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Sample records for cerebellopontine angle presenting

  1. 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.

  2. 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.

  3. Meningiomas of the cerebellopontine angle.

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    Matthies, C; Carvalho, G; Tatagiba, M; Lima, M; Samii, M

    1996-01-01

    Meningiomas of the cerebellopontine angle (CPA) represent a clinically and surgically interesting entity. The opportunity of complete surgical excision and the incidence of impairment of nerval structures largely depend on the tumour biology that either leads to displacement of surrounding structures by an expansive type of growth or to an enveloping of nerval and vascular structures by an en plaque type of growth. As the origin and the direction of growth are very variable, the exact tumour extension in relation to the nerval structures and the tumour origin can be identified sometimes only at the time of surgery. Out of a series of 230 meningiomas of the posterior skull base operated between 1978 and 1993, data of 134 meningiomas involving the cerebellopontine angle are presented. There were 20% male and 80% female patients, age at the time of surgery ranging from 18 to 76 years, on the average 51 years. The clinical presentation was characterized by a predominant disturbance of the cranial nerves V (19%), VII (11%), VIII (67%) and the caudal cranial nerves (6%) and signs of ataxia (28%). 80% of the meningiomas were larger than 30 mm in diameter, 53% led to evident brainstem compression or dislocation and 85% extended anteriorly to the internal auditory canal. Using the lateral suboccipital approach in the majority of cases and a combined presigmoidal or combined suboccipital and subtemporal approaches in either sequence in 5%, complete tumour removal (Simpson I and II) was accomplished in 95% and subtotal tumour removal in 5%. Histologically the meningiotheliomatous type was most common (49%) followed by the mixed type (19%), fibroblastic (16%), psammomatous (7%), hemangioblastic (7%) and anaplastic (2%) types. Major post-operative complications were CSF leakage (8%) requiring surgical revision in 2% and hemorrhage (3%) requiring revision in 2%. While the majority of neurological disturbances showed signs of recovery, facial nerve paresis or paralysis was

  4. Primary cerebello-pontine angle malignant melanoma : a case report.

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    Desai K

    2001-04-01

    Full Text Available A rare case of primary malignant melanoma in the cerebello-pontine angle, in a 17 year old girl is presented. The patient presented with one month history of headache, diplopia, facial asymmetry and ataxia. The computerised tomography (CT scan and magnetic resonance imaging (MRI revealed a large cerebello-pontine angle mass with features suggestive of a melanoma. The typical black coloured, solid and vascular melanoma was excised completely. Cerebello-pontine angle melanoma are extremely rare tumours with dismal long term outcome in majority of these cases.

  5. [Cerebellopontine angle meningeal melanocytoma: a benign tumor?].

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    González-Tortosa, J; Ferri-Níguez, B; Ros de San Pedro, J

    2009-08-01

    We report a case of a rare meningeal melanocytoma in the cerebellopontine angle. One year after tumor gross total removal, the patient suffered a sudden and devastating meningeal melanomatosis. The relevant literature is reviewed looking for the keys to establish preoperative diagnosis and to obtain information about its treatment and postsurgical management.

  6. Study of malignant peripheral nerve sheath tumor in cerebellopontine angle.

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    Hong, WenMing; Cheng, HongWei; Wang, XiaoJie; Hu, XiaoPeng; Feng, ChunGuo

    2014-01-01

    Malignant peripheral nerve sheath tumors (MPNSTs) are very rare soft tissue sarcomas, usually arising from somatic soft tissues or peripheral nerves. Primary MPNST of the cerebellopontine angle is extremely rare, with only a single case reported so far. Here, we report an unusual case of MPNST in cerebellopontine angle in a 25-year-old man presented with dizziness, left facial numbness, and tinnitus. After hospitalization, the tumor was treated with complete surgical excision followed by adjuvant chemotherapy and radiotherapy. Histologically, the tumor showed malignant spindle cells, which were with focal S-100 positivity on immunohistochemistry, and a diagnosis of the MPNST was made. This case is being reported for its rarity and presence in cerebellopontine and illustrated the difficulties in the diagnosis and treatment of MPNST, which to the best of our knowledge, has not been described before in the soft tissue sarcomas.

  7. Magnetic resonance imaging of cerebellopontine angle lesions

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    Pratiksha Yadav

    2015-01-01

    Full Text Available Background: Cerebellopontine angle (CPA tumors are usually benign, and they are divided into extra-axial, intra-axial, extradural, and petrous axis tumors. CPA pathologies can be asymptomatic or it may present with vertigo, tinnitus, or unilateral hearing loss depending upon the site of tumor origin and displacement of the neurovascular structure. Aim and Objectives: To evaluate the role of magnetic resonance imaging (MRI aided with contrast-enhanced MRI as an imaging modality for diagnosis of CPA lesions. Materials and Methods: Analysis of 36 patients of CPA lesions over a period of 2 years was done. MRI was performed on Siemens 1.5 Tesla MAGNETOM Avanto Machine. Conclusion: There are spectrums of pathologies, which can present with these symptoms, which includes tumors, vascular malformations, and vascular loop compressing vestibulocochlear nerve or mastoid pathology so it is important to investigate the patient by MRI. Contrast-enhanced MRI is the most sensitive investigation in the evaluation of the CPA lesions, its characteristic, and its extent.

  8. Cerebellopontine angle facial schwannoma relapsing towards middle cranial fossa

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    Takafumi Nishizaki

    2011-05-01

    Full Text Available Facial nerve schwannomas involving posterior and middle fossas are quite rare. Here, we report an unusual case of cerebellopontine angle facial schwannoma that involved the middle cranial fossa, two years after the first operation. A 53-year-old woman presented with a 3-year history of a progressive left side hearing loss and 6-month history of a left facial spasm and palsy. Magnetic resonance imaging (MRI revealed 4.5 cm diameter of left cerebellopontine angle and small middle fossa tumor. The tumor was subtotally removed via a suboccipital retrosigmoid approach. The tumor relapsed towards middle cranial fossa within a two-year period. By subtemporal approach with zygomatic arch osteotomy, the tumor was subtotally removed except that in the petrous bone involving the facial nerve. In both surgical procedures, intraoperative monitoring identified the facial nerve, resulting in preserved facial function. The tumor in the present case arose from broad segment of facial nerve encompassing cerebellopontine angle, meatus, geniculate/labyrinthine and possibly great petrosal nerve, in view of variable symptoms. Preservation of anatomic continuity of the facial nerve should be attempted, and the staged operation via retrosigmoid and middle fossa approaches using intraoperative facial monitoring, may result in preservation of the facial nerve.

