. Further, in describing these states it is crucial to take into account the pronounced temperature dependence arising in selected pair configurations due to bending fluctuations.

  16. Controlling the crossing angle in the SSC [Superconducting Super Collider

    International Nuclear Information System (INIS)

    The colliding beams in the SSC must cross at a small angle, so that when the bunches pass each other away from the interaction point (IP), they are sufficiently separated to avoid disruptive beam-beam forces. However, the crossing angle is so small that the adjacent quadrupoles must be common to both beams. Only after passing through four common quadrupoles on each side of the IP, are the beams split by vertical dipoles into separate beamlines. In order to make the closed orbits of the two beams cross at a definite angle at the IP (within a range up to 150 μrad), a series of correction dipoles are placed in the insertions. If these dipoles are excited in such a way as to control the closed orbits alone, the dispersion will be mismatched, reaching values of up to 50 cm in the arcs. This mismatch is due to the closed orbit displacements in the interaction region (IR) quadrupoles, causing them to act as bending magnets. Therefore, both the closed orbit and dispersion must be matched simultaneously. Solutions to this problem are presented. 6 figs

  17. Dynamic-angle spinning and double rotation of quadrupolar nuclei

    International Nuclear Information System (INIS)

    Nuclear magnetic resonance (NMR) spectroscopy of quadrupolar nuclei is complicated by the coupling of the electric quadrupole moment of the nucleus to local variations in the electric field. The quadrupolar interaction is a useful source of information about local molecular structure in solids, but it tends to broaden resonance lines causing crowding and overlap in NMR spectra. Magic- angle spinning, which is routinely used to produce high resolution spectra of spin-1/2 nuclei like carbon-13 and silicon-29, is incapable of fully narrowing resonances from quadrupolar nuclei when anisotropic second-order quadrupolar interactions are present. Two new sample-spinning techniques are introduced here that completely average the second-order quadrupolar coupling. Narrow resonance lines are obtained and individual resonances from distinct nuclear sites are identified. In dynamic-angle spinning (DAS) a rotor containing a powdered sample is reoriented between discrete angles with respect to high magnetic field. Evolution under anisotropic interactions at the different angles cancels, leaving only the isotropic evolution of the spin system. In the second technique, double rotation (DOR), a small rotor spins within a larger rotor so that the sample traces out a complicated trajectory in space. The relative orientation of the rotors and the orientation of the larger rotor within the magnetic field are selected to average both first- and second-order anisotropic broadening. The theory of quadrupolar interactions, coherent averaging theory, and motional narrowing by sample reorientation are reviewed with emphasis on the chemical shift anisotropy and second-order quadrupolar interactions experienced by half-odd integer spin quadrupolar nuclei. The DAS and DOR techniques are introduced and illustrated with application to common quadrupolar systems such as sodium-23 and oxygen-17 nuclei in solids

  18. Water Past and Present

    Science.gov (United States)

    2008-01-01

    This image of sulfate and water ice deposits in the Olympia Undae region of Mars was taken by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) at 2213 UTC on October 2, 2006 (6:13 p.m. EDT) near 81.6 degrees north latitude, 188.9 degrees east longitude. CRISM's image was taken in 544 colors covering 0.36-3.92 micrometers, and shows features as small as 20 meters (66 feet) across. Olympia Undae is a large dune field that stretches some 1,100 kilometers (684 miles) across the northern polar region of Mars, just south of the ice cap. The region holds a vast expanse of complex, shifting dunes and is best described as a sand sea or erg similar to the Sahara. The two images above provide interesting clues into Mars' history by revealing the planet's wet past and frozen present. The left image is an infrared, false-color image that reveals dark-colored dunes overlying a lighter substrate. Spectral data from CRISM and its sister instrument OMEGA suggest similar compositions of these dunes and the dark basal, or lowermost, unit of the north polar layered deposits. HIRISE images revealed cross-bedding (crossed layers that are oriented at a different angle to the main layer) in this dark unit. On Earth, cross-bedded sediments can form in both windy and watery environments. The dark polar basal unit on Mars is interpreted as a sand sheet underlying and pre-dating the ice, and now being eroded to dunes by the Martian winds. The mineralogy of the Olympia Undae region holds a record of past water. CRISM spectral data (right image) shows that the darker dunes are rich in polyhydrated sulfate (sulfates with more than one water molecule incorporated into each molecule of the mineral). The mineral gypsum is a polyhydrated sulfate, and the most likely constituent in these dunes. The gypsum probably formed by evaporation of ancient, saline water or by aqueous alteration of the silicate portion of the dune material. Areas shaded in red are cover by dust. Blue areas in

  19. Sparse regularization in limited angle tomography

    CERN Document Server

    Frikel, Jürgen

    2011-01-01

    We investigate the reconstruction problem of limited angle tomography. Such problems arise naturally in applications like digital breast tomosynthesis, dental tomography, electron microscopy etc. Since the acquired tomographic data is highly incomplete, the reconstruction problem is severely ill-posed and the traditional reconstruction methods, such as filtered backprojection (FBP), do not perform well in such situations. To stabilize the reconstruction procedure additional prior knowledge about the unknown object has to be integrated into the reconstruction process. In this work, we propose the use of the sparse regularization technique in combination with curvelets. We argue that this technique gives rise to an edge-preserving reconstruction. Moreover, we show that the dimension of the problem can be significantly reduced in the curvelet domain. To this end, we give a characterization of the kernel of limited angle Radon transform in terms of curvelets and derive a characterization of solutions obtained thr...

  20. The Contact Angle in Inviscid Fluid Mechanics

    Indian Academy of Sciences (India)

    P N Shankar; R Kidambi

    2005-05-01

    We show that in general, the specification of a contact angle condition at the contact line in inviscid fluid motions is incompatible with the classical field equations and boundary conditions generally applicable to them. The limited conditions under which such a specification is permissible are derived;however, these include cases where the static meniscus is not flat. In view of this situation, the status of the many `solutions’ in the literature which prescribe a contact angle in potential flows comes into question. We suggest that these solutions which attempt to incorporate a phenomenological, but incompatible, condition are in some, imprecise sense `weak-type solutions’;they satisfy or are likely to satisfy, at least in the limit, the governing equations and boundary conditions everywhere except in the neighbourhood of the contact line. We discuss the implications of the result for the analysis of inviscid flows with free surfaces.

  1. Weak mixing angle measurements at hadron colliders

    CERN Document Server

    Di Simone, Andrea; The ATLAS collaboration

    2015-01-01

    The Talk will cover weak mixing angle measurements at hadron colliders ATLAS and CMS in particular. ATLAS has measured the forward-backward asymmetry for the neutral current Drell Yan process in a wide mass range around the Z resonance region using dielectron and dimuon final states with $\\sqrt{s}$ =7 TeV data. For the dielectron channel, the measurement includes electrons detected in the forward calorimeter which extends the covered phase space. The result is then used to extract a measurement of the effective weak mixing angle. Uncertainties from the limited knowledge on the parton distribution functions in the proton constitute a significant part of the uncertainty and a dedicated study is performed to obtain a PDF set describing W and Z data measured previously by ATLAS. Similar studies from CMS will be reported.

  2. Gaia: focus, straylight and basic angle

    CERN Document Server

    Mora, A; Bombrun, A; Boyadian, J; Chassat, F; Corberand, P; Davidson, M; Doyle, D; Escolar, D; Gielesen, W L M; Guilpain, T; Hernandez, J; Kirschner, V; Klioner, S A; Koeck, C; Laine, B; Lindegren, L; Serpell, E; Tatry, P; Thoral, P

    2016-01-01

    The Gaia all-sky astrometric survey is challenged by several issues affecting the spacecraft stability. Amongst them, we find the focus evolution, straylight and basic angle variations Contrary to pre-launch expectations, the image quality is continuously evolving, during commissioning and the nominal mission. Payload decontaminations and wavefront sensor assisted refocuses have been carried out to recover optimum performance. An ESA-Airbus DS working group analysed the straylight and basic angle issues and worked on a detailed root cause analysis. In parallel, the Gaia scientists have also analysed the data, most notably comparing the BAM signal to global astrometric solutions, with remarkable agreement. In this contribution, a status review of these issues will be provided, with emphasis on the mitigation schemes and the lessons learned for future space missions where extreme stability is a key requirement.

  3. Cognitive models for the concept of angle

    OpenAIRE

    Matos, José Manuel Leonardo de

    1999-01-01

    The instructional models taught in class were similar to the students' models. The teachers addressed angle as a basic-level category, discussed its submodels, clarified the boundaries, and established cognitive reference points. They gradually increased the use of complex metaphors and of several models. The study enriched the characterization of the first two levels of van Hiele theory and demonstrated the value of categorization theory in understanding how our comprehension ...

  4. Black hole microstates from branes at angle

    CERN Document Server

    Pieri, Lorenzo

    2016-01-01

    We derive the leading g_s perturbation of the SUGRA fields generated by a supersymmetric configuration of respectively 1, 2 or 4 D3-branes intersecting at an arbitrary angle via the computation of the string theory disk scattering amplitude of one massless NSNS field interacting with open strings stretched between the branes. The configuration with four branes is expected to be relevant for black hole microstate counting in four dimensions.

  5. Moment-angle complexes from simplicial posets

    CERN Document Server

    Lu, Zhi

    2009-01-01

    We extend the construction of moment-angle complexes to simplicial posets by associating a certain T^m-space Z_S to an arbitrary simplicial poset S on m vertices. Face rings Z[S] of simplicial posets generalise those of simplicial complexes, but have much more complicated algebraic structure. Our primary motivation is to study the face rings Z[S] by topological methods. The space Z_S has many important topological properties of the original moment-angle complex Z_K associated to a simplicial complex K. In particular, we prove that the integral cohomology algebra of Z_S is isomorphic to the Tor-algebra of the face ring Z[S]. This leads directly to a generalisation of Hochster's theorem, expressing the algebraic Betti numbers of the ring Z[S] in terms of the homology of full subposets in S. Finally, we estimate the total amount of homology of Z_S from below by proving the toral rank conjecture for the moment-angle complexes Z_S.

  6. A New Derivation of GRB Jet Opening Angles from the Prompt Gamma-Ray Emission

    CERN Document Server

    Goldstein, Adam; Briggs, Michael S; van der Horst, Alexander J; McBreen, Sheila; Kouveliotou, Chryssa; Connaughton, Valerie; Paciesas, William S; Meegan, Charles A; Bhat, P N; Bissaldi, Elisabetta; Burgess, J Michael; Chaplin, Vandiver; Diehl, Roland; Fishman, Gerald J; Fitzpatrick, Gerard; Foley, Suzanne; Gibby, Melissa; Giles, Misty; Greiner, Jochen; Gruber, David; Guiriec, Sylvain; von Kienlin, Andreas; Kippen, Marc; Rau, Arne; Tierney, Dave; Wilson-Hodge, Colleen

    2011-01-01

    The jet opening angle of gamma-ray bursts (GRBs) is an important parameter for determining the characteristics of the progenitor, and the information contained in the opening angle gives insight into the relativistic outflow and the total energy that is contained in the burst. Unfortunately, a confident inference of the jet opening angle usually requires broadband measurement of the afterglow of the GRB, from the X-ray down to the radio and from minutes to days after the prompt gamma-ray emission, which may be difficult to obtain. For this reason, very few of all detected GRBs have constrained jet angles. We present an alternative approach to derive jet opening angles from the prompt emission of the GRB, given that the GRB has a measurable Epeak and fluence, and which does not require any afterglow measurements. We present the distribution of derived jet opening angles for the first two years of the Fermi Gamma-ray Burst Monitor (GBM) operation, and we compare a number of our derived opening angles to the rep...

  7. 2016 Research Final Presentation

    Energy Technology Data Exchange (ETDEWEB)

    Koskelo, EliseAnne Corinne [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-16

    These are slides which show an example of research at Los Alamos National Laboratory done by E.C. Koskelo to show college professors in the hopes of earning a research position or fellowship position. In summary, this researcher developed a new in-situ technique for the inspection of additively manufactured parts, created an algorithm which can correct "skewed" scans of angular parts/taken at oblique angles, and used AWS to detect hidden defects and thickness changes in aerospace composites.

  8. Optimum angle-cut of collimator for dense objects in high-energy proton radiography

    Science.gov (United States)

    Xu, Hai-Bo; Zheng, Na

    2016-02-01

    The use of minus identity lenses with an angle-cut collimator can achieve high contrast images in high-energy proton radiography. This article presents the principles of choosing the angle-cut aperture of the collimator for different energies and objects. Numerical simulation using the Monte Carlo code Geant4 has been implemented to investigate the entire radiography for the French test object. The optimum angle-cut apertures of the collimators are also obtained for different energies. Supported by NSAF (11176001) and Science and Technology Developing Foundation of China Academy of Engineering Physics (2012A0202006)

  9. Effect of leaning angle of gecko-inspired slanted polymer nanohairs on dry adhesion

    KAUST Repository

    Jeong, Hoon Eui

    2010-01-01

    We present analysis of adhesion properties of angled polymer nanohairs with a wide range of leaning angles from 0° to 45° and ultraviolet (UV)-curable polyurethane acrylate (PUA) materials of two different elastic moduli (19.8 and 320 MPa). It is demonstrated that shear adhesion and adhesion hysteresis can be greatly enhanced by increasing the leaning angle of nanohairs both for soft and hard materials due to increased contact area and reduced structural stiffness. © 2010 American Institute of Physics.

  10. STUDY ON NECK SHAFT ANGLE AND FEMORAL LENGTH OF SOUTH INDIAN FEMURS

    OpenAIRE

    Shakil Mohamad Khan; Shaik Hussain Saheb

    2014-01-01

    Back ground: Femoral nek anteversion describes the angle subtended by the femoral neck with reference to the transcondylar plane of the distal end of the femur and is usually 15° to 45°. This along with the neck shaft angle, hip axis length, femoral neck width influence the risk of femoral neck fracture. Femoral neck anteversion angle has to be taken into consideration when reduction and fixation is selected as a method of treatment. Objectives: The objectives of present study to find out ...

  11. Angle-Resolved Auger Spectroscopy as a Sensitive Access to Vibronic Coupling

    Science.gov (United States)

    Knie, A.; Patanen, M.; Hans, A.; Petrov, I. D.; Bozek, J. D.; Ehresmann, A.; Demekhin, Ph. V.

    2016-05-01

    In the angle-averaged excitation and decay spectra of molecules, vibronic coupling may induce the usually weak dipole-forbidden transitions by the excitation intensity borrowing mechanism. The present complementary theoretical and experimental study of the resonant Auger decay of core-to-Rydberg excited CH4 and Ne demonstrates that vibronic coupling plays a decisive role in the formation of the angle-resolved spectra by additionally involving the decay rate borrowing mechanism. Thereby, we propose that the angle-resolved Auger spectroscopy can in general provide very insightful information on the strength of the vibronic coupling.

  12. Experimental investigation of heat transfer and effectiveness in corrugated plate heat exchangers having different chevron angles

    Science.gov (United States)

    Kılıç, Bayram; İpek, Osman

    2016-06-01

    In this study, heat transfer rate and effectiveness of corrugated plate heat exchangers having different chevron angles were investigated experimentally. Chevron angles of plate heat exchangers are β = 30° and β = 60°. For this purpose, experimentally heating system used plate heat exchanger was designed and constructed. Thermodynamic analysis of corrugated plate heat exchangers having different chevron angles were carried out. The heat transfer rate and effectiveness values are calculated. The experimental results are shown that heat transfer rate and effectiveness values for β = 60° is higher than that of the other. Obtained experimental results were graphically presented.

  13. Pair Creation at Large Inherent Angles

    Energy Technology Data Exchange (ETDEWEB)

    Chen, P.; Tauchi, T.; Schroeder, D.V.; /SLAC

    2007-04-25

    In the next-generation linear colliders, the low-energy e{sup +}e{sup -} pairs created during the collision of high-energy e{sup +}e{sup -} beams would cause potential deleterious background problems to the detectors. At low collider energies, the pairs are made essentially by the incoherent process, where the pair is created by the interaction of beamstrahlung photons on the individual particles in the oncoming beam. This problem was first identified by Zolotarev, et al[1]. At energies where the beamstrahlung parameter {Upsilon} lies approximately in the range 0.6 {approx}< {Upsilon} {approx}< 100, pair creation from the beamstrahlung photons is dominated by a coherent process, first noted by Chen[2]. The seriousness of this pair creation problem lies in the transverse momenta that the pair particles carry when leaving the interaction point (IP) with large angles. One source of transverse momentum is from the kick by the field of the oncoming beam which results in an outcoming angle {theta} {proportional_to} 1/{radical}x, where x is the fractional energy of the particle relative to the initial beam particle energy[2,3]. As was shown in Ref. 131, there in fact exists an energy threshold for the coherent pairs, where x{sub th} {approx}> 1/2{Upsilon}. Thus within a tolerable exiting angle, there exists an upper limit for {Upsilon} where all coherent pairs would leave the detector through the exhaust port[4]. A somewhat different analysis has been done by Schroeder[5]. In the next generation of linear colliders, as it occurs, the coherent pairs can be exponentially suppressed[2] by properly choosing the {Upsilon}({approx}< 0.6). When this is achieved, the incoherent pairs becomes dominant. Since the central issue is the transverse momentum for particles with large angles, we notice that there is another source for it. Namely, when the pair particles are created at low energies, the intrinsic angles of these pairs when produced may already be large. This issue was

  14. Virtual Presenters: Towards Interactive Virtual Presentations

    NARCIS (Netherlands)

    Nijholt, A.; Cappellini, V.; Hemsley, J.

    2005-01-01

    We discuss having virtual presenters in virtual environments that present information to visitors of these environments. Some current research is surveyed and we will look in particular to our research in the context of a virtual meeting room where a virtual presenter uses speech, gestures, pointing

  15. Modified small angle magnetization rotation method in multilayer magnetic microwires

    Science.gov (United States)

    Torrejón, J.; Badini, G.; Pirota, K.; Vázquez, M.

    2007-09-01

    The small angle magnetization rotation (SAMR) technique is a widely used method to quantify magnetostriction in elongated ultrasoft magnetic materials. In the present work, we introduce significant optimization of the method, particularly simplification of the required equipment, profiting of the very peculiar characteristics of a recently introduced family of multilayer magnetic microwires consisting of a soft magnetic core, insulating intermediate layer and a hard magnetic outer layer. The introduced modified SAMR method is used not only to determine the saturation magnetostriction constant of the soft magnetic nucleus but also the magnetoelastic and magnetostatic coupling. This new method has a great potential in multifunctional sensor applications.

  16. Angle-resolved photoemission study of Ag(1 1 1)

    Science.gov (United States)

    Edamoto, K.; Miyazaki, E.; Shimokoshi, K.; Kato, H.

    1990-01-01

    The (1 1 1) face of Ag has been studied by angle-resolved photoemission spectroscopy utilizing synchrotron radiation as the excitation source (25 FIRO method. The peak positions thus determined are used to map the dispersion curves along the lang1 1 1rang (Γ-L) direction. The results show general agreement with calculated band structure, so far as the energy levels and symmetries are concerned. However, it is found that the density of state effect is dominant in the spectra obtained in the present photon energy region. The emission from the Ag 5s, p bands is observed to be broadened due to the indirect transition process.

  17. Geleophysic dysplasia associated with bilateral angle closure glaucoma

    Directory of Open Access Journals (Sweden)

    Murat Sinan Saricaoglu

    2013-01-01

    Full Text Available In this case report, we present occurrence of bilateral angle closure glaucoma in a 9-year-old girl with geleophysic dysplasia. Bilateral YAG laser iridotomy was applied, but intraocular pressure (IOP remained at high levels, necessitating bilateral trabeculectomy with mitomycin C. On her follow-up examinations for 3 years, IOP remained in the mid-20s with no need for further intervention or antiglaucoma medication. There are few reports describing the ocular findings of geleophysic dysplasia in literature. To our knowledge, this is the first case report describing an application of glaucoma surgery and its results at geleophysic dysplasia.

  18. Angle-dependent loop shifts in antiferromagnetic nanoparticles

    Science.gov (United States)

    Mao, Zhongquan; Zhan, Xiaozhi; Chen, Xi

    2016-08-01

    Experimentally hysteresis loop shifts have been widely observed in antiferromagnetic (AF) nanoparticles. Here numerical investigations show that this effect is dependent on the angle between the easy axis of the AF spins and the applied magnetic field in uncompensated nanoparticles. In contrast, the loop shifts disappear in compensated nanoparticles. The results suggest that the uncompensated spins and field directions are essential ingredients to generate loop shifts in AF nanoparticle systems. The present study hints at a possible way to optimize the magnetic performance of AF nanostructures.

  19. Conservative treatment of Angle Class III malocclusion with anterior crossbite

    Directory of Open Access Journals (Sweden)

    João Hélder Ferreira de Aguiar

    2015-08-01

    Full Text Available Angle Class III malocclusion is characterized by anteroposterior dental discrepancy which might be associated or not with skeletal changes. Class III molar relationship is associated with vertical or lingually tipped mandibular incisors and a usually concave profile. These characteristics seriously affect facial esthetics and most frequently are the reason why patients seek orthodontic treatment. This case was presented to the committee of the Brazilian Board of Orthodontics and Facial Orthopedics (BBO as part of the requisites to become a BBO Diplomate.

  20. Fourier domain optical coherence tomography to assess the iridocorneal angle and correlation study in a large Caucasian population

    OpenAIRE

    Fernández-Vigo, José Ignacio; García-Feijóo, Julián; Martínez-de-la-Casa, José María; García-Bella, Javier; Arriola-Villalobos, Pedro; Fernández-Pérez, Cristina; Fernández-Vigo, José Ángel

    2016-01-01

    Background Recently, novel anatomic parameters that can be measured by optical coherence tomography (OCT), have been identified as a more objective and accurate method of defining the iridocorneal angle. The aim of the present study is to measure the iridocorneal angle by Fourier domain (FD) OCT and to identify correlations between angle measurements and subject factors in a large healthy Caucasian population. Methods A cross sectional study was performed in 989 left eyes of 989 healthy subje...

  1. [Correction Multiplicative Effects in Raman Spectra through Vector Angle Transformation].

    Science.gov (United States)

    Yao, Zhi-xiang; Sun, Zeng-qiang; Su, Hui; Yuan, Hong-fu

    2016-02-01

    obtained at different Raman integral times and have remarkable multiplicative effects. In predicting results, the correlation coefficient (r) and the root mean squared error of prediction (RMSEP) from class PLS respectively are 0.911 9 and 0.110 2, and 0.906 0 and 0.100 8 are for the preprocessing by multiplicative scatter correction (MSC). In contrast, r and RMSEP under the VAPLS, presented by this thesis, respectively are 0.998 7 and 0.015 2 and are significantly better than others. The VAPLS has eliminated the multiplicative effects of Raman spectra and improved the accuracy of Raman quantitative analysis and it owes to the preprocessing of the vector angle transformation. PMID:27209742

  2. Research on recognition of ramp angle based on transducer

    Directory of Open Access Journals (Sweden)

    Wenhao GU

    2015-12-01

    Full Text Available Focusing on the recognition of ramp angle, the relationship between the signal of vehicle transducer and real ramp angle is studied. The force change of vehicle on the ramp, and the relationship between the body tilt angle and front and rear suspension scale is discussed. According to the suspension and tire deformation, error angle of the ramp angle is deduced. A mathematical model is established with Matlab/Simulink and used for simulation to generate error curve of ramp angle. The results show that the error angle increases with the increasing of the ramp angle, and the limit value can reach 6.5%, while the identification method can effectively eliminate this error, and enhance the accuracy of ramp angle recognition.

  3. Perceptions of tilt angles of an agricultural tractor.

    Science.gov (United States)

    Görücü, Serap; Cavallo, Eugenio; Murphy, Dennis

    2014-01-01

    A tractor stability simulator has been developed to help study tractor operators' perceptions of angles when the simulator is tilted to the side. The simulator is a trailer-mounted tractor cab equipped with hydraulic lift that can tilt the tractor cabin up to 30 degrees. This paper summarizes data from 82 participants who sat in the simulator while it was tilted. Demographic variables, estimates of tilt angles, and measured tilt angles were collected. The effects of age, gender, tractor driving experience, and frequency of operation on the estimated and measured tilt angles were analyzed. The results showed that about 50% of the participants reported estimations of side tilt angles within ±5 degrees of the actual angles, and nearly the same percentage overestimated the actual side tilt angles. Only a small percentage underestimated the angles. Older, more experienced, and male participants set higher limits on the actual angle at which they felt uncomfortable and would not drive. PMID:24417527

  4. Electromyography-Based Quantitative Representation Method for Upper-Limb Elbow Joint Angle in Sagittal Plane

    OpenAIRE

    Pang, Muye; Guo, Shuxiang; Huang, Qiang; Ishihara, Hidenori; Hirata, Hideyuki

    2015-01-01

    This paper presents a quantitative representation method for the upper-limb elbow joint angle using only electromyography (EMG) signals for continuous elbow joint voluntary flexion and extension in the sagittal plane. The dynamics relation between the musculotendon force exerted by the biceps brachii muscle and the elbow joint angle is developed for a modified musculoskeletal model. Based on the dynamics model, a quadratic-like quantitative relationship between EMG signals and the elbow joint...

  5. Arthrographic study of the Wiberg's CE angle in cadavers of children under 3 years old

    International Nuclear Information System (INIS)

    Forty hip arthrographies in cadavers of children under 3 years of age are presented. The articular relationships of the hip through the definition of the morphology of the proximal femoral epyphysis are evaluated. The location of point 'C' and the evaluation of 'CE' angle in this age group are related. The results of the arthrographic 'CE' osseous angle are compared with Salvati's method and with Massie and Howorth's method. (M.A.C.)

  6. Determination of Load Bearing Capacity for Spatial Joint with Steel Angle Brackets

    Science.gov (United States)

    Sejkot, P.; Ormarsson, S.; Vessby, J.; Kuklík, P.

    2015-11-01

    The design of spatial connections in load bearing timber structures with steel angle brackets has insufficient support in the existing design standards. Therefore, research has been necessary to improve this state of the art. In the current paper an experimental study on two designs of angle brackets is presented and the results from full-scale experiments are compared to numerical and analytical computational models.

  7. Synthesis of functional nanomaterials via colloidal mask templating and glancing angle deposition (GLAD)”

    DEFF Research Database (Denmark)

    Dolatshahi-Pirouz, Alireza; Jensen, Thomas Bo; Vorup-Jensen, Thomas;

    2010-01-01

    We present a simple method for the fabrication of separated brush-like networks with both improved optical and biological properties. The brush networks were fabricated by combing the glancing angle deposition (GLAD) technique with colloidal mask templating. By changing the deposition angle durin...... of multifunctional nanomaterials which could have potential impact on devices where both controlled optical properties and cell surface interactions are needed (for instance controlled cell adhesion on optical biosensor materials)....

  8. Low-angle X-ray scattering from spices

    Energy Technology Data Exchange (ETDEWEB)

    Desouky, O.S. E-mail: omardesouky@yahoo.com; Ashour, Ahmed H.; Abdullah, Mohamed I.; Elshemey, Wael M

    2002-07-01

    Low-angle scattering of X-rays is characterized by the presence of one or more peaks in the forward direction of scattering. These peaks are due to the interference of photons coherently scattered from the molecules of the medium. Thus these patterns are closely linked to the molecular structure of the investigated medium. In this work, low-angle X-ray scattering (LAXS) profiles of five spices; pimpinella anisum (anise), coriandrum sativum (coriander), cuminum cyminum (cumin), foenculum vulgare (fennel) and nigella sativa (nigella or black cumin) are presented after extensive measurements. It is found that all spices exhibit one characteristic peak at a scattering angle around 10 deg. This is equivalent to a value x=0.0565 A{sup -1}, where x=sin({theta}/2)/{lambda}. The full width at half maximum (FWHM) of this peak is found to be characteristic for each type of the investigated spices. The possibility to detect the irradiation of these spices from their LAXS profiles is also examined after 10, 20, 30 and 40 kGy doses of gamma radiation. Except for anise, coriander and cumin at 40 kGy, there are no detectable deviations from the control samples in the scattering profiles of irradiated samples. These results comply with the recommendations of the FDA (US Food and Drug Administration) which defines 30 kGy as the maximum dose for irradiation of spices. The present technique could be used to detect over-irradiation, which causes damage to the molecular structure of some spices.

  9. Determining surface wave arrival angle anomalies

    Science.gov (United States)

    Larson, Erik W. F.; Ekström, Göran

    2002-06-01

    A new method for measuring arrival angles of teleseismic Love and Rayleigh waves is developed. The new method utilizes estimates of surface wave dispersion to create a phase-matched filter to isolate the Love or Rayleigh wave in three-component recordings. The polarization of the filtered wave group is determined in the time domain by application of a variation of the complex polarization method of Vidale [1986]. Orientation, linearity, and ellipticity of particle motion are estimated in several frequency bands to determine the frequency-dependent polarization. The method employs an iterative scheme, by which a predicted Love wave, based on the estimated dispersion and polarization, is subtracted from the three-component data prior to the estimation of Rayleigh wave polarization, and vice versa. The method is applied to an extensive set of Global Seismographic Network data covering the years 1989-1998. Between 4244 and 15,075 measurements are collected for fundamental mode Love and Rayleigh waves at nine different periods (37 to 150 s). Measurement uncertainties are estimated using the statistics of observations for pairwise similar paths and are generally of the order of 15-50% of the total signal, depending on the period and the wave type. Large and azimuthally invariant angle anomalies are documented for several stations and are consistent with misorientation of the horizontal seismometers. Two schemes are employed to determine the misorientations: (1) an azimuthally weighted average at each station, and (2) a joint inversion for seismometer misorientation and globally heterogeneous phase velocities. The determined corrections are robust and correlate well with those reported in earlier studies. Azimuthally varying arrival angle anomalies are shown to agree qualitatively with predictions of wave refraction calculated for recent phase velocity maps, which explain up to 30% of the variance in the new measurements.

  10. Extraction of average neck flexion angle during swallowing in neutral and chin-tuck positions

    Directory of Open Access Journals (Sweden)

    Sejdić Ervin

    2009-10-01

    Full Text Available Abstract Background A common but debated technique in the management of swallowing difficulties is the chin tuck swallow, where the neck is flexed forward prior to swallowing. Natural variations in chin tuck angles across individuals may contribute to the differential effectiveness of the technique. Methodology To facilitate the study of chin tuck angle variations, we present a template tracking algorithm that automatically extracts neck angles from sagittal videos of individuals performing chin tuck swallows. Three yellow markers geometrically arranged on a pair of dark visors were used as tracking cues. Results The algorithm was applied to data collected from 178 healthy participants during neutral and chin tuck position swallows. Our analyses revealed no major influences of body mass index and age on neck flexion angles during swallowing, while gender influenced the average neck angle only during wet swallows in the neutral position. Chin tuck angles seem to be independent of anthropometry and gender in healthy adults, but deserve further study in pathological populations. Conclusion The proposed neck flexion angle extraction algorithm may be useful in future studies where strict participant compliance to swallowing task protocol can be assured.

  11. Contact angle adjustment in equation-of-state-based pseudopotential model.

    Science.gov (United States)

    Hu, Anjie; Li, Longjian; Uddin, Rizwan; Liu, Dong

    2016-05-01

    The single component pseudopotential lattice Boltzmann model has been widely applied in multiphase simulation due to its simplicity and stability. In many studies, it has been claimed that this model can be stable for density ratios larger than 1000. However, the application of the model is still limited to small density ratios when the contact angle is considered. The reason is that the original contact angle adjustment method influences the stability of the model. Moreover, simulation results in the present work show that, by applying the original contact angle adjustment method, the density distribution near the wall is artificially changed, and the contact angle is dependent on the surface tension. Hence, it is very inconvenient to apply this method with a fixed contact angle, and the accuracy of the model cannot be guaranteed. To solve these problems, a contact angle adjustment method based on the geometry analysis is proposed and numerically compared with the original method. Simulation results show that, with our contact angle adjustment method, the stability of the model is highly improved when the density ratio is relatively large, and it is independent of the surface tension. PMID:27301005

  12. Angle gathers in wave-equation imaging for transversely isotropic media

    KAUST Repository

    Alkhalifah, Tariq Ali

    2010-11-12

    In recent years, wave-equation imaged data are often presented in common-image angle-domain gathers as a decomposition in the scattering angle at the reflector, which provide a natural access to analysing migration velocities and amplitudes. In the case of anisotropic media, the importance of angle gathers is enhanced by the need to properly estimate multiple anisotropic parameters for a proper representation of the medium. We extract angle gathers for each downward-continuation step from converting offset-frequency planes into angle-frequency planes simultaneously with applying the imaging condition in a transversely isotropic with a vertical symmetry axis (VTI) medium. The analytic equations, though cumbersome, are exact within the framework of the acoustic approximation. They are also easily programmable and show that angle gather mapping in the case of anisotropic media differs from its isotropic counterpart, with the difference depending mainly on the strength of anisotropy. Synthetic examples demonstrate the importance of including anisotropy in the angle gather generation as mapping of the energy is negatively altered otherwise. In the case of a titled axis of symmetry (TTI), the same VTI formulation is applicable but requires a rotation of the wavenumbers. © 2010 European Association of Geoscientists & Engineers.

  13. Influence of Synthetic Fibers Angle Orientation on Bending Properties of Composite Plywood

    Directory of Open Access Journals (Sweden)

    Mladen Brezović

    2010-12-01

    Full Text Available This paper presents the results of research on carbon fiber angle orientation and quantity of carbon fi bers in yarn on bending properties of plywood. For that purpose the specimens have been defined as multilayer composites made from carbon fibers and veneer. Carbon fibers were inserted in the second and third glue line of the composite with angle variation of 15°. Stresses and strain were analyzed in significant layers together with displacement of the whole composite plate. The influence of carbon fiber angle orientation on properties of the composite (amount of stresses and related strains was significant. The best results have been achieved with carbon fiber angle of 0°, and bidirectional carbon fiber type (BCF with the orientation angle of 90°. The lowest values have been achieved with carbon fiber angle of 65° (unidirectional carbon fibers-UCF, and bidirectional carbon fiber type (BCF with the orientation angle of 45°. Greater quantity of carbon fibers per one yarn has positive influence on decrease of stresses and strains in veneer layers and provides better stiffness of plywood.

  14. Large incidence angle and defocus influence cat's eye retro-reflector

    Science.gov (United States)

    Zhang, Lai-xian; Sun, Hua-yan; Zhao, Yan-zhong; Yang, Ji-guang; Zheng, Yong-hui

    2014-11-01

    Cat's eye lens make the laser beam retro-reflected exactly to the opposite direction of the incidence beam, called cat's eye effect, which makes rapid acquiring, tracking and pointing of free space optical communication possible. Study the influence of cat's eye effect to cat's eye retro-reflector at large incidence angle is useful. This paper analyzed the process of how the incidence angle and focal shit affect effective receiving area, retro-reflected beam divergence angle, central deviation of cat's eye retro-reflector at large incidence angle and cat's eye effect factor using geometrical optics method, and presented the analytic expressions. Finally, numerical simulation was done to prove the correction of the study. The result shows that the efficiency receiving area of cat's eye retro-reflector is mainly affected by incidence angle when the focal shift is positive, and it decreases rapidly when the incidence angle increases; the retro-reflected beam divergence and central deviation is mainly affected by focal shift, and within the effective receiving area, the central deviation is smaller than beam divergence in most time, which means the incidence beam can be received and retro-reflected to the other terminal in most time. The cat's eye effect factor gain is affected by both incidence angle and focal shift.

  15. Experimental investigation of contact angle, curvature, and contact line motion in dropwise condensation and evaporation.

    Science.gov (United States)

    Gokhale, Shripad J; Plawsky, Joel L; Wayner, Peter C

    2003-03-15

    Image-analyzing interferometry is used to measure the apparent contact angle and the curvature of a drop and a meniscus during condensation and evaporation processes in a constrained vapor bubble (CVB) cell. The apparent contact angle is found to be a function of the interfacial mass flux. The interfacial velocity for the drop during condensation and evaporation is a function of the apparent contact angle and the rate of change of radius of curvature. The dependence of velocity on the apparent contact angle is consistent with Tanner's scaling equation. The results support the hypothesis that evaporation/condensation is an important factor in contact line motion. The main purpose of this article is to present the experimental technique and the data. The equilibrium contact angle for the drop is found experimentally to be higher than that for the corner meniscus. The contact angle is a function of the stress field in the fluid. The equilibrium contact angle is related to the thickness of the thin adsorbed film in the microscopic region and depends on the characteristics of the microscopic region. The excess interfacial free energy and temperature jump were used to calculate the equilibrium thickness of the thin adsorbed film in the microscopic region.

  16. Optimum Staging with Varying Thrust Attitude Angle

    Directory of Open Access Journals (Sweden)

    T. N. Srivastava

    1966-07-01

    Full Text Available Optimum staging programme for step rockets of arbitrary number of stages having different specific impulses and mass fractions with stages is derived, the optimization criterion being minimum take-off weight for a desired burntout velocity at an assigned altitude. Variation of thrust attitude angle from stage to stage and effects of gravity factor are taken into account. Analysis is performed for a degenerate problem obtained by relaxing the altitude constraint and it has been shown that problems of Weisbord, Subotowicz, Hall & Zambelli and Malina & Summerfield are the particular cases of the degenerate problem.

  17. Pitch-angle scattering in magnetostatic turbulence. II. Analytical considerations and pitch-angle isotropization

    Science.gov (United States)

    Tautz, R. C.

    2013-10-01

    Aims: The process of pitch-angle isotropization is important for many applications ranging from diffusive shock acceleration to large-scale cosmic-ray transport. Here, the basic analytical description is revisited on the basis of recent simulation results. Methods: Both an analytical and a numerical investigation were undertaken of the Fokker-Planck equation for pitch-angle scattering. Additional test-particle simulations obtained with the help of a Monte-Carlo code were used to verify the conclusions. Results: It is shown that the usual definition of the pitch-angle Fokker-Planck coefficient via the mean-square displacement is flawed. The reason can be traced back to the assumption of homogeneity in time which does not hold for pitch-angle scattering. Conclusions: Calculating the mean free path via the Fokker-Planck coefficient has often proven to give an accurate description. For numerical purposes, accordingly, it is the definition that has to be exchanged in favor of the pitch-angle correlation function.

  18. Pitch-angle scattering in magnetostatic turbulence. II. Analytical considerations and pitch-angle isotropization

    CERN Document Server

    Tautz, R C

    2013-01-01

    Aims. The process of pitch-angle isotropization is important for many applications ranging from diffusive shock acceleration to large-scale cosmic-ray transport. Here, the basic analytical description is revisited on the basis of recent simulation results. Methods. Both an analytical and a numerical investigation were undertaken of the Fokker-Planck equation for pitch-angle scattering. Additional test-particle simulations obtained with the help of a Monte-Carlo code were used to verify the conclusions. Results. It is shown that the usual definition of the pitch-angle Fokker-Planck coefficient via the mean-square displacement is flawed. The reason can be traced back to the assumption of homogeneity in time which does not hold for pitch-angle scattering. Conclusions. Calculating the mean free path via the Fokker-Planck coefficient has often proven to give an accurate description. For numerical purposes, accordingly, it is the definition that has to be exchanged in favor of the pitch-angle correlation function.

  19. Making your presentation fun: creative presentation techniques

    Energy Technology Data Exchange (ETDEWEB)

    KEENEN,MARTHA JANE

    2000-05-18

    What possesses someone to volunteer and go through hoops and red tape to make a presentation at a conference? For that matter, why does anyone ever present anything to anyone? Actually, presentations are a fact of life and there are many reasons for doing a presentation and doing it well. New and existing staff need training and orientation to the way things are done here. Handing all of them a manual and hoping they read it is pretty much a waste of paper. On the other hand, an effective, entertaining and upbeat presentation on the relevant topics is more likely to stick with those people. They will even have a name and face to remember and seek out when they have an issue on or with that topic. This can be a very effective beginning for networking with new peers. The presenter is seen as knowledgeable, as a source of information on company topics and possibly evaluated as a potential mentor or future manager. Project staff and/or peers benefit from clear, concise, presentations of topical knowledge. This is one way that a group working on various aspects of the same project or program can stay in touch and in step with each other. Most importantly, presentations may be the best or only door into the minds (and budgets) of management and customers. These presentations are a wonderful opportunity to address legal and compliance issues, budget, staffing, and services. Here is a chance, maybe the only one, to demonstrate and explain the wonderfulness of a program and the benefit they get by using the services offered most effectively. An interactive presentation on legal and compliance issues can be an effective tool in helping customers and/or management make good risk management decisions.

  20. STUDY ON NECK SHAFT ANGLE AND FEMORAL LENGTH OF SOUTH INDIAN FEMURS

    Directory of Open Access Journals (Sweden)

    Shakil Mohamad Khan

    2014-10-01

    Full Text Available Back ground: Femoral nek anteversion describes the angle subtended by the femoral neck with reference to the transcondylar plane of the distal end of the femur and is usually 15° to 45°. This along with the neck shaft angle, hip axis length, femoral neck width influence the risk of femoral neck fracture. Femoral neck anteversion angle has to be taken into consideration when reduction and fixation is selected as a method of treatment. Objectives: The objectives of present study to find out the measurements of Neck shaft angle, Femoral Length and Neck Length of femur. Materials and Methods: In present study have used 250 femurs from different colleges in south India. The following measurements were conducted Neck shaft angle, Femoral Length and Neck Length of femur. Results: The results of present study are the length of femur was 446.2+26.39mm, right femur was 446.6+26.66mm and left femur was 445.8+26.12mm, the Neck Length femur was 36.3+4.2mm, right femur was 36.1+4.1mm and left femur was 36.4+4.3m. the neck shaft angle of femur was 137.10 , right femur was 137.30 and left femur was 136.90. Conclusion: There is no significance difference between right and left femur measurements. Orthopaedists and Radiologists use the normal range and means of the neck shaft angle in the diagnosis and treatment of the disease of the hip. The angle is increased in congenital subluxation and dislocation of the hip, poliomyelitis, cerebral palsy and idiopathic scoliosis and decreased in the congenital coxavara , post traumatic coxa vara due to malunited femoral neck and inter trochanteric fractures.

  1. a Modified Method for Image Triangulation Using Inclined Angles

    Science.gov (United States)

    Alsadik, Bashar

    2016-06-01

    The ongoing technical improvements in photogrammetry, Geomatics, computer vision (CV), and robotics offer new possibilities for many applications requiring efficient acquisition of three-dimensional data. Image orientation is one of these important techniques in many applications like mapping, precise measurements, 3D modeling and navigation. Image orientation comprises three main techniques of resection, intersection (triangulation) and relative orientation, which are conventionally solved by collinearity equations or by using projection and fundamental matrices. However, different problems still exist in the state - of -the -art of image orientation because of the nonlinearity and the sensitivity to proper initialization and spatial distribution of the points. In this research, a modified method is presented to solve the triangulation problem using inclined angles derived from the measured image coordinates and based on spherical trigonometry rules and vector geometry. The developed procedure shows promising results compared to collinearity approach and to converge to the global minimum even when starting from far approximations. This is based on the strong geometric constraint offered by the inclined angles that are enclosed between the object points and the camera stations. Numerical evaluations with perspective and panoramic images are presented and compared with the conventional solution of collinearity equations. The results show the efficiency of the developed model and the convergence of the solution to global minimum even with improper starting values.

  2. Trajectory reshaping based guidance with impact time and angle constraints

    Institute of Scientific and Technical Information of China (English)

    Zhao Yao; Sheng Yongzhi; Liu Xiangdong

    2016-01-01

    This study presents a novel impact time and angle constrained guidance law for homing missiles. The guidance law is first developed with the prior-assumption of a stationary target, which is followed by the practical extension to a maneuvering target scenario. To derive the closed-form guidance law, the trajectory reshaping technique is utilized and it results in defining a specific poly-nomial function with two unknown coefficients. These coefficients are determined to satisfy the impact time and angle constraints as well as the zero miss distance. Furthermore, the proposed guidance law has three additional guidance gains as design parameters which make it possible to adjust the guided trajectory according to the operational conditions and missile’s capability. Numerical simulations are presented to validate the effectiveness of the proposed guidance law. © 2016 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

  3. Longitudinally slotted conical horn antenna with small flare angle

    Science.gov (United States)

    Scharten, T.; Nellen, J.; van den Bogaart, F.

    1981-06-01

    The radiation and cross polarization characteristics of a longitudinally slotted, conical horn antenna with small flare angle, excited in the modified TE(11) mode, are investigated. To this end the electromagnetic wave propagation in a longitudinally slotted circular waveguide is studied first, using a wall reactance model. Because of the need to introduce mode-dependent wall reactances in the present structure, conditions for orthogonality are given. Propagation characteristics and field line patterns are presented. It turns out that the modified TE(11) mode in this guide, used as an aperture antenna, produces a main radiation lobe which can be made nearly symmetrical around the axis over a wide frequency range by a proper choice of the slot depth. As a typical example, the maximum cross polarization level in the main lobe is lower than -30 to -45 dB, dependent on slot depth and frequency range. Experiments carried out with a slotted conical horn antenna with small flare angle confirm the theoretical results.

  4. Joint angle estimation with accelerometers for dynamic postural analysis.

    Science.gov (United States)

    Ma, Jianting; Kharboutly, Haissam; Benali, Abderraouf; Benamar, Faïz; Bouzit, Mourad

    2015-10-15

    This paper presents a new accelerometer based method for estimating the posture of a subject standing on a dynamic perturbation platform. The induced perturbation is used to study the control mechanisms as well as the balance requirements that regulate the upright standing. These perturbations are translated into different intensity levels of speed and acceleration along longitudinal and lateral directions of motion. In our method, the human posture is modeled by a tridimensional, three-segment inverted pendulum which simultaneously takes into account both the anterior-posterior and medio-lateral strategies of hip and ankle. Four tri-axial accelerometers are used her, one accelerometer is placed on the platform, and the other three are attached to a human subject. Based on the results, the joint angle estimated compare closely to measurements from magnetic encoders placed on an articulated arm joint. The results were also comparable to those found when using a high-end optical motion capture system coupled with advanced biomechanical simulation software. This paper presents the comparisons of our accelerometer-based method with encoder and optical marker based method of the estimated joint angles under different dynamics perturbations. PMID:26338097

  5. Embedability between right-angled Artin groups

    CERN Document Server

    Kim, Sang-hyun

    2011-01-01

    In this article we study the right-angled Artin subgroups of a given right-angled Artin group. Starting with a graph $\\gam$, we produce a new graph through a purely combinatorial procedure, and call it the extension graph $\\gam^e$ of $\\gam$. We produce a second graph $\\gam^e_k$, the clique graph of $\\gam^e$, by adding extra vertices for each complete subgraph of $\\gam^e$. We prove that each finite induced subgraph $\\Lambda$ of $\\gam^e$ gives rise to an inclusion $A(\\Lambda)\\to A(\\gam)$. Conversely, we show that if there is an inclusion $A(\\Lambda)\\to A(\\gam)$ then $\\Lambda$ is an induced subgraph of $\\gam^e_k$. These results have a number of corollaries. Let $P_4$ denote the path on four vertices and let $C_n$ denote a cycle of length $n$. We prove that $A(P_4)$ embeds in $A(\\gam)$ if and only if $P_4$ is an induced subgraph of $\\gam$. We prove that if $F$ is any finite forest then $A(F)$ embeds in $A(P_4)$. We recover the first author's result on co--contraction of graphs and prove that if $\\gam$ has no tria...

  6. Cluster headache or narrow angle glaucoma?

    Directory of Open Access Journals (Sweden)

    Prasad Palimar

    1991-01-01

    Full Text Available A 47 year old man with episodes of attacks of pain, redness and mild blurring of vision was investigated for narrow angle glaucoma in view of shallow anterior chambers and a cupped optic disc. The history was reviewed following a spontaneous attack in hospital, which had features other than acute glaucoma. A diagnosis of cluster headache was made on the basis of tests. Cluster headache has been defined as unilateral intense pain, involving the eye and head on one side, usually associated with flushing, nasal congestion and lacrimation; the attacks recurring one or more times daily and lasting 20 - 120 minutes. Such attacks commonly continue for weeks or months and are separated by an asymptomatic period of months to years. This episodic nature, together with unilaterality and tendency to occur at night, closely mimics narrow angle glaucoma. Further, if patients have shallow anterior chambers and disc cupping, the differentiation becomes more difficult yet critical. Resource to provocative tests is often the only answer as the following case report demonstrates.

  7. Vertical Crossing Angle in IR8

    CERN Document Server

    Holzer , B J; Alemany, R

    2013-01-01

    The operation of the LHCb spectrometer dipole has a considerably larger and more challenging impact on the geometry of the LHC beams than the magnets in the high luminosity regions [1]. The integrated dipole field of 4 Tm deflects the beams in the horizontal plane, and using a set of three dipole magnets, called "compensators" a closed horizontal orbit bump is created. This paper summarizes the basic layout of the beam geometry in IR8 under the influence of the LHCb dipole and its compensators and shows the theoretically expected beam orbits, envelopes and aperture needs in the originally designed version. LHCb operation with both field polarities leads to unequal net crossing angles between the two beams and affects the experiment acceptance. It had been proposed therefore to establish a LHC operation mode where the originally designed horizontal crossing angle is shifted at high energy into the vertical plane leading to a vertical crossing scheme at luminosity operation. The new scheme has been successfully...

  8. Contact angles of liquid metals on quasicrystals

    International Nuclear Information System (INIS)

    Wetting with μm-sized Pb droplets on thin polycrystalline films of decagonal Al13Co4 is reported. The films were prepared under high vacuum conditions in order to have Pb droplets lying on a clean surface. The method used is sequential deposition and annealing of specific stackings of Al and Co layers of nanometric thicknesses. A 300 nm thick Pb slab was then deposited on top of the films and dewetting experiments were followed in situ in a scanning Auger microprobe. The contact angle between the Pb droplet and the surface of the film is measured to be 49 deg. ± 7 deg. Further investigation performed by cross section transmission electron microscopy allows us to better characterize the interface. Taking into account the rugosity of the film, it is concluded that there is partial wetting of the film, which corresponds to a smaller contact angle. The comparison with other results obtained either with pure metals or with a cubic AlCo compound leads to the conclusion that the wetting behaviour of Pb on the surface of a decagonal compound is close to that of a metal with a high melting point and not significantly different from that of a crystalline compound with a small unit cell

  9. A field study of coherent flow structures over low angle dunes: Fraser Estuary, British Columbia

    Science.gov (United States)

    Bradley, R. W.; Hendershot, M. L.; Venditti, J. G.; Kostaschuk, R. A.; Allison, M. A.; Church, M. A.