  9. Rare lesions of the cerebellopontine angle.

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    Yilmaz, Cem; Altinors, Nur; Sonmez, Erkin; Gulsen, Salih; Caner, Hakan

    2010-07-01

    Vestibular schwannomas, meningiomas and epidermoids account for a vast majority of the lesions occurring in the cerebellopontine angle (CPA). Neoplastic and non-neoplastic pathologies other than these tumors constitute 1% of all lesions located in the CPA. The aim of this study was to reveal our experience in the treatment of the rare lesions of the CPA. We have retrospectively reviewed the medical files and radiological data of all patients who underwent surgery involving any kind of pathology in the CPA. We have excluded those patients with a histopathological diagnosis of meningioma, schwannoma and epidermoids. Our research revealed a case of craniopharyngioma, a case of chloroma, a case of solitary fibrous tumor, a case of pinealoblastoma, a case of atypical teratoid rhabdoid tumor, a case of an aneurysm, a case of hemorrhage and a case of abscess.

  10. 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.

  11. 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

  12. 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.

  13. Intratentorial lipomas with Meckel's cave and cerebellopontine angle extension.

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    Ruocco, M J; Robles, H A; Rao, K C; Armonda, R A; Ondra, S L

    1995-08-01

    An unusual case of bilateral intratentorial lipomas with extension into Meckel's caves and the cerebellopontine angle is described. Surgical and histopathologic correlation demonstrate that the lipoma encased the trigeminal nerve in Meckel's caves. The origin of the lipoma from the anteromedial margins of the tentorium is discussed and correlated with a recently proposed theory for the development of intracranial lipomas.

  14. Tumors of the cerebellopontine angle; Tumoren des Kleinhirnbrueckenwinkels

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    Schulze, Maximilian [Universitaetsklinikum Tuebingen (Germany). Abt. fuer Diagnostische und Interventionelle Neuroradiologie; Reimann, Katrin [Universitaetsklinikum Tuebingen (Germany). HNO Klinik; Soares Tatagiba, Marcos [Universitaetsklinikum Tuebingen (Germany). Klinik fuer Neurochirurgie; Bisdas, Sotirios [The National Hospital for Neurology and Neurosurgery, London (United Kingdom). Dept. of Neuroradiology

    2016-12-15

    The diagnostic imaging of lesions in the cerebellopontine angle is mainly challenged by the possible differential diagnoses and their therapeutic relevance. As classification of tumors in contrast-enhancing and non-enhancing allows for a primary differentiation, MRI holds pivotal role in diagnosis and therapy planning on the basis of its quantitative and qualitative methods as volumetry, diffusion weighted imaging, perfusion imaging and spectroscopy.

  15. Anatomy of the cerebellopontine angle; Anatomie des Kleinhirnbrueckenwinkels

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

    2006-03-15

    The cerebellopontine angle (CPA) is an anatomically complex region of the brain. In this article we describe the anatomy of the CPA cisterns, of the internal auditory canal, the topography of the cerebellum and brainstem, and the neurovascular structures of this area. (orig.) [German] Der Kleinhirnbrueckenwinkel ist eine umschriebene anatomische Region. Im diesem Artikel werden die Subarachnoidalraeume im Kleinhirnbrueckenwinkel, die Anatomie der Felsenbeinflaeche, Anatomie und Topographie des Kleinhirns und des Hirnstamms, die arteriellen Beziehungen und venoese Drainage des Kleinhirnbrueckenwinkels besprochen. (orig.)

  16. 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.

  17. Unusual magnetic resonance characteristics of a cerebellopontine angle epidermoid cyst with upper cervical spinal canal extension.

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    Teo, Beng-Tiong; Lin, Chao-chun; Chiou, Tsung-Lang; Chen, Shang-Chi; Yen, Pao-Sheng

    2006-08-01

    We present a 27-year-old woman with an epidermoid cyst at the cerebellopontine (CP) angle with caudal extension into the upper cervical spinal canal. The lesion showed unusual hyperintensity on T1-weighted images, and hypointensity on T2-weighted images. We used microneurosurgical techniques for tumour dissection and excision. To our knowledge, this is the fifth example in Index Medicus/MEDLINE of histopathologically proven CP angle epidermoid with cervical spine extension.

  18. Anatomic structural study of cerebellopontine angle via endoscope

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    XIA Yin; LI Xi-ping; HAN De-min; ZHENG Jun; LONG Hai-shan; SHI Jin-feng

    2007-01-01

    Background Minimally invasive surgery in skull base relying on searching for possible anatomic basis for endoscopic technology is controversial. The objective of this study was to observe the spatial relationships between main blood vessels and nerves in the cerebellopontine angle area and provide anatomic basis for lateral and posterior skull base minimally invasive surgery via endoscopic retrosigmoid keyhole approach.Methods This study was conducted on thirty dried adult skulls to measure the spatial relationships among the surface bony marks of posterior cranial fossa, and to locate the most appropriate drilling area for retrosigmoid keyhole approach.In addition, we used 10 formaldehyde-fixed adult cadaver specimens for simulating endoscopic retrosigmoid approach to determine the visible scope.Results The midpoint between the mastoid tip and the asterion was the best drilling point for retrosigmoid approach. A hole centered on this point with the 2.0 cm in diameter was suitable for exposing the related structures in the cerebellopontine angle. Retrosigmoid keyhole approach can decrease the pressure on the cerebellum and expose the related structures effectively which include facial nerve, vestibulocochlear nerve, trigeminal nerve, glossopharyngeal nerve, vagus nerve, accessory nerve, hypoglossal nerve, anterior inferior cerebellar artery, posterior inferior cerebellar artery and labyrinthine artery, etc.Conclusions Exact location on endoscope retrosigmoid approach can avoid dragging cerebellum during the minimally invasive surgery. The application of retrosigmoid keyhole approach will extend the application of endoscopic technology.

  19. 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)

  20. 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.)

  1. A Case of Bell's Palsy with an Incidental Finding of a Cerebellopontine Angle Lipoma.

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    Lagman, Carlito; Choy, Winward; Lee, Seung J; Chung, Lawrance K; Bui, Timothy T; Yang, Isaac; Goldman, Howard W

    2016-08-24

    This case report illustrates the potential fallacy of attributing a patient's symptoms to an incidental finding. Serial imaging of small, asymptomatic cerebellopontine angle (CPA) lipomas is favored. It is imperative to accurately diagnose CPA lipoma on imaging and differentiate it from more common CPA lesions. We herein present a patient with symptoms consistent with Bell's palsy and an incidental finding of a CPA lipoma. Additionally, we performed a review of the literature for case reports of patients presenting with facial symptoms and diagnosed with a CPA lipoma.

  2. 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.

  3. 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.

  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. Dural Arteriovenous Fistula Following Translabyrinthine Resection of Cerebellopontine Angle Tumors: Report of Two Cases

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    Li, Peter M.M.C.; Fischbein, Nancy J.; Do, Huy M.; Blevins, Nikolas H.