    2011-12-01

    Aqueous dunes are present in nearly all sand bedded alluvial channels and can significantly influence flow resistance and sediment transport and deposition. The geometry of these bedforms can take on a high angle asymmetrical or low angle symmetrical shape. While advances have been made in understanding the mean and turbulent flow over high angle dunes, far less progress has been made in detailing flow over low angle dunes, commonly observed in large rivers, due to difficulties measuring near the bed and quantifying the turbulence over these bedforms. This field study documents the flow over low angle dunes in the Fraser Estuary, British Columbia, using an acoustic Doppler profiler (aDcp) to measure 3-D flow characteristics and a multi-beam echo sounder (MBES) to provide high-resolution bed topography. Measurements were made over a dune field (~1 km long and ~0.5 wide) through two semi-diurnal tidal cycles during the 2010 freshet. We examine the coupling between the bedform morphology and the generation of coherent flow structures. Bedforms in the dune field range from low-angle symmetric to higher angle asymmetric and vary over tidal cycles; however, none display the classic angle of repose geometry. Mean flow velocity increases on falling tide while it decreases the rising tide. At lower tides, large scale motions caused by topographic forcing emerge on stoss slopes and rise up over the crest producing variations in suspended sediment over the bedforms. Our analysis is intended to contribute insight into what controls the occurrence of low angle bedforms in rivers.

  10. Lateral angle: a method for sexing using the petrous bone

    DEFF Research Database (Denmark)

    Norén, Anna; Lynnerup, Niels; Czarnetzki, Alfred;

    2005-01-01

    very fragmented skeletal remains or cremated bones, where the petrous bone may still be readily recognizable. The method was tested using a forensic sample of 113 petrous bones with known sex. Intra- and interobserver testing was also performed. We found a statistically significant difference in angle......We report on the results of applying the so-called lateral angle method for sex determination on skeletal remains. The lateral angle denotes the angle of the internal auditory canal in relation to the medial surface of the petrous part of the temporal bone. The method involves making a small cast...... size between males and females (mean angle size of males, 39.3 degrees ; mean angle size of females, 48.2 degrees ; P < 0.001). There was no bilateral difference in angle size. In blind trials, 83.2% of petrous bones were assigned to the correct sex. We also tested the lateral angle method against an...

  11. Alternative IR geometries for TESLA with a small crossing angle

    OpenAIRE

    Appleby, R.; Angal-Kalinin, D; Bambade, P.; Mouton, B.; Napoly, O.; Payet, J.; Collaboration, the TESLA

    2004-01-01

    The formulation of hybrid crossing angle schemes has been a recent development of the TESLA collision geometry debate. Here we report on two such schemes, characterised by either a small vertical or horizontal beam crossing angle.

  12. Small-angle approximation to the transfer of narrow laser beams in anisotropic scattering media

    Science.gov (United States)

    Box, M. A.; Deepak, A.

    1981-01-01

    The broadening and the signal power detected of a laser beam traversing an anisotropic scattering medium were examined using the small-angle approximation to the radiative transfer equation in which photons suffering large-angle deflections are neglected. To obtain tractable answers, simple Gaussian and non-Gaussian functions for the scattering phase functions are assumed. Two other approximate approaches employed in the field to further simplify the small-angle approximation solutions are described, and the results obtained by one of them are compared with those obtained using small-angle approximation. An exact method for obtaining the contribution of each higher order scattering to the radiance field is examined but no results are presented.

  13. Measurements of sunspot group tilt angles for solar cycles 19-24

    Science.gov (United States)

    Isik, Seda; Isik, Emre

    2016-07-01

    The tilt angle of a sunspot group is a critical quantity in the surface transport magnetic flux on global scales, playing a role in the solar dynamo. To investigate Joy's law for four cycles, we measured the tilt angles of sunspot groups for solar cycles 19-24. We have developed an IDL routine, which allows the user to interactively select and measure sunspot positions and areas on the solar disc, using the sunspot drawing database of Kandilli Observatory. The method is similar to that used by others in the literature, with the exception that sunspot groups were identified manually, which has improved the accuracy of the tilt angles. We present cycle averages of the tilt angle and compare the results with the existing data in the literature.

  14. An Optimal Angle of Launching a Point Mass in a Medium with Quadratic Drag Force

    CERN Document Server

    Chudinov, P

    2005-01-01

    A classic problem of the motion of a point mass (projectile) thrown at an angle to the horizon is reviewed. The air drag force is taken into account with the drag factor assumed to be constant. Analytic approach is used for investigation. The problem of finding an optimal angle of launching a point mass in a medium with quadratic drag force is considered. An equation for determining a value of this angle is obtained. After finding the optimal angle of launching, eight main parameters of the point mass motion are analytically determined. These parameters are used to construct analytically six main functional relationships of the problem. Simple analytic formulas are used to solve two problems of optimization aimed to maximize the flight range of a point mass and minimize the initial speed of the point mass for getting to the given point on the plane. The motion of a baseball is presented as an example.

  15. Influence of blade angle distribution along leading edge on cavitation performance of a centrifugal pump

    Science.gov (United States)

    Xu, Y.; Tan, L.; Cao, S. L.; Wang, Y. C.; Meng, G.; Qu, W. S.

    2015-01-01

    The influence of blade angle distribution along leading edge on cavitation performance of centrifugal pumps is analysed in the present paper. Three sets of blade angle distribution along leading edge for three blade inlet angles are chosen to design nine centrifugal pump impellers. The RNG k-epsilon turbulence model and the Zwart-Gerber-Belamri cavitation model are employed to simulate the cavitation flows in centrifugal pumps with different impellers and the same volute. The numerical results are compared with the experimental data, and the comparison proves that the numerical simulation can accurately predict the cavitation performance of centrifugal pumps. On the basis of the numerical simulations, the pump head variations with pump inlet pressure, and the flow details in centrifugal pump are revealed to demonstrate the influence of blade angle distribution along leading edge on cavitation performances of centrifugal pumps.

  16. Elevation estimation for low-angle target based on reflection paths suppression

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In the signal processing for metrewave radar,the reflection paths of target echoes can cause severe error in the elevation estimation for the low-angle target tracking.The exact angles of the reflection paths are unknown beforehand,and therefore,the reflection paths can not be suppressed easily.Therefore,in this article,an improved reflection paths suppression approach is presented.A block matrix aggregate is constructed based on the possible angles of the reflection paths.Combined with the beamforming-like processing,a generalized maximum likelihood estimation is derived to optimize the estimation.Moreover,the noise reduction method based on the Toeplitz covariance matrix is used for better performance.This approach is applied to the real data collected by the low-angle tracking radar with 8-channel vertical array.The experiment results show that the reflection effects are reduced and the accuracy of the elevation estimate is improved.

  17. An advective diffusion process on hot wasted water discharged to a depression angle direction into water

    International Nuclear Information System (INIS)

    Effect of change in wasted water from nuclear or fossil fuel power plants discharging direction from horizontal one to depression angle one on an advective diffusion process of hot wasted water was investigated. As a result, it could be confirmed that an effect of depression angle jet discharge on water temperature reduction and so forth could be applied present experimental equation on horizontal discharging by a coordinate transformation of various factors with discharging water angle. And, a judgement equation to obtain a limiting area of hot wasted water affecting with bed surface was obtained by using distance from the lowest point of jet to the sea bed, inner diameter of discharging pipe, and field number for parameters, to elucidate its effectiveness. Furthermore, a diagram to estimate an effect of depression angle discharging water in the area on water temperature reduction and so forth was also proposed. (G.K.)

  18. Hybrid algorithm for rotor angle security assessment in power systems

    OpenAIRE

    D. Prasad Wadduwage; Udaya D. Annakkage; Christine Qiong Wu

    2015-01-01

    Transient rotor angle stability assessment and oscillatory rotor angle stability assessment subsequent to a contingency are integral components of dynamic security assessment (DSA) in power systems. This study proposes a hybrid algorithm to determine whether the post-fault power system is secure due to both transient rotor angle stability and oscillatory rotor angle stability subsequent to a set of known contingencies. The hybrid algorithm first uses a new security measure developed based on ...

  19. Meningioma of the Posterior Skull Base

    Science.gov (United States)

    Biggs, Michael Thomas; Fagan, Paul A.; Sheehy, John P.R.; Bentivoglio, Peter J.; Doust, Bruce D.; Tonkin, John

    1991-01-01

    Combined intratemporal and cerebellopontine angle meningiomas are rejatively rare. There are unsolved problems with the stability of the skull and spine and the lower cranial nerves and there is a marked tendency for the tumor to involve the spinal cord. This article reports on five cases of combined intratemporal and cerebellopontine angle meningiomas. ImagesFigure 1p44-bFigure 2Figure 3Figure 4Figure 5 PMID:17170820

  20. Surgery for an "Acute Erection Angle," When Counseling Fails

    NARCIS (Netherlands)

    Nugteren, Helena M.; Pascal, Astrid L.; Schultz, Willibrord C. M. Weijmar; van Driel, Mels F.

    2010-01-01

    Introduction. During erection, the penis increases in volume, rigidity, and angle. Textbooks of urology and sexology provide only very limited information about erection angle dysfunction. In some men, this angle is too tight toward their belly, causing problems with intercourse. Aim. We reported tw

  1. Optimal Angle Reduction - A Behavioral Approach to Linear System Approximation

    NARCIS (Netherlands)

    Roorda, B.; Weiland, S.

    2000-01-01

    We investigate the problem of optimal state reduction under minimization of the angle between system behaviors. The angle is defined in a worst-case sense, as the largest angle that can occur between a system trajectory and its optimal approximation in the reduced order model. This problem is analys

  2. Angle Class II malocclusion treated with extraction of permanent teeth

    Directory of Open Access Journals (Sweden)

    Gustavo Mattos Barreto

    2013-08-01

    Full Text Available Angle Class II malocclusion associated with anterior open bite in adult patients demands a carefully elaborated orthodontic planning, aiming at restoring not only harmonious dental and facial esthetics, but also a balanced masticatory function. Orthognathic surgery or permanent teeth extraction are often the choice of treatment, therefore, treatment decision is related to all dental, skeletal and functional aspects. The present report discusses orthodontic compensation carried out by means of upper premolar extraction performed to correct the Class II canine relationship and, consequently, the anterior open bite, accepting that the upper incisors be retroclined. This clinical case was presented to the Brazilian Board of Orthodontics and Dentofacial Orthopedics (BBO as part of the requirements for obtaining the BBO Certification.

  3. Dealing with uncertainties in angles-only initial orbit determination

    Science.gov (United States)

    Armellin, Roberto; Di Lizia, Pierluigi; Zanetti, Renato

    2016-08-01

    A method to deal with uncertainties in initial orbit determination (IOD) is presented. This is based on the use of Taylor differential algebra (DA) to nonlinearly map uncertainties from the observation space to the state space. When a minimum set of observations is available, DA is used to expand the solution of the IOD problem in Taylor series with respect to measurement errors. When more observations are available, high order inversion tools are exploited to obtain full state pseudo-observations at a common epoch. The mean and covariance of these pseudo-observations are nonlinearly computed by evaluating the expectation of high order Taylor polynomials. Finally, a linear scheme is employed to update the current knowledge of the orbit. Angles-only observations are considered and simplified Keplerian dynamics adopted to ease the explanation. Three test cases of orbit determination of artificial satellites in different orbital regimes are presented to discuss the feature and performances of the proposed methodology.

  4. Superwide-angle acoustic propagations above the critical angles of the Snell law in liquid—solid superlattice

    Science.gov (United States)

    Zhang, Sai; Zhang, Yu; Gao, Xiao-Wei

    2014-12-01

    In this paper, superwide-angle acoustic propagations above the critical angles of the Snell law in liquid—solid superlattice are investigated. Incident waves above the critical angles of the Snell law usually inevitably induce total reflection. However, incident waves with big oblique angles through the liquid—solid superlattice will produce a superwide angle transmission in a certain frequency range so that total reflection does not occur. Together with the simulation by finite element analysis, theoretical analysis by using transfer matrix method suggests the Bragg scattering of the Lamb waves as the physical mechanism of acoustic wave super-propagation far beyond the critical angle. Incident angle, filling fraction, and material thickness have significant influences on propagation. Superwide-angle propagation phenomenon may have potential applications in nondestructive evaluation of layered structures and controlling of energy flux.

  5. Computer simulation of dislocation core structure of metastable left angle 111 right angle dislocations in NiAl

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Z.Y. (Dept. of Materials Science and Engineering, Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States)); Vailhe, C. (Dept. of Materials Science and Engineering, Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States)); Farkas, D. (Dept. of Materials Science and Engineering, Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States))

    1993-10-01

    The atomistic structure of dislocation cores of left angle 111 right angle dislocations in NiAl was simulated using embedded atom method potentials and molecular statics computer simulation. In agreement with previous simulation work and experimental observations, the complete left angle 111 right angle dislocation is stable with respect to the two superpartials of 1/2 left angle 111 right angle separated by an antiphase boundary. The structure of the latter configuration, though metastable, is of interest in the search for ways of improving ductility in this material. The structure of the complete dislocation and that of the metastable superpartials was studied using atomistic computer simulation. An improved visualization method was used for the representation of the resulting structures. The structure of the partials is different from that typical of 1/2 left angle 111 right angle dislocations in b.c.c. materials and that reported previously for the B2 structure using model pair potentials. (orig.)

  6. Presentation of a new BRDF measurement device

    Science.gov (United States)

    Serrot, Gerard; Bodilis, Madeleine; Briottet, Xavier; Cosnefroy, Helene

    1998-12-01

    The bi-directional reflectance distribution function (BRDF) plays a major role to evaluate or analyze signals reflected by Earth in the solar spectrum. A BRDF measurement device that covers a large spectral and directional domain was recently developed by ONERA/DOTA. It was designed to allow both laboratory and outside measurements. Its main characteristics are a spectral domain: 0.42-0.95 micrometers ; a geometrical domain: 0-60 degrees for zenith angle, 0-180 degrees for azimuth; a maximum target size for nadir measurements: 22 cm. For a given zenith angle of the source, the BRDF device needs about seven minutes to take measurements for a viewing zenith angle varying from 0-60 degrees and relative azimuth angle varying from 0-180 degrees. The performances, imperfections and properties of each component of the measurement chain are studied. A part of the work was devoted to characterize precisely the source, and particularly the spatial variability of the irradiance at the target level, the temporal stability and the spectral profile of the lamp. Some of these imperfections are modeled and taken into account in corrections of BRDF measurements. Concerning the sensor, a calibration in wavelength was done. Measurements of bi- directional reflectance of which is well known. A software was developed to convert all the raw data acquired automatically into BRDF values. To illustrate measurements taken by this device, some results are also presented here. They are taken over sand and short grass, for different wavelengths and geometrical conditions.

  7. Angle-resolved photoemission extended fine structure

    International Nuclear Information System (INIS)

    Measurements of the Angle-Resolved Photoemission Extended Fine Structure (ARPEFS) from the S(1s) core level of a c(2 x 2)S/Ni(001) are analyzed to determine the spacing between the S overlayer and the first and second Ni layers. ARPEFS is a type of photoelectron diffraction measurement in which the photoelectron kinetic energy is swept typically from 100 to 600 eV. By using this wide range of intermediate energies we add high precision and theoretical simplification to the advantages of the photoelectron diffraction technique for determining surface structures. We report developments in the theory of photoelectron scattering in the intermediate energy range, measurement of the experimental photoemission spectra, their reduction to ARPEFS, and the surface structure determination from the ARPEFS by combined Fourier and multiple-scattering analyses. 202 refs., 67 figs., 2 tabs

  8. Narrow-angle astrometry with PRIMA

    CERN Document Server

    Sahlmann, J; Mérand, A; Zimmerman, N; Abuter, R; Chazelas, B; Delplancke, F; Henning, T; Kaminski, A; Köhler, R; Launhardt, R; Mohler, M; Pepe, F; Queloz, D; Quirrenbach, A; Reffert, S; Schmid, C; Schuhler, N; Schulze-Hartung, T

    2012-01-01

    The Extrasolar Planet Search with PRIMA project (ESPRI) aims at characterising and detecting extrasolar planets by measuring the host star's reflex motion using the narrow-angle astrometry capability of the PRIMA facility at the Very Large Telescope Interferometer. A first functional demonstration of the astrometric mode was achieved in early 2011. This marked the start of the astrometric commissioning phase with the purpose of characterising the instrument's performance, which ultimately has to be sufficient for exoplanet detection. We show results obtained from the observation of bright visual binary stars, which serve as test objects to determine the instrument's astrometric precision, its accuracy, and the plate scale. Finally, we report on the current status of the ESPRI project, in view of starting its scientific programme.

  9. Flow angle from intermediate mass fragment measurements

    Energy Technology Data Exchange (ETDEWEB)

    Rami, F.; Crochet, P.; Dona, R.; De Schauenburg, B.; Wagner, P.; Alard, J.P.; Andronic, A.; Basrak, Z.; Bastid, N.; Belyaev, I.; Bendarag, A.; Berek, G.; Best, D.; Caplar, R.; Devismes, A.; Dupieux, P.; Dzelalija, M.; Eskef, M.; Fodor, Z.; Gobbi, A.; Grishkin, Y.; Herrmann, N.; Hildenbrand, K.D.; Hong, B.; Kecskemeti, J.; Kirejczyk, M.; Korolija, M.; Kotte, R.; Lebedev, A.; Leifels, Y.; Merlitz, H.; Mohren, S.; Moisa, D.; Neubert, W.; Pelte, D.; Petrovici, M.; Pinkenburg, C.; Plettner, C.; Reisdorf, W.; Schuell, D.; Seres, Z.; Sikora, B.; Simion, V.; Siwek-Wilczynska, K.; Stoicea, G.; Stockmeir, M.; Vasiliev, M.; Wisniewski, K.; Wohlfarth, D.; Yushmanov, I.; Zhilin, A

    1999-02-15

    Directed sideward flow of light charged particles and intermediate mass fragments was measured in different symmetric reactions at bombarding energies from 90 to 800 A MeV. The flow parameter is found to increase with the charge of the detected fragment up to Z = 3-4 and then turns into saturation for heavier fragments. Guided by simple simulations of an anisotropic expanding thermal source, we show that the value at saturation can provide a good estimate of the flow angle, {theta}{sub flow}, in the participant region. It is found that {theta}{sub flow} depends strongly on the impact parameter. The excitation function of {theta}{sub flow} reveals striking deviations from the ideal hydrodynamical scaling. The data exhibit a steep rise of {theta}{sub flow} to a maximum at around 250 - 400 A MeV, followed by a moderate decrease as the bombarding energy increases further.

  10. On large angle multiple gluon radiation

    CERN Document Server

    Dokshitzer, Y L; Dokshitzer, Yu.L.

    2003-01-01

    Jet shape observables which involve measurements restricted to a part of phase space are sensitive to multiplication of soft gluon with large relative angles and give rise to specific single logarithmically enhanced (SL) terms (non-global logs). We consider associated distributions in two variables which combine measurement of a jet shape V in the whole phase space (global) and that of the transverse energy flow away from the jet direction, Eout (non-global). We show that associated distributions factorize into the global distribution in V and a factor that takes into account SL contributions from multi-gluon ``hedgehog'' configurations in all orders. The latter is the same that describes the single-variable Eout distribution, but evaluated at a rescaled energy VQ.

  11. Angle-resolved cathodoluminescence imaging polarimetry

    CERN Document Server

    Osorio, Clara I; Brenny, Benjamin; Polman, Albert; Koenderink, A Femius

    2015-01-01

    Cathodoluminescence spectroscopy (CL) allows characterizing light emission in bulk and nanostructured materials and is a key tool in fields ranging from materials science to nanophotonics. Previously, CL measurements focused on the spectral content and angular distribution of emission, while the polarization was not fully determined. Here we demonstrate a technique to access the full polarization state of the cathodoluminescence emission, that is the Stokes parameters as a function of the emission angle. Using this technique, we measure the emission of metallic bullseye nanostructures and show that the handedness of the structure as well as nanoscale changes in excitation position induce large changes in polarization ellipticity and helicity. Furthermore, by exploiting the ability of polarimetry to distinguish polarized from unpolarized light, we quantify the contributions of different types of coherent and incoherent radiation to the emission of a gold surface, silicon and gallium arsenide bulk semiconductor...

  12. Magic-angle spinning NMR of cold samples.

    Science.gov (United States)

    Concistrè, Maria; Johannessen, Ole G; Carignani, Elisa; Geppi, Marco; Levitt, Malcolm H

    2013-09-17

    Magic-angle-spinning solid-state NMR provides site-resolved structural and chemical information about molecules that complements many other physical techniques. Recent technical advances have made it possible to perform magic-angle-spinning NMR experiments at low temperatures, allowing researchers to trap reaction intermediates and to perform site-resolved studies of low-temperature physical phenomena such as quantum rotations, quantum tunneling, ortho-para conversion between spin isomers, and superconductivity. In examining biological molecules, the improved sensitivity provided by cryogenic NMR facilitates the study of protein assembly or membrane proteins. The combination of low-temperatures with dynamic nuclear polarization has the potential to boost sensitivity even further. Many research groups, including ours, have addressed the technical challenges and developed hardware for magic-angle-spinning of samples cooled down to a few tens of degrees Kelvin. In this Account, we briefly describe these hardware developments and review several recent activities of our group which involve low-temperature magic-angle-spinning NMR. Low-temperature operation allows us to trap intermediates that cannot be studied under ambient conditions by NMR because of their short lifetime. We have used low-temperature NMR to study the electronic structure of bathorhodopsin, the primary photoproduct of the light-sensitive membrane protein, rhodopsin. This project used a custom-built NMR probe that allows low-temperature NMR in the presence of illumination (the image shows the illuminated spinner module). We have also used this technique to study the behavior of molecules within a restricted environment. Small-molecule endofullerenes are interesting molecular systems in which molecular rotors are confined to a well-insulated, well-defined, and highly symmetric environment. We discuss how cryogenic solid state NMR can give information on the dynamics of ortho-water confined in a fullerene

  13. Size as a Risk Factor for Growth in Conservatively Managed Vestibular Schwannomas: The Birmingham Experience.

    Science.gov (United States)

    Daultrey, Charles R J; Rainsbury, James W; Irving, Richard M

    2016-10-01

    This article discusses conservatively managed tumors, whether larger tumors at presentation are more likely to grow, and whether position at presentation corresponds with growth. A review is presented of more than 900 patients managed at Queen Elizabeth Hospital, Birmingham, between 1997 and 2012. Tumors were arbitrarily divided into 3 groups: intracanalicular (IC), and extracanalicular (EC) tumors measuring 1 to 10 mm or 11 to 20 mm at the cerebellopontine angle. This series shows that larger EC tumors grow faster than IC tumors and that EC tumors overall at presentation are more likely to grow than IC tumors. PMID:27565393

  14. A Multifunctional Joint Angle Sensor with Measurement Adaptability

    Directory of Open Access Journals (Sweden)

    Wei Quan

    2013-11-01

    Full Text Available The paper presents a multifunctional joint sensor with measurement adaptability for biological engineering applications, such as gait analysis, gesture recognition, etc. The adaptability is embodied in both static and dynamic environment measurements, both of body pose and in motion capture. Its multifunctional capabilities lay in its ability of simultaneous measurement of multiple degrees of freedom (MDOF with a single sensor to reduce system complexity. The basic working mode enables 2DOF spatial angle measurement over big ranges and stands out for its applications on different joints of different individuals without recalibration. The optional advanced working mode enables an additional DOF measurement for various applications. By employing corrugated tube as the main body, the sensor is also characterized as flexible and wearable with less restraints. MDOF variations are converted to linear displacements of the sensing elements. The simple reconstruction algorithm and small outputs volume are capable of providing real-time angles and long-term monitoring. The performance assessment of the built prototype is promising enough to indicate the feasibility of the sensor.

  15. Penetrating head injury from angle grinder: A cautionary tale

    Directory of Open Access Journals (Sweden)

    S Senthilkumaran

    2010-01-01

    Full Text Available Penetrating cranial injury is a potentially life-threatening condition. Injuries resulting from the use of angle grinders are numerous and cause high-velocity penetrating cranial injuries. We present a series of two penetrating head injuries associated with improper use of angle grinder, which resulted in shattering of disc into high velocity missiles with reference to management and prevention. One of those hit on the forehead of the operator and the other on the occipital region of the co-worker at a distance of five meters. The pathophysiological consequence of penetrating head injuries depends on the kinetic energy and trajectory of the object. In the nearby healthcare center the impacted broken disc was removed without realising the consequences and the wound was packed. As the conscious level declined in both, they were referred. CT brain revealed fracture in skull and changes in the brain in both. Expeditious removal of the penetrating foreign body and focal debridement of the scalp, skull, dura, and involved parenchyma and Watertight dural closure were carried out. The most important thing is not to remove the impacted foreign body at the site of accident. Craniectomy around the foreign body, debridement and removal of foreign body without zigzag motion are needed. Removal should be done following original direction of projectile injury. The neurological sequelae following the non missile penetrating head injuries are determined by the severity and location of initial injury as well as the rapidity of the exploration and fastidious debridement.

  16. Temperature Influence on Divergence Angles of Quartz Crystal Wollaston Prism

    International Nuclear Information System (INIS)

    We propose a structural angle and main refractive indices as two key factors to understand the temperature influence on the divergence angles of the Wollaston prism. The temperature influence on the divergence angles of quartz crystal Wollaston prism is studied theoretically The results show that divergence angles decrease with increasing temperature, while the divergence angle of e-light decrease more quickly than that of o-light. The testing system is established to verify the above results, and the experimental results are in agreement well with the theoretical analysis. (fundamental areas of phenomenology (including applications))

  17. Small angle X-ray scattering study of calreticulin reveals conformational plasticity

    DEFF Research Database (Denmark)

    Toft, Katrine Nørgaard; Larsen, Nanna; Jørgensen, Flemming Steen;

    2008-01-01

    Calreticulin plays a central role in vital cell processes such as protein folding, Ca(2+) homeostasis and immunogenicity. Even so, only limited three-dimensional structural information is presently available. We present a series of Small-Angle X-ray Scattering data on human placenta calreticulin...... the functional consequences of the conformational plasticity of the calreticulin P-domain....

  18. Síncope cardíaca reflexa por "nevralgia" do glossofaríngeo: rara apresentação dessa doença Cardiac syncope induced by glossopharyngeal "neuralgia": a rare presentation

    Directory of Open Access Journals (Sweden)

    Helio Korkes

    2006-11-01

    Full Text Available A primeira descrição de dor severa no trajeto do nervo glossofaríngeo foi realizada por Weisenberg, em 1910¹, em um paciente com tumor do ângulo ponto cerebelar. Entretanto, coube a Harris, em 1926², nomear como nevralgia do nervo glossofaríngeo esse raro quadro clínico, caracterizado por paroxismos de dor intensa, unilaterais, na região posterior da língua, no palato mole, na garganta e na região lateral e posterior da faringe, irradiando para o ouvido. A dor pode ser desencadeada por deglutição, tosse, bocejo ou mastigação e normalmente dura de segundos a minutos. A associaç��o de nevralgia do glossofaríngeo e síncope é muito rara e se deve a breves períodos de bradicardia, assistolia ou hipotensão, sendo a primeira descrição dessa associação, com essa fisiopatologia, realizada por Riley e cols., em 1942³.The first description of severe pain in the distribution of the glossopharyngeal nerve is credited to Weisenberg, in 1910¹, in a patient with cerebellopontine angle tumor. However, it was Harris, in 1926², who coined the term glossopharyngeal neuralgia to describe this rare condition characterized by paroxysms of excruciating pain located laterally at the back of the tongue, soft palate, throat, and lateral and posterior pharynx, radiating to the ear. Swallowing, coughing, yawning or chewing may trigger pain, which usually lasts from seconds to minutes. The association between glossopharyngeal neuralgia and syncope is very rare, being identified by brief episodes of bradycardia, asystole, and hypotension. Such an association, with this same pathophysiology, was first described by Riley et al³ in 1942.

  19. Impacts of tropical cyclone inflow angle on ocean surface waves

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wei; HONG Xin

    2011-01-01

    The inflow angle of tropical cyclones (TC) is generally neglected in numerical studies of ocean surface waves induced by TC. In this study, the impacts of TC inflow angle on ocean surface waves were investigated using a high-resolution wave model. Six numerical experiments were conducted to examine, in detail, the effects of inflow angle on mean wave parameters and the spectrum of wave directions. A comparison of the waves simulated in these experiments shows that inflow angle significantly modifies TC-induced ocean surface waves. As the inflow angle increases, the asymmetric axis of the significant wave height (SWH) field shifts 30° clockwise, and the maximum SWH moves from the front-right to the rear-right quadrant. Inflow angle also affects other mean wave parameters, especially in the rear-left quadrant, such as the mean wave direction, the mean wavelength, and the peak direction. Inflow angle is a key factor in wave models for the reproduction of double-peak or multi-peak patterns in the spectrum of wave directions. Sensitivity experiments also show that the simulation with a 40° inflow angle is the closest to that of the NOAA statistical SLOSH inflow angle. This suggests that 40° can be used as the inflow angle in future TC-induced ocean surface wave simulations when SLOSH or observed inflow angles are not available.

  20. Angle Kappa and its importance in refractive surgery

    Directory of Open Access Journals (Sweden)

    Majid Moshirfar

    2013-01-01

    Full Text Available Angle kappa is the difference between the pupillary and visual axis. This measurement is of paramount consideration in refractive surgery, as proper centration is required for optimal results. Angle kappa may contribute to MFIOL decentration and its resultant photic phenomena. Adjusting placement of MFIOLs for angle kappa is not supported by the literature but is likely to help reduce glare and haloes. Centering LASIK in angle kappa patients over the corneal light reflex is safe, efficacious, and recommended. Centering in-between the corneal reflex and the entrance pupil is also safe and efficacious. The literature regarding PRK in patients with an angle kappa is sparse but centering on the corneal reflex is assumed to be similar to centering LASIK on the corneal reflex. Thus, centration of MFIOLs, LASIK, and PRK should be focused on the corneal reflex for patients with a large angle kappa. More research is needed to guide surgeons′ approach to angle kappa.

  1. Teaching Presentation Skills

    Science.gov (United States)

    Baker, William H.; Thompson, Michael P.

    2004-01-01

    Effective teaching of presentation skills focuses on the most important element of the presentation--the message itself. Some instructors place the heaviest emphasis on the messenger (the presenter) and focus their presentation feedback on all the presenter is doing wrong--saying "um," gesturing awkwardly, and so forth. When students receive this…

  2. Relationship Between Differential Interference Angle and Parameter of Experiment in Molecular Beam

    Institute of Scientific and Technical Information of China (English)

    LI Yong-Qing; LI Jian; MA Feng-Cai

    2006-01-01

    Collisional quantum interference (CQI) was observed in the intramolecular rotational energy transfer in the experiment of the static cell, and the integral interference angles were measured. To observe more precise information, the experiment in the molecular beam should be taken, from which the relationship between the differential interference angle and the scattering angle can be obtained. In this paper, the theoretical model of CQI is described in an atom-diatom system in the condition of the molecular beam, based on the first-Born approximation of time-dependent perturbation theory, taking into accounts the long-range interaction potential. The method of observing and measuring correctly the differential interference angle is presented. The changing tendency of the differential interference angle with the impact parameter and relative velocity is discussed. The changing tendencies of the differential interference angle with the parameter of experiment in the molecular beam, including the impact parameter and the velocity are discussed. This theoretical model is important to understand or perform the experiment in the molecular beam.

  3. Collagen fiber angle in the submucosa of small intestine and its application in gastroenterology

    Institute of Scientific and Technical Information of China (English)

    Yan-Jun Zeng; Ai-Ke Qiao; Ji-Dong Yu; Jing-Bo Zhao; Dong-Hua Liao; Xiao-Hu Xu; Gregersen Hans

    2003-01-01

    AIM: To propose a simple and effective method suitable for analyzing the angle and distribution of 2-dimensional collagen fiber in larger sample of small intestine and to investigate the relationship between the angles of collagen fiber and the pressure it undergoes.METHODS: A kind of 2-dimensional visible quantitative analyzing technique was described. Digital image-processing method was utilized to determine the angle of collagen fiber in parenchyma according to the changes of area analyzed and further to investigate quantitatively the distribution of collagen fiber. A series of intestinal slice′s images preprocessed by polarized light were obtained with electron microscope,and they were processed to unify each pixel. The approximate angles between collagen fibers were obtained via analyzing the images and their corresponding polarized light. The relationship between the angles of collagen fiber and the pressure it undergoes were statistically summarized.RESULTS: The angle of collagen fiber in intestinal tissue was obtained with the quantitative analyzing method of calculating the ratio of different pixels. For the same slice,with polarized light angle′s variation, the corresponding ratio of different pixels was also changed; for slices under different pressures, the biggest ratio of collagen fiber area was changed either.CONCLUSION: This study suggests that the application of stress on the intestinal tissue will change the angle and content of collagen fiber. The method of calculating ratios of different pixel values to estimate collagen fiber angle was practical and reliable. The quantitative analysis used in the present study allows a larger area of soft tissue to be analyzed with relatively low cost and simple equipment.

  4. Note: A gel based imaging technique of the iridocorneal angle for evaluation of angle-closure glaucoma

    Science.gov (United States)

    Shinoj, V. K.; Murukeshan, V. M.; Baskaran, M.; Aung, T.

    2014-06-01

    Noninvasive medical imaging techniques have high potential in the field of ocular imaging research. Angle closure glaucoma is a major disease causing blindness and a possible way of detection is the examination of the anterior chamber angle in eyes. Here, a simple optical method for the evaluation of angle-closure glaucoma is proposed and illustrated. The light propagation from the region associated with the iridocorneal angle to the exterior of eye is considered analytically. The design of the gel assisted probe prototype is carried out and the imaging of iridocorneal angle is performed on an eye model.

  5. Multi-angle Imaging SpectroRadiometer

    Science.gov (United States)

    Diner, David J. (Principal Investigator)

    MISR views the sunlit Earth simultaneously at nine widely spaced angles and provides ongoing global coverage with high spatial detail. Its imagery is carefully calibrated to provide accurate measures of the brightness, contrast, and color of reflected sunlight. MISR provides new types of information for scientists studying Earth's climate, such as the regional and global distribution of different types of atmospheric particles and aerosols. The change in reflection at different view angles provides the means to distinguish aerosol types, cloud forms, and land surface cover. Combined with stereoscopic techniques, this enables construction of 3-D cloud models and estimation of the total amount of sunlight reflected by Earth's diverse environments. MISR was built for NASA by the Jet Propulsion Laboratory (JPL) in Pasadena, California. It is part of NASA's first Earth Observing System (EOS) spacecraft, the Terra spacecraft, which was launched into polar orbit from Vandenberg Air Force Base on December 18, 1999. MISR has been continuously providing data since February 24, 2000. [Mission Objectives] The MISR instrument acquires systematic multi-angle measurements for global monitoring of top-of-atmosphere and surface albedos and for measuring the shortwave radiative properties of aerosols, clouds, and surface scenes in order to characterize their impact on the Earth's climate. The Earth's climate is constantly changing -- as a consequence of both natural processes and human activities. Scientists care a great deal about even small changes in Earth's climate, since they can affect our comfort and well-being, and possibly our survival. A few years of below-average rainfall, an unusually cold winter, or a change in emissions from a coal-burning power plant, can influence the quality of life of people, plants, and animals in the region involved. The goal of NASA's Earth Observing System (EOS) is to increase our understanding of the climate changes that are occurring on our

  6. Ternary Free Energy Lattice Boltzmann Model with Tunable Surface Tensions and Contact Angles

    CERN Document Server

    Semprebon, Ciro; Kusumaatmaja, Halim

    2015-01-01

    We present a new ternary free energy lattice Boltzmann model. The distinguishing feature of our model is that we are able to analytically derive and independently vary all fluid-fluid surface tensions and the solid surface contact angles. We carry out a number of benchmark tests: (i) double emulsions and liquid lenses to validate the surface tensions, (ii) ternary fluids in contact with a square well to compare the contact angles against analytical predictions, and (iii) ternary phase separation to verify that the multicomponent fluid dynamics is accurately captured. Additionally we also describe how the model here presented here can be extended to include an arbitrary number of fluid components.

  7. The correlation of multi-angle thermal infrared data and the choice of optimal view angles

    Institute of Scientific and Technical Information of China (English)

    FAN; Wenjie; XU; Xiru

    2004-01-01

    Based on the matrix formula of thermal infrared radiant system, the components temperature can be retrieved by the inversive matrix. Around the stability problem of retrieved result, the research work we did was focused on (i) the correlation of (wk,j) which is the key to affect the retrieval accuracy, (ii) a general method which can help us find the number of retrievable parameters and evaluate the retrieval error before its performance, (iii) the choice of "optimal viewing angle group" based on the formula of absolute error propagation. The row winter wheat field was chosen as an example. The results can provide a theoretical basis for multi-angle thermal infrared remote sensing and components temperature retrieval.

  8. Angle-of-arrival fluctuations in moderate to strong turbulence

    Institute of Scientific and Technical Information of China (English)

    Ma Jing; Gao Chong; Tan Li-Yi

    2007-01-01

    Based on the modified spectrum, the analytic expressions for the variance and normalized covariance of angle-of-arrival (AOA) fluctuations are presented, which are applicable to the weak and strong regimes. The experimental data of AOA fluctuations validate the new derived expressions in weak and strong regimes. The results show that the receiving aperture D, outer scale and cell scale larger than the scattering disc S contribute significantly to the AOA fluctuations, and contributions from the small-scale turbulence are negligible. For the case of 4S/D <<1, the receiving aperture dominates low-pass filtering effects and the new displacement variances are in good agreement with the results from the old weak-fluctuation theory. For the case of 4S/D>>1, the scattering disc dominates the low-pass filtering effects and the new displacement variances depart from the results from the old weak-fluctuation theory.

  9. Experience in applying the critical angle of reflectivity in NDT

    Science.gov (United States)

    Brokowski, A.; Deputat, J.

    1980-12-01

    Experience gained in the application of the critical angle of reflectivity technique as realized by an ultrasonic goniometer is reviewed. The goniometer is described as a one-probehead unit operating in the echo regime, and the operating principles of the device, which measures changes in the height of ultrasonic echos reflected from a sample-water interface as a function of sample rotation, are discussed. Examples of the application of the goniometer to determinations of the tensile strength of cast iron, the extent of cold working of stainless steel, the texture of rolled materials, extents of heat treatment, the hardness and velocity profiles of a cementation layer, surface layer thicknesses, and stresses in steels, and to the testing of bond quality and ceramics, semiconductors and plastics are presented.

  10. Shape measurement of aspheric plastic lens with large angle

    Institute of Scientific and Technical Information of China (English)

    Dagang Huang; Heng Zhang; Shah-Rong Lee; Baoguang Wang

    2005-01-01

    @@ In this paper, according to the features of easy distortion and scratch for aspheric plastic lens, a noncontact measuring method is raised to test error in shape of the lens. Namely, the distance between a template and its image reflected with tested lens can be measured in nearly the vertical direction of the lens axis when the two-dimensional (2D) template is put near the measured surface. Then, the outline of the central cross-section could be obtained by calculating and curve fitting. Furthermore, three-dimensional (3D) surface can be imitated through rotating the component. A new fitting method of drift measurement is presented to prevent reducing precision when the lens and the template are fixed. The template is adjusted according to the position of the lens. The measurement precision is in the order of magnitued of sub-microns. Rotationally symmetric convex aspheric surface with any angle can be measured by this method.

  11. ATLAS, and Wide-Angle Tail Galaxies in ATLAS

    Indian Academy of Sciences (India)

    Minnie Y. Mao; Rob Sharp; D. J. Saikia; Ray P. Norris; Melanie Johnston-Hollitt; Enno Middelberg; Jim E. J. Lovell

    2011-12-01

    Using the Australia Telescope Compact Array (ATCA), ATLAS (Australia Telescope Large Area Survey) is imaging two fields totalling 7 square degrees down to 10 Jy beam-1 at 1.4 GHz. We have found 6 wide-angle tail galaxies (WATs), 4 of which have sufficient data to identify associated galaxy overdensities. The largest WAT, at a red-shift of 0.22, appears to be associated with an overdensity of galaxies that is spread over an unusually large extent of 12Mpc, with a velocity range of 4500 km s-1. Here we present the WATs in ATLAS and discuss the implications of these observations for future large-scale radio surveys such as ASKAP-EMU.

  12. Molecular complexity of primary open angle glaucoma: current concepts

    Indian Academy of Sciences (India)

    Kunal Ray; Suddhasil Mookherjee

    2009-12-01

    Glaucoma is a group of heterogeneous optic neuropathies with complex genetic basis. Among the three principle subtypes of glaucoma, primary open angle glaucoma (POAG) occurs most frequently. Till date, 25 loci have been found to be linked to POAG. However, only three underlying genes (Myocilin, Optineurin and WDR36) have been identified. In addition, at least 30 other genes have been reported to be associated with POAG. Despite strong genetic influence in POAG pathogenesis, only a small part of the disease can be explained in terms of genetic aberration. Current concepts of glaucoma pathogenesis suggest it to be a neurodegenerative disorder which is triggered by different factors including mechanical stress due to intra-ocular pressure, reduced blood flow to retina, reperfusion injury, oxidative stress, glutamate excitotoxicity, and aberrant immune response. Here we present a mechanistic overview of potential pathways and crosstalk between them operating in POAG pathogenesis.

  13. Optimal directional view angles for remote-sensing missions

    Science.gov (United States)

    Kimes, D. S.; Holben, B. N.; Tucker, C. J.; Newcomb, W. W.

    1984-01-01

    The present investigation is concerned with the directional, off-nadir viewing of terrestrial scenes using remote-sensing systems from aircraft and satellite platforms, taking into account advantages of such an approach over strictly nadir viewing systems. Directional reflectance data collected for bare soil and several different vegetation canopies in NOAA-7 AVHRR bands 1 and 2 were analyzed. Optimum view angles were recommended for two strategies. The first strategy views the utility of off-nadir measurements as extending spatial and temporal coverage of the target area. The second strategy views the utility of off-nadir measurements as providing additional information about the physical characteristics of the target. Conclusions regarding the two strategies are discussed.

  14. A novel small-angle neutron scattering detector geometry

    Science.gov (United States)

    Kanaki, Kalliopi; Jackson, Andrew; Hall-Wilton, Richard; Piscitelli, Francesco; Kirstein, Oliver; Andersen, Ken H.

    2013-01-01

    A novel 2π detector geometry for small-angle neutron scattering (SANS) applications is presented and its theoretical performance evaluated. Such a novel geometry is ideally suited for a SANS instrument at the European Spallation Source (ESS). Motivated by the low availability and high price of 3He, the new concept utilizes gaseous detectors with 10B as the neutron converter. The shape of the detector is inspired by an optimization process based on the properties of the conversion material. Advantages over the detector geometry traditionally used on SANS instruments are discussed. The angular and time resolutions of the proposed detector concept are shown to satisfy the requirements of the particular SANS instrument. PMID:24046504

  15. Photoproduction of Pseudoscalar Mesons off Nuclei at Forward Angles

    CERN Document Server

    Gevorkyan, S; Gan, L; Larin, I; Khandaker, M

    2009-01-01

    With the advent of new photon tagging facilities and novel experimental technologies it has become possible to perform photoproduction cross section measurements of pseudoscalar mesons on nuclei with a percent level accuracy. The extraction of the radiative decay widths from these measurements at forward angles is done by the Primakoff method, which requires theoretical treatment of all processes participating in these reactions at the same percent level. In this work we review the theoretical approach to meson photoproduction amplitudes in the electromagnetic and strong fields of nuclei at forward direction. The most updated description of these processes are presented based on the Glauber theory of multiple scattering. In particular, the effects of final state interactions, corrections for light nuclei, and photon shadowing in nuclei are discussed.

  16. Mapping of low flip angles in magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Balezeau, Fabien; Saint-Jalmes, Herve [LTSI, INSERM U642, Universite Rennes 1 (France); Eliat, Pierre-Antoine [PRISM, IFR 140, Universite Rennes 1 (France); Cayamo, Alejandro Bordelois, E-mail: fabien.balezeau@gmail.com [Centro De BiofIsika Medica, Universidad de Oriente, Santiago de Cuba (Cuba)

    2011-10-21

    Errors in the flip angle have to be corrected in many magnetic resonance imaging applications, especially for T1 quantification. However, the existing methods of B1 mapping fail to measure lower values of the flip angle despite the fact that these are extensively used in dynamic acquisition and 3D imaging. In this study, the nonlinearity of the radiofrequency (RF) transmit chain, especially for very low flip angles, is investigated and a simple method is proposed to accurately determine both the gain of the RF transmitter and the B1 field map for low flip angles. The method makes use of the spoiled gradient echo sequence with long repetition time (TR), such as applied in the double-angle method. It uses an image acquired with a flip angle of 90{sup 0} as a reference image that is robust to B1 inhomogeneity. The ratio of the image at flip angle alpha to the image at a flip angle of 90{sup 0} enables us to calculate the actual value of alpha. This study was carried out at 1.5 and 4.7 T, showing that the linearity of the RF supply system is highly dependent on the hardware. The method proposed here allows us to measure the flip angle from 1{sup 0} to 60{sup 0} with a maximal uncertainty of 10% and to correct T1 maps based on the variable flip angle method.

  17. Moderate positive spin Hall angle in uranium

    Science.gov (United States)

    Singh, Simranjeet; Anguera, Marta; del Barco, Enrique; Springell, Ross; Miller, Casey W.

    2015-12-01

    We report measurements of spin pumping and the inverse spin Hall effect in Ni80Fe20/uranium bilayers designed to study the efficiency of spin-charge interconversion in a super-heavy element. We employ broad-band ferromagnetic resonance on extended films to inject a spin current from the Ni80Fe20 (permalloy) into the uranium layer, which is then converted into an electric field by the inverse spin Hall effect. Surprisingly, our results suggest a spin mixing conductance of order 2 × 1019 m-2 and a positive spin Hall angle of 0.004, which are both merely comparable with those of several transition metals. These results thus support the idea that the electronic configuration may be at least as important as the atomic number in governing spin pumping across interfaces and subsequent spin Hall effects. In fact, given that both the magnitude and the sign are unexpected based on trends in d-electron systems, materials with unfilled f-electron orbitals may hold additional exploration avenues for spin physics.

  18. Moderate positive spin Hall angle in uranium

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Simranjeet; Anguera, Marta; Barco, Enrique del, E-mail: delbarco@ucf.edu, E-mail: cwmsch@rit.edu [Department of Physics, University of Central Florida, Orlando, Florida 32816 (United States); Springell, Ross [H. H. Will Laboratory, University of Bristol, Bristol BS2 8BS (United Kingdom); Miller, Casey W., E-mail: delbarco@ucf.edu, E-mail: cwmsch@rit.edu [School of Chemistry and Materials Science, Rochester Institute of Technology, Rochester, New York 14623 (United States)

    2015-12-07

    We report measurements of spin pumping and the inverse spin Hall effect in Ni{sub 80}Fe{sub 20}/uranium bilayers designed to study the efficiency of spin-charge interconversion in a super-heavy element. We employ broad-band ferromagnetic resonance on extended films to inject a spin current from the Ni{sub 80}Fe{sub 20} (permalloy) into the uranium layer, which is then converted into an electric field by the inverse spin Hall effect. Surprisingly, our results suggest a spin mixing conductance of order 2 × 10{sup 19} m{sup −2} and a positive spin Hall angle of 0.004, which are both merely comparable with those of several transition metals. These results thus support the idea that the electronic configuration may be at least as important as the atomic number in governing spin pumping across interfaces and subsequent spin Hall effects. In fact, given that both the magnitude and the sign are unexpected based on trends in d-electron systems, materials with unfilled f-electron orbitals may hold additional exploration avenues for spin physics.

  19. Significant relationship between local angle at fused segments and C2-7 angle: Average duration of longer than 20 years after anterior cervical discectomy and fusion

    Directory of Open Access Journals (Sweden)

    T Nagata

    2011-01-01

    Full Text Available Background : The authors have focused their attention to the radiological durability of cervical sagittal alignment after anterior cervical discectomy and fusion (ACDF using autologous bone grafting. Materials and Methods : Among the patients who underwent ACDF with trans-unco-discal (TUD approach between 1976 and 1997, 22 patients (16 males and 6 females made return visits for a clinical evaluation. Patients with trauma or previously treated by anterior cervical fusion or by posterior decompression were excluded from the present study. Clinical evaluation included adjacent segment degeneration (ASD, osseous fusion, local angle at the fused segments and C2-7 angle of cervical spine. Results : The duration after ACDF ranged from 13 to 34 years with an average of 21.3 ± 7.0 years. A single level fusion was done on 8 patients, 2 levels on 11 patients, 3 levels on 2 patients, and 4 levels on 1 patient. Imaging studies indicated that 12 of the 22 patients (54.5% were graded as having symptomatic ASD. Osseous bony fusion at ACDF was recognized in all cases. None of the patients demonstrated kyphotic malalignment of the cervical spine. Average degrees of local angle at the fused segments and the C2-7 angle were 7.06 and 17.6, respectively. Statistical analysis indicated a significant relationship between the local at the fused segments and C2-7 angles. Conclusions : Sagittal alignment of the cervical spine was durable long after ACDF when the local angle at the fused segments was well stabilized.

  20. A Numerical Dynamic Contact Angle Model Applied to Droplets Sliding Down An Incline

    Science.gov (United States)

    Afkhami, Shahriar; Bussmann, Markus

    2007-11-01

    A numerical dynamic contact angle model based on a well-known hydrodynamic theory is developed for the imposition of a boundary condition at the contact line. The efficacy of this new model is demonstrated via 3D examples of a viscous droplet sliding down a partially wetting incline. As experimentally observed (Phys. Rev. Lett. 87 (2001), 036102), when the inclination angle increases, the rear of the drop becomes elongated until it develops a ``corner'' which eventually breaks up into smaller droplets, while the leading edge of the drop remains rounded. Using the open source code ``Gerris'' (http://gfs.sf.net), we present the results of droplets sliding on an inclined plane. A similar behaviour (asymmetry between advancing and receding contact lines) is demonstrated. Results are in qualitative agreement with experimental observations. The role of surface inclination on the distribution of the dynamic contact angle along the droplet perimeter is also presented.

  1. Proceedings of the International school and symposium on small angle scattering

    International Nuclear Information System (INIS)

    The meeting was devoted to small angle neutron and X-ray scattering with regard to the wide interest for this method in various fields of basic and applied research. Scientists from European laboratories gave introductory talks to various subject fields related to small angle scattering (SAS) techniques or data analysis methods as well as topical research area e.g. soft condensed matter, biology or materials science. An important number of contributed talks were presented on neutron or X-ray scattering and even on combining both of them, demonstrating the very useful complementarity of these methods. Some other papers give nice examples of SAS experiments completed by results of other techniques such as NMRE of light scattering. The variety of presented contributions is a nice demonstration for the interdisciplinary use of small angle scattering from physics through biology, chemistry, materials science to engineering. 18 items are indexed separately for the INIS database. (K.A.)

  2. [The effect of crystalline lens extraction on intraocular pressure in patients with primary open-angle glaucoma].

    Science.gov (United States)

    Macarie, S; Macarie, Daniela

    2013-01-01

    This issue presents the results of a study on patients with cataract and primary open angle glaucoma who suffered lens extraction for cataract. We analise the effects of the lens extraction on the level of intraocular pressure at this patients.