    2011-01-01

    We describe two cases of dural arteriovenous fistula (DAVF) developing in a delayed fashion after translabyrinthine resection of cerebellopontine angle tumors. Two patients in an academic tertiary referral center, a 46-year-old woman and a 67-year-old man, underwent translabyrinthine resection of a 2-cm left vestibular schwannoma and a 4-cm left petrous meningioma, respectively. Both patients subsequently developed DAVF, and in each case the diagnosis was delayed despite serial imaging follow-up. In one patient, cerebrospinal fluid diversion before DAVF was identified as the cause of her intracranial hypertension; the other patient was essentially asymptomatic but with a high risk of hemorrhage due to progression of cortical venous drainage. Endovascular treatment was effective but required multiple sessions due to residual or recurrent fistulas. Dural arteriovenous fistula is a rare complication of translabyrinthine skull base surgery. Diagnosis requires a high index of clinical suspicion and an understanding of subtle imaging findings that may be present on follow-up studies performed for tumor surveillance. Failure to recognize this complication may lead to misguided interventions for treatment of hydrocephalus and other complications, as well as ongoing risks related to venous hypertension and intracranial hemorrhage. As this condition is generally curable with neurointerventional and/or surgical methods, timely diagnosis and treatment are essential. PMID:23984203

  6. 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.

  7. Symptomatic ependymal cysts of the perimesencephalic and cerebello-pontine angle cisterns.

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    Sharma, R R; Pawar, S J; Kharangate, P P; Delmendo, A

    2000-11-01

    Primary intracranial ependymal cysts are extremely rare. These are congenital, benign ependyma lined, commonly intraparenchymal and uncommonly extraparenchymal cysts in leptomeningeal location of variable size seen in the adult life. The authors report two cases of symptomatic ependymal cysts: one in the perimesencephalic cistern in a 10-month-old infant presenting with delayed mile stones and another in the cerebello-pontine cistern in a morbidly obese 35-year-old woman with known benign intracranial hypertension now presenting with hemifacial spasm. Neurosurgical intervention was curative in both cases. Interesting clinical, radiological and histological features are presented and discussed.

  8. 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

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

    Science.gov (United States)

    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.

  10. 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.

  11. 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.)

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. A connection between neurovascular conflicts within the cerebellopontine angle and vestibular neuritis, a case controlled cohort study

    OpenAIRE

    Loader, B.; Linauer, I.; Korkesch, S.; Krammer-Effenberger, I.; Zielinski, V.; Schibany, N.; Kaider, A.; Vyskocil, E.; Tscholakoff, D.; Franz, P.

    2016-01-01

    SUMMARY This retrospective, observer blinded case-control study aims to compare the prevalence of neurovascular conflicts (NVCs) of the vestibulocochlear nerve and the anterior inferior cerebellar artery (AICA) in patients presenting with clinical signs of acute vestibular neuritis with and without subsequent objective vestibular function loss (VFL). 58 acute cases of clinically suspected acute vestibular neuritis were investigated with same day cranial MRI at a tertiary referral centre and c...

  18. Late metastasis of breast adenocarcinoma into internal auditory canal and cerebellopontine angle: case report Metástase tardia de adenocarcinoma de mama para o canal auditivo interno e ângulo ponto-cerebelar: relato de caso

    Directory of Open Access Journals (Sweden)

    Edilson Marques

    2002-09-01

    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.Um caso de metástase de adenocarcinoma de mama para o canal auditivo interno e ângulo ponto-cerebelar é apresentado. A metástase ocorreu após 16 anos do tumor primário ter sido tratado com cirurgia e radioterapia. A paciente de 66 anos foi considerada curada de sua doença primária, quando apresentou perda auditiva de progressão rápida associada a paralisia facial intermitente. Ressonância magnética demonstrou uma lesão expansiva intra e extracanalicular, cujo aspecto radiológico lembrava schwannoma do vestibular. A paciente foi submetida a cirurgia e investigação histopatológica confirmou tratar-se de metástase. Metástase é uma rara ocorrência dentro do canal auditivo interno e ângulo ponto-cerebelar. História clínica de paralisia facial severa aumentará a suspeita de lesão maligna apesar dos achados radiológicos.

  19. MRI对桥小脑角池占位病变的诊断价值分析%Analysis of Diagnostic Value of MRI for Occupied Lesions in Cerebellopontine Angle

    Institute of Scientific and Technical Information of China (English)

    蒋君军; 罗庆华

    2014-01-01

    Objective To investigate the radiological appearances and diagnostic value of MRI of occupied lesions in cerebellopon-tine angle, and to provide effective diagnostic basis for clinic. Methods 35 cases of patients with cerebellopontine angle proved surgically and pathologically in our hospital from January 2010 to May 2014 were selected, the preoperative MRI of these patients were retrospectively investigated. Results 15 cases were meningeoma, accounting for 43%;10 cases were acoustic neuroma, accounting for 29%;5 cases were epidermoid cyst, accounting for 14%;2 cases were arachroid cyst, 2 cases were dermoid cyst and 1 case was lipoma, which totally accounted for 14%. Conclusions As MRI can clearly reflect the shape, size and scope of the occupied lesions in cerebellopontine angle, we can make a qualitative diagnosis combining with MRI, thus to provide effective basis for clinical surgery.%目的:探讨桥小脑角池内占位病变的M砸陨影像学表现及诊断价值,为临床提供有效的诊断依据。方法收集我院2010年1月至2014年5月共35例经手术及病理证实桥小脑角池内占位病变,回顾分析患者术前的M砸陨检查图像。结果15例为脑膜瘤,占43豫;10例为听神经瘤,占29豫;5例为表皮样囊肿,占14豫;2例为蛛网膜囊肿,2例为皮样囊肿,1例为脂肪瘤,共占14豫。结论M砸陨影像可清楚地反映桥小脑角池占位病灶的形态、大小、范围等。结合M砸陨影像学表现可以做出定性诊断,为临床手术治疗提供有效的依据。

  20. Neuralgia do trigêmeo bilateral por cisticerco racemoso unilateral no ângulo-ponto cerebelar: relato de caso Unusual cause for bilateral trigeminal neuralgia: unilateral racemous cysticercus of cerebellopontine angle. Case report

    Directory of Open Access Journals (Sweden)

    PAULO HENRIQUE AGUIAR

    2000-12-01

    Full Text Available Descrevemos o caso de uma paciente de 42 anos portadora de cisticerco racemoso na região do ângulo ponto-cerebelar (APC direito com trigeminalgia bilateral mais intensa no lado ipsilateral à localização do parasita. O cisticerco foi totalmente removido por meio de craniotomia suboccipital. No primeiro dia pós-operatório houve desaparecimento bilateral da dor. Duas hipóteses fisiopatológicas foram aventadas para explicar a sintomatologia: lesões que ultrapassam os limites da cisterna do APC poderão através da cisterna pré-pontina alcançar a cisterna do APC atingindo o trigêmeo contralateral; lesões com grande efeito de massa poderão provocar rotação do tronco cerebral e deslocamento e tração de estruturas ipsi e contralaterais, provocando compressão arteriovenosa sobre o trigêmeo contralateral na porção superior da cisterna do APC. Salientamos a necessidade de exames de imagem ante qualquer algia craniofacial e observamos que, em lesões na região do APC, a cisticercose não pode ser esquecida.We report the case of a 42-year-old woman with a racemous cystecercus in the right cerebellopontine angle (CPA, who presented with bilateral trigeminal neuralgia. The parasite was completly removed via a right suboccipital craniotomy. On the first postoperative day, the patient indicated that the pain disappeared. The neuralgia was caused by two probable mechanisms: a distortion of the brain stem and compression of the nerve against an arterial loop at the entry zone or arachnoiditis caused by the parasite in the both CPA cisternae. This case demonstrates the advisability of obtaining imaging studies in all patients with trigeminal neuralgia before starting any management. We must always remind that the cysticercus may be a differential diagnosis of CPA lesions.