  3. Comparison of Debrecen and Mount Wilson/Kodaikanal sunspot group tilt angles and the Joy's law

    Science.gov (United States)

    Baranyi, T.

    2015-02-01

    The study of active region tilt angles and their variations in different time-scales plays an important role in revealing the subsurface dynamics of magnetic flux ropes and in understanding the dynamo mechanism. In order to reveal the exact characteristics of tilt angles, precise long-term tilt angle data bases are needed. However, there are only a few different data sets at present, which are difficult to be compared and cross-calibrate because of their substantial deviations. In this paper, we describe new tilt angle data bases derived from the Debrecen Photoheliographic Data (DPD) (1974-) and from the SOHO/MDI-Debrecen Data (SDD) (1996-2010) sunspot catalogues. We compare them with the traditional sunspot group tilt angle data bases of Mount Wilson Observatory (1917-85) and Kodaikanal Solar Observatory (1906-87) and we analyse the deviations. Various methods and filters are investigated which may improve the sample of data and may help in deriving better results based on combined data. As a demonstration of the enhanced quality of the improved data set a refined diagram of Joy's law is presented.

  4. Luminosity Anti-leveling with Crossing Angle (MD 1669)

    CERN Document Server

    Gorzawski, Arkadiusz; Ponce, Laurette; Salvachua Ferrando, Belen Maria; Wenninger, Jorg; CERN. Geneva. ATS Department

    2016-01-01

    A significant fraction of the LHC luminosity ($\\sim$30\\% in 2016) is lost due to the presence (and necessity) of the crossing angles at the IPs. At the LHC the crossing angle is typically set to a value that provides sufficient separation of the beams at the start of fills for the peak bunch intensities. As the bunch intensity decays during a fill, it is possible to reduce the crossing angle and recover some luminosity. A smooth crossing angle reduction procedure must be developed to take advantage of this option during stable beam operation. During this MD a smooth procedure for luminosity leveling with crossing angle was tested. It was demonstrated that the orbit was well controlled, beam losses were low and the offset leveled experiments ALICE and LHCb were not affected by crossing angle leveling in ATLAS and CMS.

  5. Design Estimation of Aerodynamic Angles of High Speed Cars

    Directory of Open Access Journals (Sweden)

    Debojyoti Mitra

    2010-05-01

    Full Text Available The study of aerodynamic design of high-speed cars is mainly based on the wind-tunnel experiments and computational methods till date. In this particular study three car models of 100,200,300 pitch angles and 500,600,700 yaw angles are employed, and by wind-tunnel experiments we obtain pressure distributions over them. Now the correlations between drag-coefficient, lift-coefficient, pitch-angle and yaw-angle with Reynolds number are obtained by regression analysis of experimental data using MATLAB software. After plotting graphs it can be concluded that for minimum aerodynamic drag the optimized value of pitch and yaw angle should be 300 and 500. This type of study is expected to give a fair idea of aerodynamic angle design of high-speed cars.

  6. Contact pressure distribution and support angle optimization of kiln tyre

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    According to the shearing force character and the deformation coordination condition of shell at the station of supports, the mathematical models to calculate contact angle and contact pressure distribution between tyre and shell were set up, the formulae of bending moment and bending stress of tyre were obtained. Taking the maximum of tyre fatigue life as the optimal objective, the optimization model of tyre support angle was built. The computational results show that when tyre support angle is 30°, tyre life is far less than that when tyre support angle is optimal, which is 35.6°, and it is unsuitable to stipulate tyre support angle to be 30° in traditional design. The larger the load, the less the nominal stress amplitude increment of tyre, the more favorable the tyre fatigue life when tyre support angle is optimal.

  7. Sunspot group tilt angle measurements from historical observations

    CERN Document Server

    Pavai, V Senthamizh; Diercke, A; Denker, C; Vaquero, J M

    2016-01-01

    Sunspot positions from various historical sets of solar drawings are analysed with respect to the tilt angles of bipolar sunspot groups. Data by Scheiner, Hevelius, Staudacher, Zucconi, Schwabe, and Spoerer deliver a series of average tilt angles spanning a period of 270 years, additional to previously found values for 20th-century data obtained by other authors. We find that the average tilt angles before the Maunder minimum were not significantly different from the modern values. However, the average tilt angles of a period 50 years after the Maunder minimum, namely for cycles 0 and 1, were much lower and near zero. The normal tilt angles before the Maunder minimum suggest that it was not abnormally low tilt angles which drove the solar cycle into a grand minimum.

  8. The Art of Presenting.

    Science.gov (United States)

    Lukey-Coutsocostas, Kathryn; Tanner-Bogia, Julia

    1998-01-01

    Provides suggestions for helping nonnative English speakers in planning and delivering an effective presentation. Topics covered include the following: fears, choosing a topic, planning, title/summary/abstract, equipment, delivery, and evaluation of the present. (Author/VWL)

  9. Workshop Presentations: Overviews

    Data.gov (United States)

    National Aeronautics and Space Administration — These slides were presented at the AePW, April 21-22, 2012. Additional presentations can be found on each of the associated analysis webpages. Separate pages...

  10. Presenting Food Science Effectively

    Science.gov (United States)

    Winter, Carl K.

    2016-01-01

    While the need to present food science information effectively is viewed as a critical competency for food scientists by the Institute of Food Technologists, most food scientists may not receive adequate training in this area. Effective presentations combine both scientific content and delivery mechanisms that demonstrate presenter enthusiasm for…

  11. Transition radiation produced in dihedral and trihedral angles

    Energy Technology Data Exchange (ETDEWEB)

    Serov, A.V. [P.N. Lebedev Physical Institute, RAS, 119991 Moscow (Russian Federation)], E-mail: servo@x4u.lebedev.ru; Bolotovskii, B.M. [P.N. Lebedev Physical Institute, RAS, 119991 Moscow (Russian Federation)

    2008-09-15

    Method of electrical images is applied to the description of transition radiation generated when a charges particle passes through a dihedral angle formed by perfectly conducting planes. It is shown that the electromagnetic field generated when a charged particle passes through a dihedral angle {alpha} = {pi}/m is equivalent to the field generated by 2m charged particles which instantaneously start to move. Transition radiation in trihedral angle is also considered.

  12. Can a surgeon drill accurately at a specified angle?

    Science.gov (United States)

    Brioschi, Valentina; Cook, Jodie; Arthurs, Gareth I

    2016-01-01

    Objectives To investigate whether a surgeon can drill accurately a specified angle and whether surgeon experience, task repetition, drill bit size and perceived difficulty influence drilling angle accuracy. Methods The sample population consisted of final-year students (n=25), non-specialist veterinarians (n=22) and board-certified orthopaedic surgeons (n=8). Each participant drilled a hole twice in a horizontal oak plank at 30°, 45°, 60°, 80°, 85° and 90° angles with either a 2.5  or a 3.5 mm drill bit. Participants then rated the perceived difficulty to drill each angle. The true angle of each hole was measured using a digital goniometer. Results Greater drilling accuracy was achieved at angles closer to 90°. An error of ≤±4° was achieved by 84.5 per cent of participants drilling a 90° angle compared with approximately 20 per cent of participants drilling a 30–45° angle. There was no effect of surgeon experience, task repetition or drill bit size on the mean error for intended versus achieved angle. Increased perception of difficulty was associated with the more acute angles and decreased accuracy, but not experience level. Clinical significance This study shows that surgeon ability to drill accurately (within ±4° error) is limited, particularly at angles ≤60°. In situations where drill angle is critical, use of computer-assisted navigation or custom-made drill guides may be preferable. PMID:27547423

  13. Bilateral acute angle-closure glaucoma after dexfenfluramine treatment.

    Science.gov (United States)

    Denis, P; Charpentier, D; Berros, P; Touameur, S

    1995-01-01

    We report the case of a patient with narrow angles who had an attack of bilateral acute angle-closure glaucoma precipitated by dexfenfluramine, a serotoninergic drug developed for appetite suppression. Although the exact mechanism remains uncertain, the pupillary block observed in our case may be the result of the serotoninergic or indirect parasympatholytic properties of the drug on the iris sphincter muscle. Serotonergic psychoactive drugs should be prescribed cautiously in patients with known narrow angles and should be monitored by an ophthalmologist.

  14. Rotational Angle Measurement of Bridge Support Using Image Processing Techniques

    OpenAIRE

    Young-Soo Park; John Arbie Agbayani; Jong-Han Lee; Jong-Jae Lee

    2016-01-01

    Measuring a very small rotational angle accurately and dynamically is indeed a challenging issue, especially in the case of bridge support. Also, existing inclinometers do not have sufficient resolution and accuracy to measure a bridge’s rotational angle. In this study, a new measurement system was developed to provide a practical means for measuring dynamic rotational angle of a bridge support. It features high resolution and accuracy compared with the available systems on the market. By the...

  15. Mechanism and Etiology of Primary Chronic Angle Closure Glaucoma

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    The ocular anatomic features, pupil-blocking force, status of angle synechiae closure and positivity of provocative tests were compared between the primary chronic angle closure glaucoma (PCACG) and primary a-cute angle closure glaucoma (PAACG) by using ultrasonic biometry, computerized anterior ocular segment image processing technique, gonioscopy and provocative tests. The studies showed that the anterior chamber depth of PAACG was shallower than that of PCACG; the pupil-blocking force of PAACG was st...

  16. On extracting quark mixing angles in B meson decays

    International Nuclear Information System (INIS)

    After emphasizing the fundamental importance of determining the mixing angles of bottom quarks we list and discuss the considerable systematic uncertainties one faces when extracting these mixing angles from B decays. Evaluating various methods suggested we conclude that a study of the lepton energy spectrum in B decays provides a reasonable way of obtaining the ratio of mixing angles; yet in view of its inherent hazards its results should be backed up by other studies based, e.g., on kaon multiplicities

  17. Chapman Solar Zenith Angle variations at Titan

    Science.gov (United States)

    Royer, Emilie M.; Ajello, Joseph; Holsclaw, Gregory; West, Robert; Esposito, Larry W.; Bradley, Eric Todd

    2016-10-01

    Solar XUV photons and magnetospheric particles are the two main sources contributing to the airglow in the Titan's upper atmosphere. We are focusing here on the solar XUV photons and how they influence the airglow intensity. The Cassini-UVIS observations analyzed in this study consist each in a partial scan of Titan, while the center of the detector stays approximately at the same location on Titan's disk. We used observations from 2008 to 2012, which allow for a wide range of Solar Zenith Angle (SZA). Spectra from 800 km to 1200 km of altitude have been corrected from the solar spectrum using TIMED/SEE data. We observe that the airglow intensity varies as a function of the SZA and follows a Chapman curve. Three SZA regions are identified: the sunlit region ranging from 0 to 50 degrees. In this region, the intensity of the airglow increases, while the SZA decreases. Between SZA 50 and 100 degrees, the airglow intensity decreases from it maximum to its minimum. In this transition region the upper atmosphere of Titan changes from being totally sunlit to being in the shadow of the moon. For SZA 100 to 180 degrees, we observe a constant airglow intensity close to zero. The behavior of the airglow is also similar to the behavior of the electron density as a function of the SZA as observed by Ågren at al (2009). Both variables exhibit a decrease intensity with increasing SZA. The goal of this study is to understand such correlation. We demonstrate the importance of the solar XUV photons contribution to the Titan airglow and prove that the strongest contribution to the Titan dayglow occurs by solar fluorescence rather than the particle impact that predominates at night.

  18. Trigeminocardiac Reflex during Maxillary Reconstruction Surgery: A Case Report

    Directory of Open Access Journals (Sweden)

    Mayank Kulshrestha

    2014-03-01

    Full Text Available Systemic hypotension, cardiac dysrhythmia especially bradycardia, apnoea, and gastric hypermotility occurring presumably after stimulation of any of the sensory branches of trigeminal nerve is coined as trigeminocardiac reflex (TCR. It has been described to occur in various surgeries like cerebello-pontine angle and pituitary fossa surgeries. Such bradycardic reflex responses have also been observed during maxillofacial surgeries. The TCR presents as a challenge to both the Anaesthesiologist and the Surgeon in view of its varied presentations, diagnosis, prevention and appropriate management.

  19. Electronic structure of transferred graphene/h-BN van der Waals heterostructures with nonzero stacking angles by nano-ARPES

    Science.gov (United States)

    Wang, Eryin; Chen, Guorui; Wan, Guoliang; Lu, Xiaobo; Chen, Chaoyu; Avila, Jose; Fedorov, Alexei V.; Zhang, Guangyu; Asensio, Maria C.; Zhang, Yuanbo; Zhou, Shuyun

    2016-11-01

    In van der Waals heterostructures, the periodic potential from the Moiré superlattice can be used as a control knob to modulate the electronic structure of the constituent materials. Here we present a nanoscale angle-resolved photoemission spectroscopy (nano-ARPES) study of transferred graphene/h-BN heterostructures with two different stacking angles of 2.4° and 4.3° respectively. Our measurements reveal six replicas of graphene Dirac cones at the superlattice Brillouin zone (SBZ) centers. The size of the SBZ and its relative rotation angle to the graphene BZ are in good agreement with Moiré superlattice period extracted from atomic force microscopy (AFM) measurements. Comparison to the epitaxial graphene/h-BN with 0° stacking angles suggests that the interaction between graphene and h-BN decreases with increasing stacking angle.

  20. Innovative presentations for dummies

    CERN Document Server

    Anthony, Ray

    2014-01-01

    Be the speaker they follow with breakthrough innovative presentations Innovative Presentations For Dummies is a practical guide to engaging your audience with superior, creative, and ultra-compelling presentations. Using clear language and a concise style, this book goes way beyond PowerPoint to enable you to reimagine, reinvent, and remake your presentations. Learn how to stimulate, capture, and hold your audience in the palm of your hand with sound, sight, and touch, and get up to speed on the latest presentation design methods that make you a speaker who gets audiences committed and acting

  1. Laser Actuated Presentation System

    CERN Document Server

    Chowdhary, Atul; Karmakar, Subhajit; Sarkar, Sandip

    2009-01-01

    We present here a pattern sensitive PowerPoint presentation scheme. The presentation is actuated by simple patterns drawn on the presentation screen by a laser pointer. A specific pattern corresponds to a particular command required to operate the presentation. Laser spot on the screen is captured by a RGB webcam with a red filter mounted, and its location is identified at the blue layer of each captured frame by estimating the mean position of the pixels whose intensity is above a given threshold value. Measured Reliability, Accuracy and Latency of our system are 90%, 10 pixels (in the worst case) and 38 ms respectively.

  2. Laser Actuated Presentation System

    OpenAIRE

    Chowdhary, Atul; Agrawal, Vivek; Karmakar, Subhajit; Sarkar, Sandip

    2009-01-01

    We present here a pattern sensitive PowerPoint presentation scheme. The presentation is actuated by simple patterns drawn on the presentation screen by a laser pointer. A specific pattern corresponds to a particular command required to operate the presentation. Laser spot on the screen is captured by a RGB webcam with a red filter mounted, and its location is identified at the blue layer of each captured frame by estimating the mean position of the pixels whose intensity is above a given thre...

  3. Tibial and fibular angles in homozygous sickle cell disease

    Energy Technology Data Exchange (ETDEWEB)

    Akamaguna, A.I.; Odita, J.C.; Ugbodaga, C.I.; Okafor, L.A.

    1986-05-01

    Measurements of the tibial and fibular angles made on ankle radiographs of 34 patients with sickle cell disease were compared with those of 36 normal Nigerians. Widening of the fibular angle, which is an indication of tibiotalar slant, was demonstrated in about 79% of sickle cell disease patients. By using fibular angle measurements as an objective method of assessing subtle tibiotalar slant, it is concluded that the incidence of this deformity is much higher among sickle cell disease patients than previously reported. The mean values of tibial and fibular angles in normal Nigerians are higher than has been reported amongst Caucasians.

  4. Lateral intermetatarsal angle: a useful measurement of metatarsus primus elevatus?

    Science.gov (United States)

    Bryant, A; Mahoney, B; Tinley, P

    2001-05-01

    The lateral intermetatarsal angle, a measurement of the sagittal plane angular divergence between the dorsal cortices of the first and second metatarsals of lateral weightbearing foot radiographs, was compared in 30 normal and 30 hallux limitus feet. The results suggest that the angle may be measured reliably and that although the measured angles are relatively small, a significant difference exists between the normal and hallux limitus subjects studied. Accordingly, the lateral intermetatarsal angle may prove to be a useful radiographic measurement to assist the podiatric physician in the clinical assessment of hallux limitus. PMID:11359890

  5. Antibody elbow angles are influenced by their light chain class

    Energy Technology Data Exchange (ETDEWEB)

    Stanfield, R; Zemla, A; Wilson, I; Rupp, B

    2006-01-12

    We have examined the elbow angles for 365 different Fab fragments, and observe that Fabs with lambda light chains have adopted a wider range of elbow angles than their kappa-chain counterparts, and that the lambda light chain Fabs are frequently found with very large (>195{sup o}) elbow angles. This apparent hyperflexibility of lambda-chain Fabs may be due to an insertion in their switch region, which is one residue longer than in kappa chains, with glycine occurring most frequently at the insertion position. A new, web-based computer program that was used to calculate the Fab elbow angles is also described.

  6. Escape angles in bulk chi((2)) soliton interactions

    DEFF Research Database (Denmark)

    Johansen, Steffen Kjær; Bang, Ole; Sørensen, Mads Peter

    2002-01-01

    We develop a theory for nonplanar interaction between two identical type I spatial solitons propagating at opposite, but arbitrary transverse angles in quadratic nonlinear (or so-called chi((2))) bulk, media. We predict quantitatively the outwards escape angle, below which the solitons turn around...... and collide, and above which they continue to move-away from each other. For in-plane interaction, the theory allows prediction of the Outcome of a collision through the inwards escape angle, i.e., whether the solitons fuse or cross. We find an analytical expression determining the inwards escape angle using...... Gaussian approximations for the solitons. The theory is verified numerically....

  7. Aerodynamic performance of axial-flow fan stage operated at nine inlet guide vane angles. [to be used on vertical lift aircraft

    Science.gov (United States)

    Moore, R. D.; Reid, L.

    1979-01-01

    The overall performance of a fan stage with nine inlet guide vane angle settings is presented. These data were obtained over the stable flow range at speeds from 60 to 120 percent of design for vane setting angles from -25 to 42.5 degrees. At design speed and design inlet guide vane angle, the stage has a peak efficiency of 0.892 at a pressure ratio of 1.322 and a flow of 25.31 kg/s. The stall margin based on peak efficiency and stall was 20 percent. Based on an operating line passing through the peak efficiency point at the design setting angle, the useful operating range of the stage at design speed is limited by stall at the positive setting angles and by choke at the negative angles. At design the calculated static thrust along the operating line varied from 68 to 114 percent of that obtained at design setting angle.

  8. Calculation of contact angles at triple phase boundary in solid oxide fuel cell anode using the level set method

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xiaojun [Institute of Industrial Science, The University of Tokyo (Japan); Hasegawa, Yosuke [Institute of Industrial Science, The University of Tokyo (Japan); CREST, JST (Japan); Kohno, Haruhiko [Department of Mechanical Information Science and Technology, Kyushu Institute of Technology (Japan); Jiao, Zhenjun [Institute of Industrial Science, The University of Tokyo (Japan); CREST, JST (Japan); Hayakawa, Koji [Institute of Industrial Science, The University of Tokyo (Japan); Okita, Kohei [College of Industrial Technology, Nihon University (Japan); Shikazono, Naoki, E-mail: shika@iis.u-tokyo.ac.jp [Institute of Industrial Science, The University of Tokyo (Japan); CREST, JST (Japan)

    2014-10-15

    A level set method is applied to characterize the three dimensional structures of nickel, yttria stabilized zirconia and pore phases in solid oxide fuel cell anode reconstructed by focused ion beam-scanning electron microscope. A numerical algorithm is developed to evaluate the contact angles at the triple phase boundary based on interfacial normal vectors which can be calculated from the signed distance functions defined for each of the three phases. Furthermore, surface tension force is estimated from the contact angles by assuming the interfacial force balance at the triple phase boundary. The average contact angle values of nickel, yttria stabilized zirconia and pore are found to be 143°–156°, 83°–138° and 82°–123°, respectively. The mean contact angles remained nearly unchanged after 100 hour operation. However, the contact angles just after reduction are different for the cells with different sintering temperatures. In addition, standard deviations of the contact angles are very large especially for yttria stabilized zirconia and pore phases. The calculated surface tension forces from mean contact angles were close to the experimental values found in the literature. Slight increase of surface tensions of nickel/pore and nickel/yttria stabilized zirconia were observed after operation. Present data are expected to be used not only for the understanding of the degradation mechanism, but also for the quantitative prediction of the microstructural temporal evolution of solid oxide fuel cell anode. - Highlights: • A level set method is applied to characterize the 3D structures of SOFC anode. • A numerical algorithm is developed to evaluate the contact angles at the TPB. • Surface tension force is estimated from the contact angles. • The average contact angle values are found to be 143o-156o, 83o-138o and 82o-123o. • Present data are expected to understand degradation and predict evolution of SOFC.

  9. Behaviour of C-shaped angle shear connectors under monotonic and fully reversed cyclic loading: An experimental study

    International Nuclear Information System (INIS)

    Highlights: ► C-shaped angle connectors show 8.8–33.1% strength degradation under cyclic loading. ► Connector fracture type of failure was experienced in C-shaped angle shear connectors. ► In push-out samples, more cracking was observed in those slabs with longer angles. ► C-shaped angle connectors show good behaviour in terms of the ultimate shear capacity. ► C-shaped angle connectors did not fulfil the requirements for ductility criteria. -- Abstract: This paper presents an evaluation of the structural behaviour of C-shaped angle shear connectors in composite beams, suitable for transferring shear force in composite structures. The results of the experimental programme, including eight push-out tests, are presented and discussed. The results include resistance, strength degradation, ductility, and failure modes of C-shaped angle shear connectors, under monotonic and fully reversed cyclic loading. The results show that connector fracture type of failure was experienced in C-shaped angle connectors and after the failure, more cracking was observed in those slabs with longer angles. On top of that, by comparing the shear resistance of C-shaped angle shear connectors under monotonic and cyclic loading, these connectors showed 8.8–33.1% strength degradation, under fully reversed cyclic loading. Furthermore, it was concluded that the mentioned shear connector shows a proper behaviour, in terms of the ultimate shear capacity, but it does not satisfy the ductility criteria, imposed by the Eurocode 4, to perform a plastic distribution of the shear force between different connectors along the beam length.

  10. Brewster Angle Polarizing Beamsplitter Laser Damage Competition: P polarization

    Science.gov (United States)

    Stolz, Christopher J.; Runkel, Jeff

    2012-11-01

    Brewster angle plate polarizing beamsplitters play a critical role in splitting and combining beams within high power laser systems. A laser damage competition of polarizer beamsplitter coatings creates the opportunity to survey the current laser resistance these coatings within private industry, governmental institutions, and universities by a direct comparison of samples tested under identical conditions. The requirements of the coatings are a minimum transmission of 95% at "P" polarization and minimum reflection of 99% at "S" polarization at 1064 nm and 56.4 degrees angle of incidence. The choice of coating materials, design, and deposition method were left to the participant. Laser damage testing was performed according to the ISO 11254 standard utilizing a 1064 nm wavelength laser with a 10 ns pulse length operating at a repetition rate of 20 Hz. A double blind test assured sample and submitter anonymity so only a summary of the results are presented. In addition to the laser resistance results, details of cleaning methods, deposition processes, coating materials and layer count, and spectral results are also shared. Because of the large number of samples that were submitted, damage testing was conducted at "P" polarization only with "S" polarization damage testing reserved for next year on these submitted samples. Also the samples were only tested in the forward propagating direction; specifically samples were irradiated from air as the incident medium, through the thin film, and then through the substrate. In summary, a 6:1 difference existed for "P" polarization damage fluences amongst all of the competitors with the dominate variables that impacted the laser resistance being the deposition materials, deposition process, and cleaning method.

  11. Structural studies of ferrofluids by small-angle neutron scattering

    International Nuclear Information System (INIS)

    Ferrofluids or magnetic fluids - colloidal suspensions of single domain magnetic particles of about 100 A in diameter, stabilized with a surfactant shell in a suitable liquid carrier - are of current interest. One of the most powerful techniques involved is the small-angle neutron scattering (SANS). This is particularly suited to the study of magnetic colloids, because of the peculiar features of their magnetic interaction which enable the determination of the colloidal dispersion structure under a wide variety of experimental conditions. We present our investigations on ferrofluids performed on the YuMO small-angle neutron scattering diffractometer in function at the IBR-2 pulsed reactor at the Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear Research, Dubna, Russia and on the SANS diffractometer installed at WWR-SM steady reactor at the Research Institute for Solid State Physics and Optics, Budapest, Hungary. There can be investigated the structure of the particle, the aggregation phenomena, the magnetic liquid dynamics, particle-surfactant interaction, surfactant liquid-base interaction and structure, magnetic behavior of the samples. Ferrofluids exhibit a remarkably rich variety of behaviors and their study has been and still remains very active, since it is considered to open new technological frontiers. These materials are important for technological application as for their intrinsic physical properties, to understand and to improve the interesting macroscopic level, and to find how this structure is influenced by the action of certain parameters. Due to specific properties in a magnetic field they have been actively used in a lot of industrial, technical, as well as in biological and medical applications. (authors)

  12. A particle swarm optimization algorithm for beam angle selection in intensity-modulated radiotherapy planning

    International Nuclear Information System (INIS)

    Automatic beam angle selection is an important but challenging problem for intensity-modulated radiation therapy (IMRT) planning. Though many efforts have been made, it is still not very satisfactory in clinical IMRT practice because of overextensive computation of the inverse problem. In this paper, a new technique named BASPSO (Beam Angle Selection with a Particle Swarm Optimization algorithm) is presented to improve the efficiency of the beam angle optimization problem. Originally developed as a tool for simulating social behaviour, the particle swarm optimization (PSO) algorithm is a relatively new population-based evolutionary optimization technique first introduced by Kennedy and Eberhart in 1995. In the proposed BASPSO, the beam angles are optimized using PSO by treating each beam configuration as a particle (individual), and the beam intensity maps for each beam configuration are optimized using the conjugate gradient (CG) algorithm. These two optimization processes are implemented iteratively. The performance of each individual is evaluated by a fitness value calculated with a physical objective function. A population of these individuals is evolved by cooperation and competition among the individuals themselves through generations. The optimization results of a simulated case with known optimal beam angles and two clinical cases (a prostate case and a head-and-neck case) show that PSO is valid and efficient and can speed up the beam angle optimization process. Furthermore, the performance comparisons based on the preliminary results indicate that, as a whole, the PSO-based algorithm seems to outperform, or at least compete with, the GA-based algorithm in computation time and robustness. In conclusion, the reported work suggested that the introduced PSO algorithm could act as a new promising solution to the beam angle optimization problem and potentially other optimization problems in IMRT, though further studies need to be investigated

  13. Aerodynamic Investigation of Incidence Angle Effects in a Large Scale Transonic Turbine Cascade. Revision 1

    Science.gov (United States)

    McVetta, Ashlie B.; Giel, Paul W.; Welch, Gerard E.

    2014-01-01

    Aerodynamic measurements showing the effects of large incidence angle variations on an HPT turbine blade set are presented. Measurements were made in NASA's Transonic Turbine Blade Cascade Facility which has been used in previous studies to acquire detailed aerodynamic and heat transfer measurements for CFD code validation. The current study supports the development of variable-speed power turbine (VSPT) speed-change technology for the NASA Large Civil Tilt Rotor (LCTR) vehicle. In order to maintain acceptable main rotor propulsive efficiency, the VSPT operates over a nearly 50 percent speed range from takeoff to altitude cruise. This results in 50 deg or more variations in VSPT blade incidence angles. The cascade facility has the ability to operate over a wide range of Reynolds numbers and Mach numbers, but had to be modified in order to accommodate the negative incidence angle variation required by the LCTR VSPT operation. Using existing blade geometry with previously acquired aerodynamic data, the tunnel was re-baselined and the new incidence angle range was exercised. Midspan exit total pressure and flow angle measurements were obtained at seven inlet flow angles. For each inlet angle, data were obtained at five flow conditions with inlet Reynolds numbers varying from 6.83×10 (exp 5) to 0.85×10(exp 5) and two isentropic exit Mach numbers of 0.74 and 0.34. The midspan flowfield measurements were acquired using a three-hole pneumatic probe located in a survey plane 8.6 percent axial chord downstream of the blade trailing edge plane and covering three blade passages. Blade and endwall static pressure distributions were also acquired for each flow condition.

  14. Aerodynamic Investigation of Incidence Angle Effects in a Large Scale Transonic Turbine Cascade

    Science.gov (United States)

    McVetta, Ashlie B.; Giel, Paul W.; Welch, Gerard E.

    2013-01-01

    Aerodynamic measurements showing the effects of large incidence angle variations on an HPT turbine blade set are presented. Measurements were made in NASA's Transonic Turbine Blade Cascade Facility which has been used in previous studies to acquire detailed aerodynamic and heat transfer measurements for CFD code validation. The current study supports the development of variable-speed power turbine (VSPT) speed-change technology for the NASA Large Civil Tilt Rotor (LCTR) vehicle. In order to maintain acceptable main rotor propulsive efficiency, the VSPT operates over a nearly 50 percent speed range from takeoff to altitude cruise. This results in 50deg or more variations in VSPT blade incidence angles. The cascade facility has the ability to operate over a wide range of Reynolds numbers and Mach numbers, but had to be modified in order to accommodate the negative incidence angle variation required by the LCTR VSPT operation. Using existing blade geometry with previously acquired aerodynamic data, the tunnel was re-baselined and the new incidence angle range was exercised. Midspan exit total pressure and flow angle measurements were obtained at seven inlet flow angles. For each inlet angle, data were obtained at five flow conditions with inlet Reynolds numbers varying from 6.83×10(exp 5) to 0.85×10(exp 5) and two isentropic exit Mach numbers of 0.74 and 0.34. The midspan flowfield measurements were acquired using a three-hole pneumatic probe located in a survey plane 8.6 percent axial chord downstream of the blade trailing edge plane and covering three blade passages. Blade and endwall static pressure distributions were also acquired for each flow condition.

  15. Reliability and validity of goniometric and photographic measurements of clavicular tilt angle.

    Science.gov (United States)

    Ha, Sung-min; Kwon, Oh-yun; Weon, Jong-hyuck; Kim, Moon-hwan; Kim, Su-jung

    2013-10-01

    The aims of the present study were to assess the reliability of clavicular tilt angle measurement using goniometric and photographic measurements and to test the validity of the measurement by comparing the results with radiographic findings (gold standard). Clavicular tilt angles were measured in 18 healthy subjects (36 clavicles) using goniometric, photographic, and radiographic measurement. Repeated measurements using goniometric and photographic measurements were made in two test sessions conducted on different days by two examiners to assess inter-rater and intra-rater reliability of the two methods. Radiographic measurement was taken once, and the correlation between the radiographic findings and those of the indirect methods was calculated to test the validity of the goniometric and photographic measurement of clavicular tilt angle. No significant difference in clavicular tilt angle measurement was found between test sessions. The reliability of goniometric measurement (inter-rater intraclass correlation coefficients (ICC) = 0.85 (95% CI = 0.72-0.92) - 0.87 (95% CI = 0.77-0.87); intra-rater ICC = 0.80 (95% CI = 0.64-0.89)) and photographic measurement (inter-rater ICC = 0.89 (95% CI = 0.80-0.94) - 0.95 (95% CI = 0.91-0.98); intra-rater ICC = 0.84 (95% CI = 0.71-0.92) - 0.84 (95% CI = 0.69-0.91)) were excellent. The goniometric and photographic measurements of clavicular tilt angle were highly correlated with the radiographic findings (r = 0.83, 0.78, respectively). Goniometric and photographic measurements of clavicular tilt angle obtained by raters in this study may be considered reliable, and data obtained using the goniometric and photographic measurements are representative of radiographic findings of clavicular tilt angle.

  16. Posterior cerebral artery angle and the rupture of basilar tip aneurysms.

    Directory of Open Access Journals (Sweden)

    Allen L Ho

    Full Text Available Since the initial publication of the International Study of Unruptured Intracranial Aneurysms (ISUIA, management of unruptured intracranial aneurysms has been mainly based on the size of the aneurysm. The contribution of morphological characteristics to treatment decisions of unruptured aneurysms has not been well studied in a systematic and location specific manner. We present a large sample of basilar artery tip aneurysms (BTA that were assessed using a diverse array of morphological variables to determine the parameters associated with ruptured aneurysms. Demographic and clinical risk factors of aneurysm rupture were obtained from chart review. CT angiograms (CTA were evaluated with Slicer, an open source visualization and image analysis software, to generate 3-D models of the aneurysms and surrounding vascular architecture. Morphological parameters examined in each model included aneurysm volume, aspect ratio, size ratio, aneurysm angle, basilar vessel angle, basilar flow angle, and vessel to vessel angles. Univariate and multivariate analyses were performed to determine statistical significance. From 2008-2013, 54 patients with BTA aneurysms were evaluated in a single institution, and CTAs from 33 patients (15 ruptured, 18 unruptured were available and analyzed. Aneurysms that underwent reoperation, that were associated with arteriovenous malformations, or that lacked preoperative CTA were excluded. Multivariate logistic regression revealed that a larger angle between the posterior cerebral arteries (P1-P1 angle, p = 0.037 was most strongly associated with aneurysm rupture after adjusting for other morphological variables. In this location specific study of BTA aneurysms, the larger the angle formed between posterior cerebral arteries was found to be a new morphological parameter significantly associated with ruptured BTA aneurysms. This is a physically intuitive parameter that can be measured easily and readily applied in the clinical

  17. Leprosy neuropathy: clinical presentations.

    Science.gov (United States)

    Nascimento, Osvaldo J M

    2013-09-01

    Leprosy is a chronic infectious peripheral neuropathy caused by Mycobacterium leprae. The different clinical presentations of the disease are determined by the quality of the host immune response. Early detection of leprosy and treatment by multidrug therapy are the most important steps in preventing deformity and disability. Thus the early recognition of the clinical leprosy presentation is essential. Mononeuritis, mononeuritis multiplex (MM), polyneuritis (MM summation) are the most frequent. The frequent anesthetic skin lesions are absent in the pure neuritic leprosy presentation form. Isolated peripheral nerve involvement is common, including the cranial ones. Arthritic presentation is occasionally seen, usually misdiagnosed as rheumatoid arthritis. Attention should be given to autonomic dysfunctions in leprosy. There are clinical presentations with severe neuropathic pain - painful small-fiber neuropathy. Leprous late-onset neuropathy (LLON) clinical presentation should be considered facing a patient who develop an inflammatory neuropathy many years after a previous skin leprosy treatment. PMID:24141500

  18. Angles and Daemons: Spin Correlations at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Nhan V. [Johns Hopkins Univ., Baltimore, MD (United States)

    2011-09-01

    The Large Hadron Collider has recently started collecting data, opening a new energy regime. This will allow us to probe further than ever before many of the current mysteries of the field. New physics beyond the Standard Model, the field's current paradigm, could manifest itself via new particles. In addition, the Higgs boson, hypothesized as a consequence of electroweak symmetry breaking, remains undiscovered. At the time of discovery, the properties of such particles will be unknown. In order to understand the nature of any new physics, it will be important to understand the properties of that new particle. Methods are presented for measuring its spin, parity and coupling to the Standard Model particles. These methods are implemented at the Compact Muon Solenoid experiment and an analysis is presented with the data collected during 2010 and 2011 running at the Large Hadron Collider. An application of these techniques is used to make a measurement of the weak mixing angle. A current status of the search for the Higgs boson is also presented.

  19. Consistent Adjoint Driven Importance Sampling using Space, Energy and Angle

    Energy Technology Data Exchange (ETDEWEB)

    Peplow, Douglas E. [ORNL; Mosher, Scott W [ORNL; Evans, Thomas M [ORNL

    2012-08-01

    For challenging radiation transport problems, hybrid methods combine the accuracy of Monte Carlo methods with the global information present in deterministic methods. One of the most successful hybrid methods is CADIS Consistent Adjoint Driven Importance Sampling. This method uses a deterministic adjoint solution to construct a biased source distribution and consistent weight windows to optimize a specific tally in a Monte Carlo calculation. The method has been implemented into transport codes using just the spatial and energy information from the deterministic adjoint and has been used in many applications to compute tallies with much higher figures-of-merit than analog calculations. CADIS also outperforms user-supplied importance values, which usually take long periods of user time to develop. This work extends CADIS to develop weight windows that are a function of the position, energy, and direction of the Monte Carlo particle. Two types of consistent source biasing are presented: one method that biases the source in space and energy while preserving the original directional distribution and one method that biases the source in space, energy, and direction. Seven simple example problems are presented which compare the use of the standard space/energy CADIS with the new space/energy/angle treatments.

  20. CERN Electronics Pool presentations

    CERN Multimedia

    2011-01-01

    The CERN Electronics Pool has organised a series of presentations in collaboration with oscilloscope manufacturers. The last one will take place according to the schedule below.   Time will be available at the end of the presentation to discuss your personal needs. The Agilent presentation had to be postponed and will be organised later. -     Lecroy: Thursday, 24 November 2011, in 530-R-030, 14:00 to 16:30.

  1. Presentation skills for nurses.

    Science.gov (United States)

    Foulkes, Mark

    2015-02-20

    This article emphasises the importance of effective presentation skills. Such skills allow nurses to share knowledge and expertise and to communicate clearly in a range of workplace scenarios. Nurses are increasingly being asked to present in formal and informal situations, such as conferences, poster presentations, job interviews, case reports and ward-based teaching. This article explores the principles underpinning the development of these skills, discusses the situations in which they could be applied and demonstrates how nurses might improve and develop as presenters. PMID:25690236

  2. Presentation skills for nurses.

    Science.gov (United States)

    Foulkes, Mark

    2015-02-20

    This article emphasises the importance of effective presentation skills. Such skills allow nurses to share knowledge and expertise and to communicate clearly in a range of workplace scenarios. Nurses are increasingly being asked to present in formal and informal situations, such as conferences, poster presentations, job interviews, case reports and ward-based teaching. This article explores the principles underpinning the development of these skills, discusses the situations in which they could be applied and demonstrates how nurses might improve and develop as presenters.

  3. In situ microfluidic dialysis for biological small-angle X-ray scattering

    DEFF Research Database (Denmark)

    Skou, Magda; Skou, Soren; Jensen, Thomas Glasdam;

    2014-01-01

    Owing to the demand for low sample consumption and automated sample changing capabilities at synchrotron small-angle X-ray (solution) scattering (SAXS) beamlines, X-ray microfluidics is receiving continuously increasing attention. Here, a remote-controlled microfluidic device is presented for sim...

  4. Different moment-angle manifolds arising from two polytopes having the same bigraded Betti numbers

    OpenAIRE

    CHOI, SUYOUNG

    2012-01-01

    Two simple polytopes of dimension 3 having the identical bigraded Betti numbers but non-isomorphic Tor-algebras are presented. These polytopes provide two homotopically different moment-angle manifolds having the same bigraded Betti numbers. These two simple polytopes are the first examples of polytopes that are (toric) cohomologically rigid but not combinatorially rigid.

  5. Ultrasmall-angle X-ray scattering analysis of photonic crystal structure

    NARCIS (Netherlands)

    Abramova, V.V.; Sinitskii, A.S.; Grigoryeva, N.A.; Grigoriev, S.V.; Belov, D.V.; Petukhov, A.V.; Mistonov, A.A.; Vasilieva, A.V.; Tretyakov, Y.D.

    2009-01-01

    The results of an ultrasmall angle X ray scattering study of iron(III) oxide inverse opal thin films are presented. The photonic crystals examined are shown to have fcc structure with amount of stacking faults varying among the samples. The method used in this study makes it possible to easily disti

  6. Design and use of a 6 meter neutron small-angle scattering spectrometer at KUR

    Science.gov (United States)

    Komura, S.; Takeda, T.; Fujii, H.; Osamura, K.; Mochiki, K.; Hasegawa, K.

    1983-05-01

    A 6 meter neutron small-angle scattering spectrometer has been constructed at the Kyoto University Reactor (KUR) and has been used successfully in various fields of application. The design principles and the characteristics of the spectrometer are described briefly. Some examples of the scattering measurements are presented.

  7. Coulomb Correction to the Screening Angle of the Moliere Multiple Scattering Theory

    CERN Document Server

    Kuraev, E A; Tarasov, A V

    2012-01-01

    Coulomb correction to the screening angular parameter of the Moliere multiple scattering theory is found. Numerical calculations are presented in the range of nuclear charge from Z=4 to Z=82. Comparison with the approximate Moliere result for the screening angle reveals up to 30% deviation from it for sufficiently heavy elements of the target material.

  8. Calibration of a spinner anemometer for flow angle measurements by use of wind turbine yawing

    DEFF Research Database (Denmark)

    Demurtas, Giorgio; Friis Pedersen, Troels

    The present report describes a method to calibrate a spinner anemometer ow angle measurements. The turbine is yawed several times (5 times approximately 60 with respect to the wind direction) in steady wind (> 6 m/s) and measurements of yaw position (measured by a yaw position sensor) and yaw...

  9. Reversible membrane reorganizations during photosynthesis in vivo: revealed by small-angle neutron scattering

    DEFF Research Database (Denmark)

    Nagy, Gergely; Posselt, Dorthe; Kovacs, Laszlo;

    2011-01-01

    In the present study, we determined characteristic repeat distances of the photosynthetic membranes in living cyanobacterial and eukaryotic algal cells, and in intact thylakoid membranes isolated from higher plants with time-resolved small-angle neutron scattering. This non-invasive technique rev...

  10. Simulation of Canopy Leaf Inclination Angle in Rice

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-cui; LU Chuan-gen; HU Ning; YAO Ke-min; ZHANG Qi-jun; DAI Qi-gen

    2013-01-01

    A leaf inclination angle distribution model, which is applicable to simulate leaf inclination angle distribution in six heights of layered canopy at different growth stages, was established by component factors affecting plant type in rice. The accuracy of the simulation results was validated by measured values from a field experiment. The coefficient of determination (R2) and the root mean square error (RMSE) between the simulated and measured values were 0.9472 and 3.93%, respectively. The simulation results showed that the distribution of leaf inclination angles differed among the three plant types. The leaf inclination angles were larger in the compact variety Liangyoupeijiu with erect leaves than in the loose variety Shanyou 63 with droopy leaves and the intermediate variety Liangyou Y06. The leaf inclination angles were distributed in the lower range in Shanyou 63, which matched up with field measurements. The distribution of leaf inclination angles in the same variety changed throughout the seven growth stages. The leaf inclination angles enlarged gradually from transplanting to booting. During the post-booting period, the leaf inclination angle increased in Shanyou 63 and Liangyou Y06, but changed little in Liangyoupeijiu. At every growth stage of each variety, canopy leaf inclination angle distribution on the six heights of canopy layers was variable. As canopy height increased, the layered leaf area index (LAI) decreased in all the three plant types. However, while the leaf inclination angles showed little change in Liangyoupeijiu, they became larger in Shanyou 63 but smaller in Liangyou Y06. The simulation results used in the constructed model were very similar to the actual measurement values. The model provides a method for estimating canopy leaf inclination angle distribution in rice production.

  11. Role of Optical Coherence Tomography in Assessing Anterior Chamber Angles

    Science.gov (United States)

    Kochupurakal, Reema Thomas; Jha, Kirti Nath; Rajalakshmi, A.R.; Nagarajan, Swathi; Ezhumalai, G.

    2016-01-01

    Introduction Gonioscopy is the gold standard in assessing anterior chamber angles. However, interobserver variations are common and there is a need for reliable objective method of assessment. Aim To compare the anterior chamber angle by gonioscopy and Spectral Domain Optical Coherence Tomography (SD-OCT) in individuals with shallow anterior chamber. Materials and Methods This comparative observational study was conducted in a rural tertiary multi-speciality teaching hospital. A total of 101 eyes of 54 patients with shallow anterior chamber on slit lamp evaluation were included. Anterior chamber angle was graded by gonioscopy using the shaffer grading system. Angles were also assessed by SD-OCT with Trabecular Iris Angle (TIA) and Angle Opening Distance (AOD). Chi-square test, sensitivity, specificity, positive and negative predictive value to find correlation between OCT parameters and gonioscopy grading. Results Females represented 72.7%. The mean age was 53.93 ±8.24 years and mean anterior chamber depth was 2.47 ± 0.152 mm. Shaffer grade ≤ 2 were identified in 95(94%) superior, 42(41.5%) inferior, 65(64.3%) nasal and 57(56.4%) temporal quadrants. Cut-off values of TIA ≤ 22° and AOD ≤ 290 μm were taken as narrow angles on SD-OCT. TIA of ≤ 22° were found in 88(92.6%) nasal and 87(87%) temporal angles. AOD of ≤ 290 μm was found in 73(76.8%) nasal and 83(83%) temporal quadrants. Sensitivity in detecting narrow angles was 90.7% and 82.2% for TIA and AOD, while specificity was 11.7% and 23.4%, respectively. Conclusion Individuals were found to have narrow angles more with SD-OCT. Sensitivity was high and specificity was low in detecting narrow angles compared to gonioscopy, making it an unreliable tool for screening. PMID:27190851

  12. Free-vibration Characteristics of Laminated Angle-ply Non-circular Cylindrical Shells

    Directory of Open Access Journals (Sweden)

    M. Ganapathi

    2004-10-01

    Full Text Available This paper deals with the free-vibration behaviour of anisotropic laminated angle-ply noncircular cylindrical shells using finite element approach. The formulation is based on first-ordershear deformation theory. The present model accounts for in-plane and rotary inertia effects. A detailed study has been carried out to highlight the effects of shell geometry, cross-sectionalproperties, lay-up and ply-angles on the natural frequencies of different types of modes of vibration of non-circular elliptical shell structures.

  13. Nonlinear angle control of a sectioned airfoil by using shape memory alloys

    Directory of Open Access Journals (Sweden)

    Abreu G.

    2014-01-01

    Full Text Available The present work illustrates an application of shape memory alloys and nonlinear controller applied to the active angular control of a sectioned airfoil. The main objective of the proposed control system is to modify the shape of the profile based on a reference angle. The change of the sectioned airfoil angle is resultant by the effect of shape memory of the alloy due to heating of the wire caused by an electric current that changes its temperature by Joule effect. Considering the presence of plant’s nonlinear effects, especially in the mathematical model of the alloy, this work proposes the application of an on-off control system.

  14. Monte Carlo method of macroscopic modulation of small-angle charged particle reflection from solid surfaces

    CERN Document Server

    Bratchenko, M I

    2001-01-01

    A novel method of Monte Carlo simulation of small-angle reflection of charged particles from solid surfaces has been developed. Instead of atomic-scale simulation of particle-surface collisions the method treats the reflection macroscopically as 'condensed history' event. Statistical parameters of reflection are sampled from the theoretical distributions upon energy and angles. An efficient sampling algorithm based on combination of inverse probability distribution function method and rejection method has been proposed and tested. As an example of application the results of statistical modeling of particles flux enhancement near the bottom of vertical Wehner cone are presented and compared with simple geometrical model of specular reflection.

  15. Tunable-angle wedge transducer for improved acoustophoretic control in a microfluidic chip

    DEFF Research Database (Denmark)

    Iranmanesh, I.; Barnkob, Rune; Bruus, Henrik;

    2012-01-01

    coupling angle, and transducer actuation method (single-frequency actuation or frequency-modulation actuation). The energy-density analysis is based on measuring the transmitted light intensity through a microfluidic channel filled with a suspension of 5-μm-diameter beads and the results with the tunable...... particle patterns with average acoustic energy densities comparable to those obtained using single-frequency actuation.......We present a tunable-angle wedge ultrasound transducer for improved control of microparticle acoustophoresis in a microfluidic chip. The transducer is investigated by analyzing the pattern of aligned particles and induced acoustic energy density while varying the system geometry, transducer...

  16. Tunable-angle wedge transducer for improved acoustophoretic control in a microfluidic chip

    DEFF Research Database (Denmark)

    Iranmanesh, I.; Barnkob, Rune; Bruus, Henrik;

    2013-01-01

    coupling angle, and transducer actuation method (single-frequency actuation or frequency-modulation actuation). The energy-density analysis is based on measuring the transmitted light intensity through a microfluidic channel filled with a suspension of 5 µm diameter beads and the results with the tunable...... uniform particle patterns with average acoustic energy densities comparable to those obtained using single-frequency actuation.......We present a tunable-angle wedge ultrasound transducer for improved control of microparticle acoustophoresis in a microfluidic chip. The transducer is investigated by analyzing the pattern of aligned particles and induced acoustic energy density while varying the transducer geometry, transducer...

  17. The Availability of Radiological Measurement of Femoral Anteversion Angle: Three-Dimensional Computed Tomography Reconstruction

    OpenAIRE

    Byun, Ha Young; Shin, Heesuk; Lee, Eun Shin; Kong, Min Sik; Lee, Seung Hun; Lee, Chang Hee

    2016-01-01

    Objective To assess the intra-rater and inter-rater reliability for measuring femoral anteversion angle (FAA) by a radiographic method using three-dimensional computed tomography reconstruction (3D-CT). Methods The study included 82 children who presented with intoeing gait. 3D-CT data taken between 2006 and 2014 were retrospectively reviewed. FAA was measured by 3D-CT. FAA is defined as the angle between the long axis of the femur neck and condylar axis of the distal femur. FAA measurement w...

  18. ISW for the Treatment of Adult Angle Class I Crowding with Acceptable Lateral Profile Case

    OpenAIRE

    Tian-yu OU-YANG; Jian-hong YU; Tsai, Ya-Yu; Yu, Chien-Chih

    2015-01-01

    This article describes a 34-year-old adult female with chief complaint of poor dental alignment. She presented with Angle Class I crowding with acceptable lateral profile and had been treated with a non-extraction approach. The diagnosed after examination and analysis was Angle Class I malocclusion on Class I skeletal base with deep overbite and severe crowding. Treatment plan was carried out to preserve premolars and create space by using the MEAW technique, combined with ...

  19. Non-contact angle measurement based on parallel multiplex laser feedback interferometry

    International Nuclear Information System (INIS)

    We present a novel precise angle measurement scheme based on parallel multiplex laser feedback interferometry (PLFI), which outputs two parallel laser beams and thus their displacement difference reflects the angle variation of the target. Due to its ultrahigh sensitivity to the feedback light, PLFI realizes the direct non-contact measurement of non-cooperative targets. Experimental results show that PLFI has an accuracy of 8″ within a range of 1400″. The yaw of a guide is also measured and the experimental results agree with those of the dual-frequency laser interferometer Agilent 5529A. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  20. Unilateral Angle-Closure Glaucoma with Ciliochoroidal Effusion after the Consumption of Cannabis: A Case Report

    Directory of Open Access Journals (Sweden)

    Rana Hanna

    2014-12-01

    Full Text Available A 35-year-old male patient, diagnosed with acute angle-closure glaucoma, did not improve despite intensive treatment with antiglaucoma medications. Ultrasound biomicroscopy revealed a ciliochoroidal effusion. Due to his past history of drug abuse, a urine test was analyzed and found to be positive for cannabis. After topical cycloplegia and oral steroid therapy, his symptoms improved substantially. The present case highlights the role of ultrasound biomicroscopy in evaluating patients with acute angle-closure glaucoma and the role of cannabis abuse in the development of ciliochoroidal effusion.