  1. Clinicopathologic features of endolymphatic sac tumor at cerebellopontine angle%桥脑小脑角区内淋巴囊肿瘤五例临床病理分析及鉴别诊断

    Institute of Scientific and Technical Information of China (English)

    杜江; 王军梅; 崔云; 李桂林

    2011-01-01

    ObjectiveTo study the clinicopathologic features and immunophenotype of endolymphatic sac tumor (ELST) and normal endolymphatic sac. Methods The clinical and histologic features were evaluated in 5 cases of ELST. Eight cases of choroid plexus papilloma at cerebellopontine angle and 2 cases of normal endolymphatic sac were used as controls. Immunohistochemical study for vimentin,AE1/AE3, CK8/18, CK5/6, EMA, GFAP, synaptophysin, S-100 protein, CEA, TTF-1, VEGF, D2-40,calponin, calretinin and Ki-67 was carried out. Results The age of onset of ELST ranged from 23 to 35years ( median =24 years ). The male-to-female ratio was 2 ∶ 3. The clinical presentation was tinnitus,otalgia, hearing loss, otorrhagia with effusion and headache. The duration of symptoms ranged from 6 months to 10 years. Local recurrences were noted in 3 cases. Radiologically, the tumors were located at cerebellopontine angle and demonstrated petrous bone destruction. Histologic examination showed that the tumors had a papillary-glandular pattern. The papillae were covered by a single layer of low cuboidal cells. The tumor cells had distinct cell borders and contained eosinophilic to clear cytoplasm. The nuclei were slightly atypical and sometimes apically located. Focal dilated glandular structures with colloid-like material were also identified. The surrounding stroma was vascularized. All of the 5 cases had dural or petrous bone infiltration. Immunohistochemical study showed that all of the 5 cases were positive for AE1/AE3, CK8/18,CK5/6 and VEGF, 4 cases for EMA, 3 cases for calponin (focal) , 2 cases for vimentin, 2 cases for S-100protein, 1 case for GFAP and 1 case for synaptophysin (focal and weak). The Ki-67 index measured less than 1%. The staining for D2-40, calretinin, CEA and TTF-1 was negative. The 2 cases of the normal endolymphatic sac were positive for AE1/AE3 and CK8/18, and negative for CK5/6, EMA, S-100 protein,GFAP and synaptophysin. The 8 cases of choroid plexus papilloma were

  2. pc-ASL 技术在桥小脑角区肿瘤术后复发评估%The diagnostic value of PCASL MRI technique in evaluating post-operative recurrence of cerebellopontine angle tumor

    Institute of Scientific and Technical Information of China (English)

    石凤祥; 王玉凤; 王海辉; 徐田勇; 荣凡令

    2015-01-01

    目的:探讨3D FSE 的 pc-ASL 技术对桥小脑角区肿瘤术后复发的诊断价值。方法:选取21例桥小脑角区占位性病变术后患者,行常规平扫及增强序列,在增强前扫描 pc-ASL 序列。将 pc-ASL 功能图像与增强后 Ax 3D T1 WI 融合,测量异常强化区域及对侧正常脑组织的 CBF 值,评价是否存在肿瘤复发。结果:全部21例手术区出现异常强化区患者,13例为复发。17例患者行 DSC-PWI 失败,图像无法满足诊断需求。全部21例 pc-ASL 检查成功。肿瘤复发区域的CBF 值为(64.2±3.03)mL/100g/min,对侧正常脑实质的 CBF 值为(52.5±1.89)mL/100g/min。肿瘤复发区域的 CBF值明显高于对照侧脑组织,两者之间差异有统计学意义(t=12.498,P <0.05)。结论:基于3D FSE 的 pc-ASL 序列安全无创,无需注射对比剂,磁敏感效应影响小,可以用于评估桥小脑角区肿瘤有无术后复发。%Objective:The purpose of this study was to assess the diagnostic value of 3D FSE pseudo-continuous arte-rial spin labeling (pCASL)technique in evaluating post-operative recurrence of cerebellopontine angle tumor.Methods:21 post-operative patients with cerebellopontine angle tumor underwent pre-and post-contrast MRI scans.Perfusion-weighted MR imaging (PWI)with pCASL technique was performed before contrast injection.The CBF maps generated from pCASL were fused with post-contrast 3D T1 WI.The CBF values of abnormal enhanced area and contralateral normal brain tissue were measured and statistically analyzed to assess whether there was a recurrence of the neoplasm.Results:The neoplasm recurrence was found in 13/21 cases.DSC-PWI failed to generate functional maps in 17/21 cases due to the susceptibility ar-tifact;however,all 21 cases successfully underwent pCASL scan using 3D-FSE sequence.The mean CBF values were (64.2 ±3.03)mL/100g/min for the recurrent neoplasm and (52.5 ±1.89)mL/100g/min for

  3. 小脑脑桥角海绵状血管畸形三例并文献复习%Cystic cavernous malformations in the cerebellopontine angle: report of three cases and literature review

    Institute of Scientific and Technical Information of China (English)

    于金录; 曲丽梅; 李叶; 王柏; 王宏磊

    2011-01-01

    Objective To investigate the clinical presentation,imaging features and treatment experience of cystic cavernous malformations (CMs) in the cerebellopontine angle (CPA).Methods Three patients with the CMs of the CPA between 2005 and 2010 in our institute were summarised.Five patients from MEDLINE search of the English literature from 1985 to 2010 for CMs of the CPA were identified.We reviewed the characteristics of these 5 cases and our cases.Results Their presenting symptoms of 5 cases in the literature included headache,injury of cranial nerves in the CPA and cerebellar symptoms.But they did not show signs of brain stem compression.MRI and/or CT scans showed that the lesions in the eight cases of CMs all had solid and cystic components,and no adhesion with internal auditory canal and skull base dura mater was present in the CPA.Despite the fact that cystic CMs also involved cranial nerves,cerebellum,brainstem and arteries,they could be separated from these surrounding structures thanked to the presence of well - margined adhesion,which was contrary to solid CMs.We reported three cystic CMs of the CPA in our institute that was the same as the above.Conclusion Although cystic CMs of the CPA had no established imaging features,a diagnosis of CMs may be suspected when a cystic lesion is present in the CPA and does not involve internal acoustic meatus or dura matter of the skull base.Skillful microsurgical techniques will secure good outcomes for patients with cystic CMs in the CPA.%目的 总结小脑脑桥角(CPA)区海绵状血管畸形(CMs)的临床表现、影像学特征及治疗特点.方法 2005年6月至2010年6月我科共收治CPA区CMs病例3例,进行报告.搜索MEDLINE上自1985年至2010年文献查到此类病例5例,进行文献复习.结果 文献复习的5例CMs临床表现为脑神经及小脑受累症状,但无脑干受压症状;影像见CMs均呈囊实性,与内听道及颅底硬膜无粘连;术中见CMs与周边结构有粘连,但可进行分

  4. 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

  5. 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

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    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.

  6. 神经内镜下桥小脑角区手术入路的解剖学研究%Anatomical study of surgical approach to cerebellopontine angle under neuroendoscope

    Institute of Scientific and Technical Information of China (English)

    宋英; 师蔚; 马向科

    2011-01-01

    Objective To evaluate the application of three kinds of approach to the cerebellopontine angle under neuroendoscope. Methods Suboccipital retrosigmoid extracerebellar keyhole approach, suboccipital retrosigmoid infratentorial-supracerebellar keyhole approach and suboccipital retrosigmoid inferior floccular process keyhole approach were simulated under neuroendoscope respectively, and the surgical routes and anatomical landmarks to the root exit/entry zoon (REZ) of the V , Ⅳ, K cranial nerves were defined. Results The REZ of the cranial nerves V, VII and IX were observed through the suboccipital retrosigmoid extracerebellar keyhole approach, and the landmarks covered Meckel cave, internal auditory foramen, jugular foramen and cranial nerves V, Ⅳ, Ⅷ, K. The structure from the REZ of cranial nerve V to Meckel cave were explored through suboccipital retrosigmoid infratentorial-supracerebellar keyhole approach, and the landmarks covered the petrosal vein, cranial nerve V and Meckel cave. The REZ of the cranial nerves K and VD were explored via suboccipital retrosigmoid infrafloccular process keyhole approach, and the landmarks covered the choroid plexus of the fourth ventricle and floccular process. Conclusions Infratentorial-supracerebellar keyhole approach is superior to extracerebellar keyhole approach for microvascular decompression of the cranial nerve V, while infrafloccular process keyhole approach is superior to extracerebellar keyhole approach for microvascular decompression of the cranial nerve VD or IX.%目的 探讨神经内镜下桥小脑角区3种手术入路的应用价值.方法 在神经内镜下分别模拟枕下乙状窦后小脑外侧锁孔入路、枕下乙状窦后幕下小脑上锁孔入路、枕下乙状窦后绒球下锁孔入路,确定到三叉神经出入脑干区(REZ)、面神经REZ及舌咽神经REZ的手术路径及解剖定位标志.结果 枕下乙状窦后小脑外侧锁孔入路可探查三叉神经REZ、面神经REZ、舌咽神

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

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    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

  8. Imaging findings of cerebellopontine angle cistern melanocytoma : a case report

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    Kim, Sung Mi; Choi, Jin Ok; Joo, Myung Jin [Presbyterian Medical Center, Chunju (Korea, Republic of)

    2000-03-01

    Because melanocytes are found throughout the leptomeninges, primary melanotic pigmented tumors such as pigmented meningioma, malignant melanoma, melanoblastosis, and melanocytoma can arise from this region. Melanocytomas have been described in the literature as isodense or hyperdense compared with brain parenchyme, as seen on noncontrast-enhanced CT, and as showing relatively homogeneous enhancement MR imaging demonstrates a high signal on T1-weighted images, and an iso to hypointense signal on T2-weighted images. We report the imaging findings of a melanocytoma that showed hyperdense attenuation on precontrast CT with homogeneous enhancement and hyperintense signal intensity on T1-weighted images and dark signal intensity enhancement on T2-weighted images, and also review the literature. (author)

  9. Circumscribed Ciliochoroidal Effusion Presenting as an Acute Angle Closure Attack

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    Lipa, Roslyn Kathryn Manrique; Sánchez, María Eugenia González; Ordovas, Carlos Antonio Hijar; Aragües, Abel Rojo; Borque, Carmen Garcia

    2017-01-01

    Purpose: To report a case of choroidal effusion probably caused by angiotensin receptor II blocker. Case Report: A 52-year-old man with aplastic anemia and high blood pressure who developed unilateral acute angle closure glaucoma after receiving oral cyclosporine and angiotensin II receptor blocker (losartan). Ophthalmic examination revealed visual acuity of 20/30 in the left eye, mild mydriasis, iris bombe, no anterior chamber reaction, mild conjunctival hyperemia, and the intraocular pressure of 30 mmHg. After laser YAG iridotomy, funduscopy was performed showing a choroidal circumscribed lesion at the inferotemporal quadrant. Diagnostic tests ruled out any inflammatory or malignancy process, and the choroidal lesion spontaneously disappeared. After 20 months of follow-up, patient's ocular remained stable. Conclusion: This is the third case of choroidal effusion associated with angiotensin II receptor blockers. Since idiosyncratic ciliochoroidal effusion is a diagnosis of exclusion, it is mandatory to rule out more frequent causes, such as inflammatory or malignant processes. PMID:28299016

  10. Bilateral acute angle closure glaucoma as a presentation of isolated microspherophakia in an adult: case report

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    Gupta Amod

    2006-07-01

    Full Text Available Abstract Background Bilateral simultaneous angle closure glaucoma is a rare entity. To our knowledge this is the first reported case of bilateral acute angle-closure glaucoma secondary to isolated microspherophakia in an adult. Case presentation A 45-year-old woman presented with bilateral acute angle closure glaucoma, with a patent iridotomy in one eye. Prolonged miotic use prior to presentation had worsened the pupillary block. The diagnosis was not initially suspected, and the patient was subjected to pars-plana lensectomy and anterior vitrectomy for a presumed ciliary block glaucoma. The small spherical lens was detected intraoperatively, and spherophakia was diagnosed in retrospect. She had no systemic features of any of the known conditions associated with spherophakia. Pars-plana lensectomy both eyes controlled the intraocular pressure successfully. Conclusion This case demonstrates the importance of considering the diagnosis of isolated microspherophakia in any case of bilateral acute angle closure glaucoma. Lensectomy appears to be an effective first-line strategy for managing these patients.

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

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    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

  12. Ocular Adnexal Lymphoma Presenting as Refractory Unilateral Open-angle Glaucoma.

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    Sears, Nathaniel C; Singh, Annapurna; Singh, Arun D

    2016-08-01

    We report a single case of masquerade glaucoma caused by increased episcleral venous pressure from adnexal lymphoma. The patient presented as a referral for unilateral glaucoma with intraocular pressures (IOPs) consistently >40 mm Hg (right eye). We present data conclusively demonstrating extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue in the involved eye, and provide an account of the treatment of the tumor with sustained regression and complete resolution of his elevated IOP. We conclude with a discussion of the proposed mechanism. This case serves as a reminder that unilateral open-angle glaucoma can be a sign of indolent ocular adnexal lymphoma. The case also provides a useful model for increased IOP with orbital lesions.