  1. Unilateral angle-closure glaucoma with ciliochoroidal effusion after the consumption of cannabis: a case report.

    Science.gov (United States)

    Hanna, Rana; Tiosano, Beatrice; Dbayat, Noora; Gaton, Dan

    2014-01-01

    A 35-year-old male patient, diagnosed with acute angle-closure glaucoma, did not improve despite intensive treatment with antiglaucoma medications. Ultrasound biomicroscopy revealed a ciliochoroidal effusion. Due to his past history of drug abuse, a urine test was analyzed and found to be positive for cannabis. After topical cycloplegia and oral steroid therapy, his symptoms improved substantially. The present case highlights the role of ultrasound biomicroscopy in evaluating patients with acute angle-closure glaucoma and the role of cannabis abuse in the development of ciliochoroidal effusion. PMID:25606036

  2. 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.

  3. Effect of blade pitch angle on aerodynamic performance of straight-bladed vertical axis wind turbine

    Institute of Scientific and Technical Information of China (English)

    张立勋; 梁迎彬; 刘小红; 郭健

    2014-01-01

    Wind energy is one of the most promising renewable energy sources, straight-bladed vertical axis wind turbine (S-VAWT) appears to be particularly promising for the shortage of fossil fuel reserves owing to its distinct advantages, but suffers from poor self-starting and low power coefficient. Variable-pitch method was recognized as an attractive solution to performance improvement, thus majority efforts had been devoted into blade pitch angle effect on aerodynamic performance. Taken into account the local flow field of S-VAWT, mathematical model was built to analyze the relationship between power outputs and pitch angle. Numerical simulations on static and dynamic performances of blade were carried out and optimized pitch angle along the rotor were presented. Comparative analyses of fixed pitch and variable-pitch S-VAWT were conducted, and a considerable improvement of the performance was obtained by the optimized blade pitch angle, in particular, a relative increase of the power coefficient by more than 19.3%. It is further demonstrated that the self-starting is greatly improved with the optimized blade pitch angle.

  4. Multilevel Models for the Analysis of Angle-Specific Torque Curves with Application to Master Athletes

    Directory of Open Access Journals (Sweden)

    Carvalho Humberto M.

    2015-12-01

    Full Text Available The aim of this paper was to outline a multilevel modeling approach to fit individual angle-specific torque curves describing concentric knee extension and flexion isokinetic muscular actions in Master athletes. The potential of the analytical approach to examine between individual differences across the angle-specific torque curves was illustrated including between-individuals variation due to gender differences at a higher level. Torques in concentric muscular actions of knee extension and knee extension at 60°·s-1 were considered within a range of motion between 5°and 85° (only torques “truly” isokinetic. Multilevel time series models with autoregressive covariance structures with standard multilevel models were superior fits compared with standard multilevel models for repeated measures to fit anglespecific torque curves. Third and fourth order polynomial models were the best fits to describe angle-specific torque curves of isokinetic knee flexion and extension concentric actions, respectively. The fixed exponents allow interpretations for initial acceleration, the angle at peak torque and the decrement of torque after peak torque. Also, the multilevel models were flexible to illustrate the influence of gender differences on the shape of torque throughout the range of motion and in the shape of the curves. The presented multilevel regression models may afford a general framework to examine angle-specific moment curves by isokinetic dynamometry, and add to the understanding mechanisms of strength development, particularly the force-length relationship, both related to performance and injury prevention.

  5. Discharge Coefficient of 3-in-1 Hole with Various Inclination Angle and Hole Pitch

    Institute of Scientific and Technical Information of China (English)

    Li Guangchao; Zhu Huiren; Fan Huiming

    2008-01-01

    Discharge coefficients of 3-in- 1 hole of three inclination angles and three spacing between holes are presented which described the discharge behavior of a row of holes. The inlet and outlet of the 3-in-1 hole both have a 15° lateral expansion. The flow conditions considered are mainstream turbulence intensities and density ratios of secondary flow to mainstream. The momentum flux ratios varied in the range froom 1 to 4. The comparison is made of the discharge coefficients of three shaped holes to find an optimal hole with low flow loss. The results show that the discharge coefficients of 3-in-1 hole are highest in three shaped holes and therefore this article is focused on the measurements of discharge coefficients of 3-in-1 hole for various geometries and aerodynamic parameters. The measured results of 3-in-1 hole indicate that turbulence intensities, density ratios and momentum flux ratios have weak influence on discharge coefficients for inclination angle of 20°. The high turbulence intensity yields the small discharge coefficients for inclination angle of 45° and 90°.The increased both momentum flux ratios and density ratios lead to the increased discharge coefficients for inclination angle of 45° and 90°. The increased inclination angle causes the rapidly increased discharge coefficients. There is a weak dependence of discharge coefficients on hole pitches.

  6. Review of Advances in Cobb Angle Calculation and Image-Based Modelling Techniques for Spinal Deformities

    Science.gov (United States)

    Giannoglou, V.; Stylianidis, E.

    2016-06-01

    Scoliosis is a 3D deformity of the human spinal column that is caused from the bending of the latter, causing pain, aesthetic and respiratory problems. This internal deformation is reflected in the outer shape of the human back. The golden standard for diagnosis and monitoring of scoliosis is the Cobb angle, which refers to the internal curvature of the trunk. This work is the first part of a post-doctoral research, presenting the most important researches that have been done in the field of scoliosis, concerning its digital visualisation, in order to provide a more precise and robust identification and monitoring of scoliosis. The research is divided in four fields, namely, the X-ray processing, the automatic Cobb angle(s) calculation, the 3D modelling of the spine that provides a more accurate representation of the trunk and the reduction of X-ray radiation exposure throughout the monitoring of scoliosis. Despite the fact that many researchers have been working on the field for the last decade at least, there is no reliable and universal tool to automatically calculate the Cobb angle(s) and successfully perform proper 3D modelling of the spinal column that would assist a more accurate detection and monitoring of scoliosis.

  7. Estimating the helical pitch angle of amylopectin in starch using polarization second harmonic generation microscopy

    Science.gov (United States)

    Psilodimitrakopoulos, Sotiris; Amat-Roldan, Ivan; Loza-Alvarez, Pablo; Artigas, David

    2010-08-01

    Starch granules are among the brightest natural second harmonic generation (SHG) converters. They basically consist of amylose and amylopectin molecules and the source of the SHG signal is still undetermined. In the present study we perform polarization sensitive SHG (PSHG) imaging of wheat starch granules and we fit the SHG signal variation of each pixel of the PSHG images into a generalized biophysical model. By assuming that the SHG source molecule is a helix with cylindrical symmetry along its long axis, the model extracts the helical pitch angle of the SHG source for every pixel of the image. By displaying the pixel histogram representing this helical pitch angle we found a highly peaked histogram with maximum at θe = 36.1° and a width of Δθe = 9.3°. This pitch angle corresponds to the strand of the parallel double helical structure, called amylopectin (as measured by a small angle x-ray scattering technique). This demonstrates amylopectin (and not amylose) as the source of SHG in starch. According to our knowledge, this is the first estimation of the amylopectin's pitch angle in starch using PSHG.

  8. Switched-angle spinning applied to bicelles containing phospholipid-associated peptides

    Energy Technology Data Exchange (ETDEWEB)

    Zandomeneghi, Giorgia; Williamson, Philip T.F.; Hunkeler, Andreas; Meier, Beat H. [Physical Chemistry, ETH Zurich, ETH-Hoenggerberg (Switzerland)], E-mail: beme@ethz.ch

    2003-02-15

    In a model study, the proton NMR spectrum of the opioid pentapeptide leucine-enkephalin associated with bicelles is investigated. The spectral resolution for a static sample is limited due to the large number of anisotropic interactions, in particular strong proton-proton couplings, but resolution is greatly improved by magic-angle sample spinning. Here we present two-dimensional switched-angle spinning NMR experiments, which correlate the high-resolution spectrum of the membrane-bound peptide under magic-angle spinning with its anisotropic spectrum, leading to well-resolved spectra. The two-dimensional spectrum allows the exploitation of the high resolution of the isotropic spectrum, while retaining the structural information imparted by the anisotropic interactions in the static spectrum. Furthermore, switched-angle spinning techniques are demonstrated that allow one to record the proton spectrum of ordered bicellar phases as a function of the angle between the rotor axis and the magnetic field direction, thereby scaling the dipolar interactions by a predefined factor.

  9. Estimating the helical pitch angle of amylopectin in starch using polarization second harmonic generation microscopy

    International Nuclear Information System (INIS)

    Starch granules are among the brightest natural second harmonic generation (SHG) converters. They basically consist of amylose and amylopectin molecules and the source of the SHG signal is still undetermined. In the present study we perform polarization sensitive SHG (PSHG) imaging of wheat starch granules and we fit the SHG signal variation of each pixel of the PSHG images into a generalized biophysical model. By assuming that the SHG source molecule is a helix with cylindrical symmetry along its long axis, the model extracts the helical pitch angle of the SHG source for every pixel of the image. By displaying the pixel histogram representing this helical pitch angle we found a highly peaked histogram with maximum at θe = 36.1° and a width of Δθe = 9.3°. This pitch angle corresponds to the strand of the parallel double helical structure, called amylopectin (as measured by a small angle x-ray scattering technique). This demonstrates amylopectin (and not amylose) as the source of SHG in starch. According to our knowledge, this is the first estimation of the amylopectin's pitch angle in starch using PSHG

  10. COMPUTATION OF FIELD STRUCTURE AND AERODYNAMIC CHARACTERISTICS OF DELTA WINGS AT HIGH ANGLES OF ATTACK

    Institute of Scientific and Technical Information of China (English)

    YANG Li-zhi; GAO Zheng-hong

    2005-01-01

    A numerical investigation of the structure of the vortical flowfield over delta wings at high angles of attack in longitudinal and with small sideslip angle is presented.Three-dimensional Navier-Stokes numerical simulations were carried out to predict the complex leeward-side flowfield characteristics that are dominated by the effect of the breakdown of the leading-edge vortices. The methods that analyze the flowfield structure quantitatively were given by using flowfield data from the computational results. In the region before the vortex breakdown, the vortex axes are approximated as being straight line. As the angle of attack increases, the vortex axes are closer to the root chord, and farther away from the wing surface. Along the vortex axes, as the adverse pressure gradients occur, the axial velocity decreases, that is, λ is negative, so the vortex is unstable, and it is possible to breakdown. The occurrence of the breakdown results in the instability of lateral motion for a delta wing, and the lateral moment diverges after a small perturbation occurs at high angles of attack. However,after a critical angle of attack is reached, the vortices breakdown completely at the wing apex, and the instability resulting from the vortex breakdown disappears.

  11. REVIEW OF ADVANCES IN COBB ANGLE CALCULATION AND IMAGE-BASED MODELLING TECHNIQUES FOR SPINAL DEFORMITIES

    Directory of Open Access Journals (Sweden)

    V. Giannoglou

    2016-06-01

    Full Text Available Scoliosis is a 3D deformity of the human spinal column that is caused from the bending of the latter, causing pain, aesthetic and respiratory problems. This internal deformation is reflected in the outer shape of the human back. The golden standard for diagnosis and monitoring of scoliosis is the Cobb angle, which refers to the internal curvature of the trunk. This work is the first part of a post-doctoral research, presenting the most important researches that have been done in the field of scoliosis, concerning its digital visualisation, in order to provide a more precise and robust identification and monitoring of scoliosis. The research is divided in four fields, namely, the X-ray processing, the automatic Cobb angle(s calculation, the 3D modelling of the spine that provides a more accurate representation of the trunk and the reduction of X-ray radiation exposure throughout the monitoring of scoliosis. Despite the fact that many researchers have been working on the field for the last decade at least, there is no reliable and universal tool to automatically calculate the Cobb angle(s and successfully perform proper 3D modelling of the spinal column that would assist a more accurate detection and monitoring of scoliosis.

  12. Flow angle dependent photoacoustic Doppler power spectra under intensity-modulated continuous wave laser excitation

    Directory of Open Access Journals (Sweden)

    Yu Tong

    2016-02-01

    Full Text Available Photoacoustic Doppler (PAD power spectra showing an evident Doppler shift represent the major characteristics of the continuous wave-excited or burst wave-excited versions of PAD flow measurements. In this paper, the flow angle dependences of the PAD power spectra are investigated using an experiment setup that was established based on intensity-modulated continuous wave laser excitation. The setup has an overall configuration that is similar to a previously reported configuration, but is more sophisticated in that it accurately aligns the laser illumination with the ultrasound detection process, and in that it picks up the correct sample position. In the analysis of the power spectra data, we find that the background power spectra can be extracted by combining the output signals from the two channels of the lock-in amplifier, which is very useful for identification of the PAD power spectra. The power spectra are presented and analyzed in opposite flow directions, at different flow speeds, and at different flow angles. The power spectra at a 90° flow angle show the unique properties of symmetrical shapes due to PAD broadening. For the other flow angles, the smoothed power spectra clearly show a flow angle cosine relationship.

  13. Seismic behavior of outrigger truss-wall shear connections using multiple steel angles

    Science.gov (United States)

    Li, Xian; Wang, Wei; Lü, Henglin; Zhang, Guangchang

    2016-06-01

    An experimental investigation on the seismic behavior of a type of outrigger truss-reinforced concrete wall shear connection using multiple steel angles is presented. Six large-scale shear connection models, which involved a portion of reinforced concrete wall and a shear tab welded onto a steel endplate with three steel angles, were constructed and tested under combined actions of cyclic axial load and eccentric shear. The effects of embedment lengths of steel angles, wall boundary elements, types of anchor plates, and thicknesses of endplates were investigated. The test results indicate that properly detailed connections exhibit desirable seismic behavior and fail due to the ductile fracture of steel angles. Wall boundary elements provide beneficial confinement to the concrete surrounding steel angles and thus increase the strength and stiffness of connections. Connections using whole anchor plates are prone to suffer concrete pry-out failure while connections with thin endplates have a relatively low strength and fail due to large inelastic deformations of the endplates. The current design equations proposed by Chinese Standard 04G362 and Code GB50011 significantly underestimate the capacities of the connection models. A revised design method to account for the influence of previously mentioned test parameters was developed.

  14. Comparison of Debrecen and Mount Wilson/Kodaikanal sunspot group tilt angles and the Joy's law

    CERN Document Server

    Baranyi, T

    2014-01-01

    The study of active region tilt angles and their variations in different time scales plays an important role in revealing the subsurface dynamics of magnetic flux ropes and in understanding the dynamo mechanism. In order to reveal the exact characteristics of tilt angles, precise long-term tilt angle data bases are needed. However, there are only a few different data sets at present, which are difficult to be compared and cross-calibrate because of their substantial deviations. In this paper, we describe new tilt angle data bases derived from the Debrecen Photoheliographic Data ($DPD$) (1974--) and from the SOHO/MDI-Debrecen Data ($SDD$) (1996-2010) sunspot catalogues. We compare them with the traditional sunspot group tilt angle data bases of Mount Wilson Observatory (1917-85) and Kodaikanal Solar Observatory (1906-87) and we analyse the deviations. Various methods and filters are investigated which may improve the sample of data and may help deriving better results based on combined data. As a demonstration...

  15. Development of a software package for solid-angle calculations using the Monte Carlo method

    Science.gov (United States)

    Zhang, Jie; Chen, Xiulian; Zhang, Changsheng; Li, Gang; Xu, Jiayun; Sun, Guangai

    2014-02-01

    Solid-angle calculations play an important role in the absolute calibration of radioactivity measurement systems and in the determination of the activity of radioactive sources, which are often complicated. In the present paper, a software package is developed to provide a convenient tool for solid-angle calculations in nuclear physics. The proposed software calculates solid angles using the Monte Carlo method, in which a new type of variance reduction technique was integrated. The package, developed under the environment of Microsoft Foundation Classes (MFC) in Microsoft Visual C++, has a graphical user interface, in which, the visualization function is integrated in conjunction with OpenGL. One advantage of the proposed software package is that it can calculate the solid angle subtended by a detector with different geometric shapes (e.g., cylinder, square prism, regular triangular prism or regular hexagonal prism) to a point, circular or cylindrical source without any difficulty. The results obtained from the proposed software package were compared with those obtained from previous studies and calculated using Geant4. It shows that the proposed software package can produce accurate solid-angle values with a greater computation speed than Geant4.

  16. Performance and internal flow characteristics of a cross-flow turbine by guide vane angle

    International Nuclear Information System (INIS)

    This study attempts to investigate the performance and internal flow characteristics of a cross-flow turbine by guide vane angle. In order to improve the performance of a cross flow turbine, the paper presents a numerical investigation of the turbine with air supply and discusses the influence of variable guide vane angle on the internal flow. A newly developed air supply from air suction Hole is adopted. To investigate the performance and internal flow of the cross-flow turbine, the CFD software based on the two-phase flow model is utilized. The numerical grids are made in two-dimensional geometry in order to shorten the time of two-phase calculations. Then a series of CFD analysis has been conducted in the range of different guide vane angle. Moreover, local output power is divided at different stages and the effect of air layer in each stage is examined

  17. Preservation of roasted and ground coffee during storage Part 1: Moisture content and repose angle

    Directory of Open Access Journals (Sweden)

    Paulo C. Corrêa

    2016-06-01

    Full Text Available ABSTRACT The present study evaluates the influence of the level of roasting and the grind size on the moisture content and repose angle of coffee during storage. Raw coffee beans (Coffea canephora and Coffea arabica, hulled and dried, were roasted to two different levels: medium light (SCAA#65 and moderately dark (SCAA#45. The beans were then ground into three different grind sizes: fine (0.59 mm, medium (0.84 mm and coarse (1.19 mm. An additional coffee lot was kept whole. Following grinding, samples were stored at two different temperatures (10 and 30 ºC and analyzed after five different storage durations (0, 30, 60, 120 and 180 days. The moderately dark roast was found to have a lower moisture content. Finely ground samples had higher angles of repose. It is concluded that the grind size, level of roasting and duration of storage significantly affect the moisture content and angle of repose of coffee.

  18. A mesoscopic model for microscale hydrodynamics and interfacial phenomena: Slip, films, and contact angle hysteresis

    CERN Document Server

    Colosqui, Carlos E; Papathanasiou, Athanasios G; Kevrekidis, Ioannis G

    2012-01-01

    We present a model based on the lattice Boltzmann equation that is suitable for the simulation of dynamic wetting. The model is capable of exhibiting fundamental interfacial phenomena such as weak adsorption of fluid on the solid substrate and the presence of a thin surface film within which a disjoining pressure acts. Dynamics in this surface film, tightly coupled with hydrodynamics in the fluid bulk, determine macroscopic properties of primary interest: the hydrodynamic slip; the equilibrium contact angle; and the static and dynamic hysteresis of the contact angles. The pseudo- potentials employed for fluid-solid interactions are composed of a repulsive core and an attractive tail that can be independently adjusted. This enables effective modification of the functional form of the disjoining pressure so that one can vary the static and dynamic hysteresis on surfaces that exhibit the same equilibrium contact angle. The modeled solid-fluid interface is diffuse, represented by a wall probability function which...

  19. Storm-Time Evolution of Energetic Electron Pitch Angle Distributions by Wave-Particle Interaction

    Institute of Scientific and Technical Information of China (English)

    XIAO Fuliang; HE Huiyong; ZHOU Qinghua; WU Guanhong; SHI Xianghua

    2008-01-01

    The quasi-pure pitch-angle scattering of energetic electrons driven by field-alignedpropagating whistler mode waves during the 9~15 October 1990 magnetic storm at L ≈ 3 ~ 4 is studied, and numerical calculations for energetic electrons in gyroresonance with a band of frequency of whistler mode waves distributed over a standard Gaussian spectrum is performed. It is found that the whistler.mode waves can efficiently drive energetic electrons from the larger pitch-angles into the loss cone, and lead to a flat-top distribution during the main phase of geomagnetic storms. This result perhaps presents a feasible interpretation for observation of time evolution of the quasi-isotropic pitch-angle distribution by Combined Release and Radiation Effects Satellite (CRRES) spacecraft at L ≈ 3 ~ 4.

  20. Self-consistent inclusion of classical large-angle Coulomb collisions in plasma Monte Carlo simulations

    Energy Technology Data Exchange (ETDEWEB)

    Turrell, A.E., E-mail: a.turrell09@imperial.ac.uk; Sherlock, M.; Rose, S.J.

    2015-10-15

    Large-angle Coulomb collisions allow for the exchange of a significant proportion of the energy of a particle in a single collision, but are not included in models of plasmas based on fluids, the Vlasov–Fokker–Planck equation, or currently available plasma Monte Carlo techniques. Their unique effects include the creation of fast ‘knock-on’ ions, which may be more likely to undergo certain reactions, and distortions to ion distribution functions relative to what is predicted by small-angle collision only theories. We present a computational method which uses Monte Carlo techniques to include the effects of large-angle Coulomb collisions in plasmas and which self-consistently evolves distribution functions according to the creation of knock-on ions of any generation. The method is used to demonstrate ion distribution function distortions in an inertial confinement fusion (ICF) relevant scenario of the slowing of fusion products.

  1. Periods and Energy Dissipations of a Novel TLD Rectangular Tank with Angle-adjustable Baffles

    Institute of Scientific and Technical Information of China (English)

    SHANG Chun-yu; ZHAO Jin-cheng

    2008-01-01

    A novel tuned liquid damper (TLD) rectangular tank with two angle-adjustable baffles was presented. The numerical analysis was performed using the commercial code FLUENT. The standard kinetic energy and dissipation rate turbulent model was employed, which was solved using volume of fluid (VOF) method able to treat both the free surface motion and the viscous stresses over the rigid walls accurately. The relationship between the natural periods of water and the angles of its baffles was studied by numerical sim- ulating of a case, and the changes of energy dissipations were investigated. The natural periods and dampers of the novel TLD can be changed in a wide range by adjusting the baffles' angle, thus it is more effective in controlling the vibration of structures in a wide frequency range.

  2. Limited Angle Torque Motors Having High Torque Density, Used in Accurate Drive Systems

    Directory of Open Access Journals (Sweden)

    R. Obreja

    2011-01-01

    Full Text Available A torque motor is a special electric motor that is able to develop the highest possible torque in a certain volume. A torque motor usually has a pancake configuration, and is directly jointed to a drive system (without a gear box. A limited angle torque motor is a torque motor that has no rotary electromagnetic field — in certain papers it is referred to as a linear electromagnet. The main intention of the authors for this paper is to present a means for analyzing and designing a limited angle torque motor only through the finite element method. Users nowadays require very high-performance limited angle torque motors with high density torque. It is therefore necessary to develop the highest possible torque in a relatively small volume. A way to design such motors is by using numerical methods based on the finite element method.

  3. Polarization measurements analysis II. Best estimators of polarization fraction and angle

    CERN Document Server

    Montier, L; Levrier, F; Tristram, M; Alina, D; Ristorcelli, I; Bernard, J -P; Guillet, V

    2014-01-01

    With the forthcoming release of high precision polarization measurements, such as from the Planck satellite, it becomes critical to evaluate the performance of estimators for the polarization fraction and angle. These two physical quantities suffer from a well-known bias in the presence of measurement noise, as has been described in part I of this series. In this paper, part II of the series, we explore the extent to which various estimators may correct the bias. Traditional frequentist estimators of the polarization fraction are compared with two recent estimators: one inspired by a Bayesian analysis and a second following an asymptotic method. We investigate the sensitivity of these estimators to the asymmetry of the covariance matrix which may vary over large datasets. We present for the first time a comparison among polarization angle estimators, and evaluate the statistical bias on the angle that appears when the covariance matrix exhibits effective ellipticity. We also address the question of the accura...

  4. Polarization measurements analysis I. Impact of the full covariance matrix on polarization fraction and angle measurements

    CERN Document Server

    Montier, L; Levrier, F; Tristram, M; Alina, D; Ristorcelli, I; Bernard, J -P

    2014-01-01

    With the forthcoming release of high precision polarization measurements, such as from the Planck satellite, the metrology of polarization needs to improve. In particular, it is crucial to take into account full knowledge of the noise properties when estimating polarization fraction and angle, which suffer from well-known biases. While strong simplifying assumptions have usually been made in polarization analysis, we present a method for including the full covariance matrix of the Stokes parameters in estimates for the distributions of the polarization fraction and angle. We thereby quantify the impact of the noise properties on the biases in the observational quantities. We derive analytical expressions for the pdf of these quantities, taking into account the full complexity of the covariance matrix, including the Stokes I intensity components. We perform simulations to explore the impact of the noise properties on the statistical variance and bias of the polarization fraction and angle. We show that for low...

  5. Effect of Corrugation Angle on Heat Transfer Studies of Viscous Fluids in Corrugated Plate Heat Exchangers

    Directory of Open Access Journals (Sweden)

    B Sreedhara Rao

    2015-04-01

    Full Text Available In the present investigation heat transfer studies are conducted in corrugated plate heat exchangers (PHEs having three different corrugation angles of 300, 400 and 500. The plate heat exchangers have a length of 30 cm and a width of 10 cm with a spacing of 5 mm. Water and 20% glycerol solution are taken as test fluids and hot fluid is considered as heating medium. The wall temperatures are measured along the length of exchanger at seven different locations by means of thermocouples. The inlet and outlet temperatures of test fluid and hot fluid are measured by means of four more thermocouples. The experiments are conducted at a flowrate ranging from 0.5 lpm to 6 lpm with the test fluid. Film heat transfer coefficient and Nusselt number are determined from the experimental data. These values are compared with different corrugation angles. The effects of corrugation angles on heat transfer rates are discussed.