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

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    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. Angle- and polarization-insensitive, small area, subtractive color filters via a-Si nanopillar arrays (Conference Presentation)

    Science.gov (United States)

    Fountaine, Katherine T.; Ito, Mikinori; Pala, Ragip; Atwater, Harry A.

    2016-09-01

    Spectrally-selective nanophotonic and plasmonic structures enjoy widespread interest for application as color filters in imaging devices, due to their potential advantages over traditional organic dyes and pigments. Organic dyes are straightforward to implement with predictable optical performance at large pixel size, but suffer from inherent optical cross-talk and stability (UV, thermal, humidity) issues and also exhibit increasingly unpredictable performance as pixel size approaches dye molecule size. Nanophotonic and plasmonic color filters are more robust, but often have polarization- and angle-dependent optical response and/or require large-range periodicity. Herein, we report on design and fabrication of polarization- and angle-insensitive CYM color filters based on a-Si nanopillar arrays as small as 1um2, supported by experiment, simulation, and analytic theory. Analytic waveguide and Mie theories explain the color filtering mechanism- efficient coupling into and interband transition-mediated attenuation of waveguide-like modes—and also guided the FDTD simulation-based optimization of nanopillar array dimensions. The designed a-Si nanopillar arrays were fabricated using e-beam lithography and reactive ion etching; and were subsequently optically characterized, revealing the predicted polarization- and angle-insensitive (±40°) subtractive filter responses. Cyan, yellow, and magenta color filters have each been demonstrated. The effects of nanopillar array size and inter-array spacing were investigated both experimentally and theoretically to probe the issues of ever-shrinking pixel sizes and cross-talk, respectively. Results demonstrate that these nanopillar arrays maintain their performance down to 1um2 pixel sizes with no inter-array spacing. These concepts and results along with color-processed images taken with a fabricated color filter array will be presented and discussed.

  15. 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.

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

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    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.

  17. Massive primary cerebellopontine angle melanocytoma in an 11 year old child: A case report and review of literature

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    Amresh Bhaganagare

    2013-01-01

    Full Text Available A rare case of meningeal melanocytoma in an 11 year-old girl is reported. The tumor was sub-totally resected. She received no adjuvant treatment and is symptom-free at the follow-up of 8 months.

  18. Presentation

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    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.

  19. Presentation

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    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

  20. Presentation

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    Helmut Renders

    2008-10-01

    Full Text Available We present to our esteemed readers the second edition of our journal for 2008. We have chosen the theme “The life and work of Prof. Dr. Jürgen Moltmann” as its special emphasis. It is our way to pay homage to J. Moltmann in the year the Universidade Metodista de São Paulo awards him an honorary Doctor Honoris Causa degree. Sincethe seventies, Moltmann and Latin America have been in dialog. In his emblematic work “A Theology of Liberation”, Gustavo Gutiérrez, the Catholic, discussed with Moltmann, the Reformed, the relationship between eschatology and history (GUTIÉRREZ, Gustavo.Teologia da Libertação. 5ª edição. Petrópolis, RJ: Vozes, 1985, p. 27, 137-139. A dialog held in the premises of IMS, which nowadays is called UMESP, has produced the little book “Passion for life” (MOLTMANN, Jürgen. Paixão pela vida. São Paulo, SP: ASTE - Associaçãode Seminários Teológicos Evangélicos, 1978.In the following years, the wide theological work of J. Moltmann went all the way from debates to congresses and has conquered the classrooms. Most probably, J. Moltmann is nowadays the most widely read European author in Brazilian theological seminaries. Thisrecognition can only be held in unison and the wide response to our request for articles confirms the huge repercussion that Moltmann’s work has been having up to today in Brazil. The ecumenical theologian J. Moltmann is ecumenically read. We believe that thisway we may be better equipped to answer to anyone who asks us for the reason there is hope in us. We have organized the articles on J. Moltmann’s theology according to the original publication date of the books dealt with in each essay. We also communicate that some articles which were originally requested for this edition of the journal will be published in the journal Estudos de Regilião in May 2009.As it is usual with the journal Caminhando, we have, besides this thematic emphasis, yet other contributions in the areas of

  1. Presentation

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    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

  2. The need for skull radiography in patients presenting for CT

    Energy Technology Data Exchange (ETDEWEB)

    Tress, B.M.

    1983-01-01

    One thousand patients had both CT of the head and a conventional skull series of radiographs. Radiographic findings were abnormal in 250 patients (25%), but only 64 patients (6.4%) had diagnostically significant abnormalities at radiography that were not detected by CT. If the 163 patients who presented after acute trauma were excluded from the series, only 39 (4.7%) of the remaining patients had radiographically significant abnormal findings that were not seen at CT, and only two (0.2%) of these abnormalities could not be diagnosed by a lateral skull radiograph alone. In only five patients (0.5%) was the management actively changed because an abnormaltiy that was detected at skull radiography was not detected at CT. Thus, in nontrauma patients who have stroke, epilepsy, dementia, or non-specific symptoms without focal signs, or have recently undergone craniotomy, and who have been referred for CT, skull radiographs are not justified. In the patient with a history and findings that are strongly suggestive of a pathological disorder anywhere other than in the sella turcica, cerebello-pontine angle, and paranasal sinuses, only the lateral skull radiograph should be obtained after CT, and only if CT is equivocal.

  3. Intermittent facial spasms as the presenting sign of a recurrent pleomorphic adenoma

    Science.gov (United States)

    Machado, Rosalie A; Moubayed, Sami P; Khorsandi, Azita; Hernandez-Prera, Juan C; Urken, Mark L

    2017-01-01

    The intimate anatomical relationship of the facial nerve to the parotid parenchyma has a significant influence on the presenting signs and symptoms, diagnosis and treatment of parotid neoplasms. However, to our knowledge, hyperactivity of this nerve, presenting as facial spasm, has never been described as the presenting sign or symptom of a parotid malignancy. We report a case of carcinoma arising in a recurrent pleomorphic adenoma of the left parotid gland (i.e., carcinoma ex pleomorphic adenoma) that presented with hemifacial spasms. We outline the differential diagnosis of hemifacial spasm as well as a proposed pathophysiology. Facial paralysis, lymph node enlargement, skin involvement, and pain have all been associated with parotid malignancies. To date the development of facial spasm has not been reported with parotid malignancies. The most common etiologies for hemifacial spasm are vascular compression of the ipsilateral facial nerve at the cerebellopontine angle (termed primary or idiopathic) (62%), hereditary (2%), secondary to Bell’s palsy or facial nerve injury (17%), and hemifacial spasm mimickers (psychogenic, tics, dystonia, myoclonus, myokymia, myorthythmia, and hemimasticatory spasm) (17%). Hemifacial spasm has not been reported in association with a malignant parotid tumor but must be considered in the differential diagnosis of this presenting symptom. PMID:28246588

  4. A new angle on the Euler angles

    Science.gov (United States)

    Markley, F. Landis; Shuster, Malcolm D.

    1995-01-01

    We present a generalization of the Euler angles to axes beyond the twelve conventional sets. The generalized Euler axes must satisfy the constraint that the first and the third are orthogonal to the second; but the angle between the first and third is arbitrary, rather than being restricted to the values 0 and pi/2, as in the conventional sets. This is the broadest generalization of the Euler angles that provides a representation of an arbitrary rotation matrix. The kinematics of the generalized Euler angles and their relation to the attitude matrix are presented. As a side benefit, the equations for the generalized Euler angles are universal in that they incorporate the equations for the twelve conventional sets of Euler angles in a natural way.

  5. 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…

  6. Accuracy of single-sequence MRI for investigation of the fluid-filled spaces in the inner ear and cerebellopontine angle.

    Science.gov (United States)

    Lemmerling, M; De Praeter, G; Caemaert, J; Van Cauwemberge, P; De Reuck, J; Vermeersch, H; Kunnen, M

    1999-04-01

    We prospectively studied 163 patients referred for MRI of the temporal bone. A presumed diagnosis was made using only one of three sequences: a single thick (12 mm) slice fast T2-sequence, 3D fourier transform constructive interference in steady state (3DFT-CISS) sequence and a gadolinium-enhanced T1-weighted sequence. The visibility of the cochlea, vestibule and superior, lateral and posterior semicircular canals of normal temporal bones was assessed on the T2-weighted images: they were almost always visible (98-100%), with exception of the superior semicircular canal, seen in only 35% of cases. The images were interpreted as abnormal in 34 patients (21%). Using only the fast T2-weighted, 3DFT-CISS and gadolinium-enhanced T1-weighted sequences a presumed false positive diagnosis was made in 5, 1 and 0 cases and a false negative diagnosis in 2, 2 and 4 cases respectively. The overall reliability of the thick-section fast T2-weighted images is limited. This study suggests that a combination of gadolinium-enhanced T1-weighted and 3DFT-CISS images can be considered the gold standard for temporal bone MRI and neither sequence performed separately is as accurate as both together.

  7. [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.

  8. 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…

  9. 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....

  10. Generalization of the Euler Angles

    Science.gov (United States)

    Bauer, Frank H. (Technical Monitor); Shuster, Malcolm D.; Markley, F. Landis

    2002-01-01

    It is shown that the Euler angles can be generalized to axes other than members of an orthonormal triad. As first shown by Davenport, the three generalized Euler axes, hereafter: Davenport axes, must still satisfy the constraint that the first two and the last two axes be mutually perpendicular if these axes are to define a universal set of attitude parameters. Expressions are given which relate the generalized Euler angles, hereafter: Davenport angles, to the 3-1-3 Euler angles of an associated direction-cosine matrix. The computation of the Davenport angles from the attitude matrix and their kinematic equation are presented. The present work offers a more direct development of the Davenport angles than Davenport's original publication and offers additional results.

  11. 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 par......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...

  12. Glaucoma, Open-Angle

    Science.gov (United States)

    ... Programs Home > Statistics and Data > Glaucoma, Open-angle Glaucoma, Open-angle Open-angle Glaucoma Defined In open-angle glaucoma, the fluid passes ... 2010 2010 U.S. Age-Specific Prevalence Rates for Glaucoma by Age and Race/Ethnicity The prevalence of ...

  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. Contact Angle Goniometer

    Data.gov (United States)

    Federal Laboratory Consortium — Description:The FTA32 goniometer provides video-based contact angle and surface tension measurement. Contact angles are measured by fitting a mathematical expression...

  15. 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.

  16. Photoelectric angle converter

    Science.gov (United States)

    Podzharenko, Volodymyr A.; Kulakov, Pavlo I.

    2001-06-01

    The photo-electric angle transmitter of rotation is offered, at which the output voltage is linear function of entering magnitude. In a transmitter the linear phototransducer is used on the basis of pair photo diode -- operating amplifier, which output voltage is linear function of the area of an illuminated photosensitive stratum, and modulator of a light stream of the special shape, which ensures a linear dependence of this area from an angle of rotation. The transmitter has good frequent properties and can be used for dynamic measurements of an angular velocity and angle of rotation, in systems of exact drives and systems of autocontrol.

  17. Angle-Ply Weaving

    Science.gov (United States)

    Farley, Gary L.

    1990-01-01

    Bias-direction or angle-ply weaving is proposed new process for weaving fibers along bias in conventional planar fabric or in complicated three-dimensional multilayer fabric preform of fiber-reinforced composite structure. Based upon movement of racks of needles and corresponding angle yarns across fabric as fabric being formed. Fibers woven along bias increases shear stiffness and shear strength of preform, increasing value of preform as structural member.

  18. Limited Angle Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ho Kyung; Cho, Min Kook; Kim, Seong Sik [Pusan National University, Busan (Korea, Republic of)

    2007-07-01

    In computed tomography (CT), many situations are restricted to obtain enough number of projections or views to avoid artifacts such as streaking and geometrical distortion in the reconstructed images. Speed of motion of an object to be imaged can limit the number of views. Cardiovascular imaging is a representative example. Size of an object can also limit the complete traverse motion or geometrical complexity can obscure to be imaged at certain range of angles. These situations are frequently met in industrial nondestructive testing and evaluation. Dental CT also suffers from similar situation because cervical spine causes less x-ray penetration from some directions such that the available information is not sufficient for standard reconstruction algorithms. The limited angle tomography is now greatly paid attention as a new genre in medical and industrial imaging, popularly known as digital tomosynthesis. In this study, we introduce a modified filtered backprojection method in limited angle tomography and demonstrate its application for the dental imaging.

  19. 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

  20. Dynamical angled brane

    Science.gov (United States)

    Maeda, Kei-ichi; Uzawa, Kunihito

    2016-12-01

    We discuss the dynamical D p -brane solutions describing any number of D p branes whose relative orientations are given by certain SU(2) rotations. These are the generalization of the static angled D p -brane solutions. We study the collision of the dynamical D3 brane with angles in type-II string theory, and show that the particular orientation of the smeared D3-brane configuration can provide an example of colliding branes if they have the same charges. Otherwise a singularity appears before D3 branes collide.

  1. 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...