  6. Polarization of asteroid (387) Aquitania: the newest member of a class of large inversion angle asteroids

    CERN Document Server

    Masiero, Joseph

    2008-01-01

    We present new imaging polarimetric observations of two Main Belt asteroids, (234) Barbara and (387) Aquitania, taken in the first half of 2008 using the Dual-Beam Imaging Polarimeter on the University of Hawaii 2.2 meter telescope, located on Mauna Kea, Hawaii. Barbara had been previously shown to exhibit a very unusual polarization-phase curve by Cellino, et al. (2006). Our observations confirm this result and add Aquitania to the growing class of large inversion angle objects. Interestingly, these asteroids show spinel features in their IR spectra suggesting a mineralogical origin to the phase angle-dependent polarimetric features. As spinel is associated with calcium-aluminum-rich inclusions and carbonaceous chondrites, these large inversion angle asteroids may represent some of the oldest surfaces in the solar system. Circular as well as linear polarization measurements were obtained but circular polarization was not detected.

  7. Line tension and reduction of apparent contact angle associated with electric double layers

    CERN Document Server

    Dörr, Aaron

    2014-01-01

    The line tension of an electrolyte wetting a non-polar substrate is computed analytically and numerically. The results show that, depending on the value of the apparent contact angle, positive or negative line tension values may be obtained. Furthermore, a significant difference between Young's contact angle and the apparent contact angle measured several Debye lengths remote from the three-phase contact line occurs. When applying the results to water wetting highly charged surfaces, line tension values of the same order of magnitude as found in recent experiments can be achieved. Therefore, the theory presented may contribute to the understanding of line tension measurements and points to the importance of the electrostatic line tension. Being strongly dependent on the interfacial charge density, electrostatic line tension is found to be tunable via the pH value of the involved electrolyte. As a practical consequence, the stability of nanoparticles adsorbed at fluid-fluid interfaces is predicted to be depend...

  8. Tracing magnetic separators and their dependence on IMF clock angle in global magnetospheric simulations

    CERN Document Server

    Komar, C M; Dorelli, J C; Glocer, A; Kuznetsova, M M

    2013-01-01

    A new, efficient, and highly accurate method for tracing magnetic separators in global magnetospheric simulations with arbitrary clock angle is presented. The technique is to begin at a magnetic null and iteratively march along the separator by finding where four magnetic topologies meet on a spherical surface. The technique is verified using exact solutions for separators resulting from an analytic magnetic field model that superposes dipolar and uniform magnetic fields. Global resistive magnetohydrodynamic simulations are performed using the three-dimensional BATS-R-US code with a uniform resistivity, in eight distinct simulations with interplanetary magnetic field (IMF) clock angles ranging from 0 (parallel) to 180 degrees (anti-parallel). Magnetic nulls and separators are found in the simulations, and it is shown that separators traced here are accurate for any clock angle, unlike the last closed field line on the Sun-Earth line that fails for southward IMF. Trends in magnetic null locations and the struc...

  9. Time and angle resolved photoemission spectroscopy using femtosecond visible and high-harmonic light

    Energy Technology Data Exchange (ETDEWEB)

    Mathias, S; Deicke, F; Ruffing, A; Aeschlimann, M [Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern (Germany); Wiesenmayer, M; Bauer, M [Institut fuer experimentelle und angewandte Physik, Christian-Albrechts Universitaet zu Kiel, 24118 Kiel (Germany); Miaja-Avila, L; Murnane, M M; Kapteyn, H C, E-mail: SMathias@gmx.d [JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, Colorado 80309-0440 (United States)

    2009-02-01

    The angle resolved photoelectron spectroscopy (ARPES) has emerged as a leading technique in identifying static key properties of complex systems such as the electronic band structure of adsorbed molecules, ultrathin quantum-well films or high temperature superconductors. We efficiently combined ARPES by using a two-dimensional analyzer for parallel energy (E) and momentum (k{sub ||}) detection with femtosecond time-resolved spectroscopies. Using time and angle resolved two photon photoemission (2PPE) with visible light pulses, the hot electron dynamics in complex electronic structures are directly accessible by means of angle resolved hot electron lifetime mapping. Furthermore, femtosecond ARPES spectra recorded with high harmonic generation (HHG) light pulses are presented, showing the potential of this technique for future investigations of surface dynamics and photo-induced phase transition processes.

  10. Numerical Simulation of Airliner Cabin Environment based on Various Inlet Angles

    Directory of Open Access Journals (Sweden)

    Zhuo Huan Hu

    2014-07-01

    Full Text Available The study of airflow transport in airliner cabins is extremely important in creating a comfortable environment. The air temperature field and velocity field in the airliner cabin have significant influence on the health of pilots and passengers. In this study, heat transfer based on numerical study was carried out to investigate the effects of natural convection and air distribution with different angles. The average Reynolds equation and low Reynolds number turbulence model were used to simulate the airflow in the cabin. The convective term of convection diffusion equation was implemented with higher-order accurate schemes. Mathematical statistics was adopted to process the final data. Results showed that the effect of the natural convection could be negligible. Additional studies presented that air temperature field and flow field were largely affected by various inlet angles. A set of optimum matching inlet vane angles that could create a comfortable environment was determined.

  11. A laser speckle sensor to measure the distribution of static torsion angles of twisted targets

    DEFF Research Database (Denmark)

    Rose, B.; Imam, H.; Hanson, Steen Grüner;

    1998-01-01

    A novel method for measuring the distribution of static torsion angles of twisted targets is presented. The method is based on Fourier transforming the scattered field in the direction perpendicular to the twist axis, while performing an imaging operation in the direction parallel to the axis....... A cylindrical lens serves to image the closely spaced lateral positions of the target along the twist axis onto corresponding lines of the two dimensional image sensor. Thus, every single line of the image sensor measures the torsion angle of the corresponding surface position along the twist axis of the target....... Experimentally, we measure the distribution of torsion angles in both uniform and non-uniform deformation zones. It is demonstrated both theoretically and experimentally that the measurements are insensitive to object shape and target distance if the image sensor is placed in the Fourier plane. A straightforward...

  12. Angle dependence of Andreev scattering at semiconductor-superconductor interfaces

    DEFF Research Database (Denmark)

    Mortensen, Asger; Flensberg, Karsten; Jauho, Antti-Pekka

    1999-01-01

    and increase of the probability of normal reflection. We show that in the presence of a Fermi velocity mismatch between the semiconductor and the superconductor the angles of incidence and transmission are related according to the well-known Snell's law in optics. As a consequence there is a critical angle...

  13. EVALUATION OF NECK SHAFT ANGLE OF FEMUR ON DRY BONES

    OpenAIRE

    Radha; Ravi Shankar; Naveen; Roopa

    2015-01-01

    BACKGROUND: Evaluation of the neck shaft angle of femur helps to understand clinical relevance in bio mechanics of the hip joint. It helps for the better treatment of different pathological conditions of hip and femur and also to design prosthesis. Femoral neck shaft angle is important to convey the information regarding the race to ...

  14. Low angle neutron data acquisition system for molecular biology

    International Nuclear Information System (INIS)

    The low angle spectrometer system utilizing a 2-dimensional position sensitive counter was designed to accommodate a variety of experiments in molecular biology requiring good low angle resolution. Biological structures requiring low angle analysis techniques fall into two groups: non-ordered systems (proteins or protein complexes in solution) and ordered systems with large spacings like muscle, collagen, and membranes. For structural investigations into such systems, data are ideally needed to a low scattering angle of 0.20 at 4.5 A or a minimum Q of 0.005 A-1 (Q = theta . 2π/lambda). Depending on the type of structure, data often extend to the high angle region, say 300. Apart from the low angle requirements, the spectrometer has to have good resolution to resolve diffraction peaks from samples with crystal spacings up to 1000 A or even larger. While it is desirable to build a spectrometer to such scattering conditions, given reactor conditions might not permit this and compromises have to be made between flux, resolution and lowest angle. The low angle spectrometer described here was designed to be used at the HFBR neutron beam pipe working at approximately 4.2 A or at the H4 satellite station working at 2.4 A

  15. A new uncertainty relation for angular momentum and angle

    International Nuclear Information System (INIS)

    An uncertainty relation of the form ΔL2ΔSo >=sup(h/2π)/sub(2) is derived for angular momentum and angle. The non-linear operator So measures angles and has a simple interpretation. Subject to very general conditions of rotational invariance the above relation is unique. Radial momentum is not quantized

  16. A Novel Monopulse Angle Estimation Method for Wideband LFM Radars

    Directory of Open Access Journals (Sweden)

    Yi-Xiong Zhang

    2016-06-01

    Full Text Available Traditional monopulse angle estimations are mainly based on phase comparison and amplitude comparison methods, which are commonly adopted in narrowband radars. In modern radar systems, wideband radars are becoming more and more important, while the angle estimation for wideband signals is little studied in previous works. As noise in wideband radars has larger bandwidth than narrowband radars, the challenge lies in the accumulation of energy from the high resolution range profile (HRRP of monopulse. In wideband radars, linear frequency modulated (LFM signals are frequently utilized. In this paper, we investigate the monopulse angle estimation problem for wideband LFM signals. To accumulate the energy of the received echo signals from different scatterers of a target, we propose utilizing a cross-correlation operation, which can achieve a good performance in low signal-to-noise ratio (SNR conditions. In the proposed algorithm, the problem of angle estimation is converted to estimating the frequency of the cross-correlation function (CCF. Experimental results demonstrate the similar performance of the proposed algorithm compared with the traditional amplitude comparison method. It means that the proposed method for angle estimation can be adopted. When adopting the proposed method, future radars may only need wideband signals for both tracking and imaging, which can greatly increase the data rate and strengthen the capability of anti-jamming. More importantly, the estimated angle will not become ambiguous under an arbitrary angle, which can significantly extend the estimated angle range in wideband radars.

  17. A Novel Monopulse Angle Estimation Method for Wideband LFM Radars.

    Science.gov (United States)

    Zhang, Yi-Xiong; Liu, Qi-Fan; Hong, Ru-Jia; Pan, Ping-Ping; Deng, Zhen-Miao

    2016-01-01

    Traditional monopulse angle estimations are mainly based on phase comparison and amplitude comparison methods, which are commonly adopted in narrowband radars. In modern radar systems, wideband radars are becoming more and more important, while the angle estimation for wideband signals is little studied in previous works. As noise in wideband radars has larger bandwidth than narrowband radars, the challenge lies in the accumulation of energy from the high resolution range profile (HRRP) of monopulse. In wideband radars, linear frequency modulated (LFM) signals are frequently utilized. In this paper, we investigate the monopulse angle estimation problem for wideband LFM signals. To accumulate the energy of the received echo signals from different scatterers of a target, we propose utilizing a cross-correlation operation, which can achieve a good performance in low signal-to-noise ratio (SNR) conditions. In the proposed algorithm, the problem of angle estimation is converted to estimating the frequency of the cross-correlation function (CCF). Experimental results demonstrate the similar performance of the proposed algorithm compared with the traditional amplitude comparison method. It means that the proposed method for angle estimation can be adopted. When adopting the proposed method, future radars may only need wideband signals for both tracking and imaging, which can greatly increase the data rate and strengthen the capability of anti-jamming. More importantly, the estimated angle will not become ambiguous under an arbitrary angle, which can significantly extend the estimated angle range in wideband radars. PMID:27271629

  18. Bite angle effects of diphosphines in carbonylation reactions

    NARCIS (Netherlands)

    P.W.N.M. van Leeuwen; Z. Freixa

    2008-01-01

    This chapter contains sections titled: * Introduction * Rhodium-Catalyzed Hydroformylation o Introduction o Steric Bite Angle Effect and Regioselectivity o Electronic Bite Angle Effect and Activity o Isotope Effects [24] * Platinum-Catalyzed Alkene Hydroformylation * Palladium-Catalyzed CO/Ethene Co

  19. Showers with large zenith angles observed in emulsion chambers

    Institute of Scientific and Technical Information of China (English)

    任敬儒; 陆穗苓; 解卫; 王承瑞; 何瑁; 张乃健

    1997-01-01

    Showers with large zenith angles are observed in emulsion chambers exposed at Mt.Kanbala.The intensity of high energy muons is given and the multicore showers with large zenith angles are found.It is indicated that a new phenomenon may exist in the high energy nuclear interactions of cosmic rays.

  20. Engineering sidewall angles of silica-on-silicon waveguides

    DEFF Research Database (Denmark)

    Haiyan, Ou

    2004-01-01

    Burned photoresist is used as etch mask when producing silica-onsilicon waveguides. The sidewall angle of the optical glass waveguides is engineered by varying photoresist thickness and etch selectivity. The principle for the formation of the angles is introduced and very promising experimental...

  1. The effective take-off angle in PHI Quantera systems

    NARCIS (Netherlands)

    Van der Marel, C.

    2010-01-01

    It is well known that for quantitative analysis of XPS results theeffective take-off angle of the electrons is an important parameter.In the report is shown that the effective take-off angle i n PHI Quantera systems deviates significanlty from the set value. This is NOT a consequence of inadequa

  2. Dynamic aspects of contact angle measurements on adsorbed protein layers

    NARCIS (Netherlands)

    Scheer, van der At; Smolders, Cees A.

    1978-01-01

    Contact angle measurements using drops of paraffin oil have been performed on polystyrene (PS) substrates, coated with human serum albumin (HSA) or human fibrinogen (HFb), immersed in buffer solution. The contact angle appeared to be time dependent. The final value for HSA-coated substrates was 50°

  3. 46 CFR 58.01-40 - Machinery, angles of inclination.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Machinery, angles of inclination. 58.01-40 Section 58.01... AUXILIARY MACHINERY AND RELATED SYSTEMS General Requirements § 58.01-40 Machinery, angles of inclination. (a) Propulsion machinery and all auxiliary machinery essential to the propulsion and safety of the vessel must...

  4. Heterotrophic Pregnancy- Rare Presentation

    Directory of Open Access Journals (Sweden)

    AB Chattopadhyay

    2013-06-01

    Full Text Available Heterotopic pregnancy, a potentially dangerous and life-threatening clinical associated with intrauterine (IU and extra uterine pregnancies at the same time. Incidence of such cases are rare but very often missed as the diagnosis being overlooked during examination of the pregnant women with risk factors for an ectopic pregnancy such as free fluid with or without an adnexal mass or acute abdominal pain and shock presentation. Hence a high degree of clinical evaluation is warranted examining the pregnant women. In Present paper we report a case with rare presentation as heterotopic pregnancy from emergency hospital of teaching hospital.

  5. New mixing angles in the left-right symmetric model

    Science.gov (United States)

    Kokado, Akira; Saito, Takesi

    2015-12-01

    In the left-right symmetric model neutral gauge fields are characterized by three mixing angles θ12,θ23,θ13 between three gauge fields Bμ,WLμ 3,WRμ 3, which produce mass eigenstates Aμ,Zμ,Zμ', when G =S U (2 )L×S U (2 )R×U (1 )B-L×D is spontaneously broken down until U (1 )em . We find a new mixing angle θ', which corresponds to the Weinberg angle θW in the standard model with the S U (2 )L×U (1 )Y gauge symmetry, from these mixing angles. It is then shown that any mixing angle θi j can be expressed by ɛ and θ', where ɛ =gL/gR is a ratio of running left-right gauge coupling strengths. We observe that light gauge bosons are described by θ' only, whereas heavy gauge bosons are described by two parameters ɛ and θ'.

  6. Poincare duality angles for Riemannian manifolds with boundary

    CERN Document Server

    Shonkwiler, Clayton

    2009-01-01

    On a compact Riemannian manifold with boundary, the absolute and relative cohomology groups appear as certain subspaces of harmonic forms. DeTurck and Gluck showed that these concrete realizations of the cohomology groups decompose into orthogonal subspaces corresponding to cohomology coming from the interior and boundary of the manifold. The principal angles between these interior subspaces are all acute and are called Poincare duality angles. This paper determines the Poincare duality angles of a collection of interesting manifolds with boundary derived from complex projective spaces and from Grassmannians, providing evidence that the Poincare duality angles measure, in some sense, how "close" a manifold is to being closed. This paper also elucidates a connection between the Poincare duality angles and the Dirichlet-to-Neumann operator for differential forms, which generalizes the classical Dirichlet-to-Neumann map arising in the problem of Electrical Impedance Tomography. Specifically, the Poincare duality...

  7. The effect of knee joint angle on torque control.

    Science.gov (United States)

    Sosnoff, Jacob J; Voudrie, Stefani J; Ebersole, Kyle T

    2010-01-01

    The purpose of the author's investigation was to examine the effect of knee joint angle on torque control of the quadriceps muscle group. In all, 12 healthy adults produced maximal voluntary contractions and submaximal torque (15, 30, and 45% MVC [maximal voluntary contraction]) at leg flexion angles of 15 degrees , 30 degrees , 60 degrees , and 90 degrees below the horizontal plane. As expected, MVC values changed with respect to joint angle with maximum torque output being greatest at 60 degrees and least at 15 degrees . During the submaximal tasks, participants appropriately scaled their torque output to the required targets. Absolute variability (i.e., standard deviation) of torque output was greatest at 60 degrees and 90 degrees knee flexion. However, relative variability as indexed by coefficient of variation (CV) decreased as joint angle increased, with the greatest CV occurring at 15 degrees . These results are congruent with the hypothesis that joint angle influences the control of torque.

  8. Stable divergence angles of a magnetic dipole spiral array

    Energy Technology Data Exchange (ETDEWEB)

    Fan, X.D.; Bursill, L.A.

    1996-03-01

    An analytical model is introduced for Douady and Couder`s [1992] experiment, where phyllotactic patterns appear as a dynamical result of the interaction between magnetic dipoles. The difference equation for the divergence angle (i.e. the angle between successive radial vectors) is obtained by solving the equations of motion with a second nearest neighbour (SNN) approximation. A one dimensional map analysis as well as a comprehensive analytical proof shows that the divergence angle always converges to a single attractor regardless of the initial conditions. This attractor is approximately the Fibonacci angle ({approx} 138 deg) within variations due to a growth factor {mu} of the pattern. The system is proved to be stable with the SNN approximation. Further analysis with a third nearest neighbour approximation (TNN) shows extra linearly stable attractors may appear around the Lucas angle at {approx} 99.5 deg. 7 refs., 5 figs.

  9. Worsening angle closure glaucoma and choroidal detachments subsequent to closure of a carotid cavernous fistula

    Directory of Open Access Journals (Sweden)

    Thinda Sumeer

    2012-07-01

    Full Text Available Abstract Background Carotid cavernous fistulas are abnormal communications between the cavernous sinus and the external or internal carotid arteries. Although rare, closure of carotid cavernous fistulas can lead to immediate ocular complications. To our knowledge, our case represents the first report of worsening angle closure glaucoma and choroidal detachments over an extended period of two months subsequent to closure of a carotid cavernous fistula. Case presentation A 70-year-old female with a history of primary angle closure glaucoma presented with 4 mm of proptosis, resistance to retropulsion, tortuous corkscrew blood vessels and an orbital bruit of the right eye. Diagnostic cerebral angiogram showed a small indirect Barrow type D right carotid cavernous fistula. Transarterial embolization was planned but repeat cerebral angiography prior to the procedure demonstrated spontaneous partial closure of the carotid cavernous fistula and the procedure was aborted. One month later, our patient was noted to have worsening vision and choroidal detachments of the right eye. She declined further testing and was thus started on self-administered manual carotid jugular compressions. One month later, she developed progressive worsening of her choroidal detachments and angle closure. She eventually opted for surgical intervention but repeat cerebral angiography showed significant thrombosis of the carotid cavernous fistula and no intervention was warranted. Examination two months later showed complete resolution of the choroidal detachments and open angles of both eyes. Conclusions Our patient demonstrated worsening angle closure glaucoma and choroidal detachments after spontaneous closure of her carotid cavernous fistula had been noted. Ocular complications, including acute angle closure, have been reported to occur immediately after closure of carotid cavernous fistulas, but not over months as in our patient. It is imperative that individuals who have

  10. Practically Perfect Presentations.

    Science.gov (United States)

    Harris, Richard M.

    1994-01-01

    Offers nine practical suggestions for instructional presentations: build a sense of partnership, ask rhetorical questions, be spontaneous, use a conversational tone, control tone of voice, involve listener through gesture, be creative, be relevant, and achieve clarity. (JOW)

  11. Fostering oral presentation performance

    NARCIS (Netherlands)

    Ginkel, van Stan; Gulikers, Judith; Biemans, Harm; Mulder, Martin

    2016-01-01

    Previous research revealed significant differences in the effectiveness of various feedback sources for encouraging students’ oral presentation performance. While former studies emphasised the superiority of teacher feedback, it remains unclear whether the quality of feedback actually differs bet

  12. Doctoral Research Presentations

    OpenAIRE

    Thomson, Alison; Plummer-Fernandez, Matthew; Yurman, Paulina; Migliore, Enza; Gray, Nicola; Yang, Ya-huei; Hogan, Nicola; Kerridge, Tobie

    2015-01-01

    The Department of Design has a thriving community of scholars and practitioners engaged in doctoral research. In this session students,graduates and visiting researchers will present their research covering a broad range of topics and research interests.

  13. Workshop Presentations: BSCW Analysts

    Data.gov (United States)

    National Aeronautics and Space Administration — These slides were presented at the AePW, April 21-22, 2012. They detail the analytical results generated by each of the participating analysis teams for the...

  14. Workshop Presentations: RSW Analysts

    Data.gov (United States)

    National Aeronautics and Space Administration — These slides were presented at the AePW, April 21-22, 2012. They detail the analytical results generated by each of the participating analysis teams for the...

  15. Workshop Presentations: HIRENASD Analysts

    Data.gov (United States)

    National Aeronautics and Space Administration — These slides were presented at the AePW, April 21-22, 2012. They detail the analytical results generated by each of the participating analysis teams for the HIRENASD.

  16. ARE YOU PRESENT?

    OpenAIRE

    Juul, Henrik; Gilmartin, Thomas; Thomas, Thomas Tom

    2007-01-01

    Master of Computer Mediated Comunication thesis: ARE YOU PRESENT? FROM SPECTATOR TO PARTICIPANT IN COMPUTER MEDIATED CONFERENCES This thesis analyzes the application of Social Presence theory on a conference with participants attending online in UNDP and the consequences hereof.

  17. A rare case of racemose neurocysticercosis of the posterior fossa.

    Science.gov (United States)

    Karegowda, Lakshmikanth Halegubbi; Shenoy, Poonam Mohan; Prakashini, Koteshwara; Karur, Gauri

    2014-05-26

    A 43-year-old man presented with a 3 month history of headache, vertigo and swaying while walking. MRI of the brain showed cystic lesions involving the cerebellopontine angle cisterns, the right perimedullary cistern, the fourth ventricle and bilateral foramen of Luschka with resultant obstruction to cerebrospinal fluid outflow and hydrocephalus. The patient underwent right retromastoid craniotomy with endoscopic third ventriculostomy for cyst excision. The postoperative period was uneventful and he was able to carry out routine activities within a month. This case report stresses on the clinical importance, unique characteristics and imaging features of racemose neurocysticercosis.

  18. Germinoma in the Internal Auditory Canal Mimicking a Vestibular Schwannoma

    Directory of Open Access Journals (Sweden)

    Rubén Martín-Hernández

    2014-01-01

    Full Text Available The appearance of a primary germinoma in the central nervous system but not on or near the midline or within the brain is exceptional. It may occur at any age; however, it is rare in patients over 50 years old. Only a handful of cases of germinomas located in the cerebellopontine angle were presented, but to our knowledge, there has been no description of an isolated germinoma in the internal auditory canal. We report a case of germinoma in the internal auditory canal in a 51-year-old man simulating the clinical and radiological characteristics of a vestibular schwannoma.

  19. Multiple Unilateral Vestibular Schwannomas: Segmental NF2 or Sporadic Occurrence?

    OpenAIRE

    Carlson, Matthew L.; Van Gompel, Jamie J.

    2016-01-01

    Objective To report a case of a patient presenting with two separate unilateral vestibular schwannomas (VSs) without other stigmata of neurofibromatosis type 2 (NF2). Study Design This article discusses a case report and review of the literature. Setting Tertiary academic referral center. Participants A 41-year-old female was referred for evaluation of a left-sided 1.8-cm cerebellopontine angle tumor centered on the porus acusticus and a separate ipsilateral 3-mm intracanalicular tumor appear...

  20. Anesthesia Dolorosa of Trigeminal Nerve, a Rare Complication of Acoustic Neuroma Surgery

    Directory of Open Access Journals (Sweden)

    Foad Elahi

    2014-01-01

    Full Text Available Anesthesia dolorosa is an uncommon deafferentation pain that can occur after traumatic or surgical injury to the trigeminal nerve. This creates spontaneous pain signals without nociceptive stimuli. Compression of the trigeminal nerve due to acoustic neuromas or other structures near the cerebellopontine angle (CPA can cause trigeminal neuralgia, but the occurrence of anesthesia dolorosa subsequent to acoustic tumor removal has not been described in the medical literature. We report two cases of acoustic neuroma surgery presented with anesthesia dolorosa along the trigeminal nerve distribution. The patients’ pain was managed with multidisciplinary approaches with moderate success.