  2. Contact angle hysteresis of microbead suspensions.

    Science.gov (United States)

    Waghmare, Prashant R; Mitra, Sushanta K

    2010-11-16

    Microbead suspensions are often used in microfluidic devices for transporting biomolecules. An experimental investigation on the wettability of microbead suspension is presented in this study. The variation in the surface tension and the equilibrium contact angle with the change in the volume fraction of the microbead is presented here. The surface tension of the microbead suspension is measured with the pendant drop technique, whereas the dynamic contact angle measurements, i.e., advancing and receding contact angles, are measured with the sessile drop technique. An equilibrium contact angle of a suspension with particular volume fraction is determined by computing an average over the measured advancing and receding contact angles. It is observed that the surface tension and the equilibrium contact angle determined from advancing and receding contact angles vary with the magnitude of the microbeads volume fraction in the suspension. A decrease in the surface tension with an increase in the volume fraction of the microbead suspension is observed. The advancement and the recession in contact line for dynamic contact angle measurements are achieved with the motorized dosing mechanism. For microbead suspensions, the advancement of the contact line is faster as compared to the recession of the contact line for the same flow rate. The presence of microbeads assists in the advancement and the recession of the contact line of the suspension. A decrease in the equilibrium contact angles with an increase in the microbead suspension volume fraction is observed. Inclusion of microbeads in the suspension increases the wetting capability for the considered combination of the microbead suspension and substrate. Finally, empirical correlations for the surface tension and the contact angle of the suspension as a function of microbead volume fraction are proposed. Such correlations can readily be used to develop mechanistic models for the capillary transport of microbead

  3. 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.

  4. Globographic visualisation of three dimensional joint angles.

    Science.gov (United States)

    Baker, Richard

    2011-07-07

    Three different methods for describing three dimensional joint angles are commonly used in biomechanics. The joint coordinate system and Cardan/Euler angles are conceptually quite different but are known to represent the same underlying mathematics. More recently the globographic method has been suggested as an alternative and this has proved particularly attractive for the shoulder joint. All three methods can be implemented in a number of ways leading to a choice of angle definitions. Very recently Rab has demonstrated that the globographic method is equivalent to one implementation of the joint coordinate system. This paper presents a rigorous analysis of the three different methods and proves their mathematical equivalence. The well known sequence dependence of Cardan/Euler is presented as equivalent to configuration dependence of the joint coordinate system and orientation dependence of globographic angles. The precise definition of different angle sets can be easily visualised using the globographic method using analogues of longitude, latitude and surface bearings with which most users will already be familiar. The method implicitly requires one axis of the moving segment to be identified as its principal axis and this can be extremely useful in helping define the most appropriate angle set to describe the orientation of any particular joint. Using this technique different angle sets are considered to be most appropriate for different joints and examples of this for the hip, knee, ankle, pelvis and axial skeleton are outlined.

  5. 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....

  6. Contact angle hysteresis explained.

    Science.gov (United States)

    Gao, Lichao; McCarthy, Thomas J

    2006-07-04

    A view of contact angle hysteresis from the perspectives of the three-phase contact line and of the kinetics of contact line motion is given. Arguments are made that advancing and receding are discrete events that have different activation energies. That hysteresis can be quantified as an activation energy by the changes in interfacial area is argued. That this is an appropriate way of viewing hysteresis is demonstrated with examples.

  7. Contact angle hysteresis, adhesion, and marine biofouling.

    Science.gov (United States)

    Schmidt, Donald L; Brady, Robert F; Lam, Karen; Schmidt, Dale C; Chaudhury, Manoj K

    2004-03-30

    Adhesive and marine biofouling release properties of coatings containing surface-oriented perfluoroalkyl groups were investigated. These coatings were prepared by cross-linking a copolymer of 1H,1H,2H,2H-heptadecafluorodecyl acrylate and acrylic acid with a copolymer of poly(2-isopropenyl-2-oxazoline) and methyl methacrylate at different molar ratios. The relationships between contact angle, contact angle hysteresis, adhesion, and marine biofouling were studied. Adhesion was determined by peel tests using pressure-sensitive adhesives. The chemical nature of the surfaces was studied by using X-ray photoelectron spectroscopy. Resistance to marine biofouling of an optimized coating was studied by immersion in seawater and compared to previous, less optimized coatings. The adhesive release properties of the coatings did not correlate well with the surface energies of the coatings estimated from the static and advancing contact angles nor with the amount of fluorine present on the surface. The adhesive properties of the surfaces, however, show a correlation with water receding contact angles and contact angle hysteresis (or wetting hysteresis) resulting from surface penetration and surface reconstruction. Coatings having the best release properties had both the highest cross-link density and the lowest contact angle hysteresis. An optimized coating exhibited unprecedented resistance to marine biofouling. Water contact angle hysteresis appears to correlate with marine biofouling resistance.

  8. 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.

  9. 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.

  10. Measurement of the angle alpha at BABAR

    CERN Document Server

    Pérez, A

    2009-01-01

    We present recent measurements of the CKM angle alpha using data collected by the BABAR detector at the PEP-II asymmetric-energy e^+e^- collider at the SLAC National Accelerator Laboratory, operating at the Upsilon(4S) resonance. We present constraints on alpha from B->pipi, B->rhorho and B->rhopi decays.

  11. Heterodyne Interferometer Angle Metrology

    Science.gov (United States)

    Hahn, Inseob; Weilert, Mark A.; Wang, Xu; Goullioud, Renaud

    2010-01-01

    A compact, high-resolution angle measurement instrument has been developed that is based on a heterodyne interferometer. The common-path heterodyne interferometer metrology is used to measure displacements of a reflective target surface. In the interferometer setup, an optical mask is used to sample the measurement laser beam reflecting back from a target surface. Angular rotations, around two orthogonal axes in a plane perpendicular to the measurement- beam propagation direction, are determined simultaneously from the relative displacement measurement of the target surface. The device is used in a tracking telescope system where pitch and yaw measurements of a flat mirror were simultaneously performed with a sensitivity of 0.1 nrad, per second, and a measuring range of 0.15 mrad at a working distance of an order of a meter. The nonlinearity of the device is also measured less than one percent over the measurement range.

  12. Equilibrium contact angle or the most-stable contact angle?

    Science.gov (United States)

    Montes Ruiz-Cabello, F J; Rodríguez-Valverde, M A; Cabrerizo-Vílchez, M A

    2014-04-01

    It is well-established that the equilibrium contact angle in a thermodynamic framework is an "unattainable" contact angle. Instead, the most-stable contact angle obtained from mechanical stimuli of the system is indeed experimentally accessible. Monitoring the susceptibility of a sessile drop to a mechanical stimulus enables to identify the most stable drop configuration within the practical range of contact angle hysteresis. Two different stimuli may be used with sessile drops: mechanical vibration and tilting. The most stable drop against vibration should reveal the changeless contact angle but against the gravity force, it should reveal the highest resistance to slide down. After the corresponding mechanical stimulus, once the excited drop configuration is examined, the focus will be on the contact angle of the initial drop configuration. This methodology needs to map significantly the static drop configurations with different stable contact angles. The most-stable contact angle, together with the advancing and receding contact angles, completes the description of physically realizable configurations of a solid-liquid system. Since the most-stable contact angle is energetically significant, it may be used in the Wenzel, Cassie or Cassie-Baxter equations accordingly or for the surface energy evaluation.

  13. Investigation of drop dynamic contact angle on copper surface

    Directory of Open Access Journals (Sweden)

    Orlova Evgenija

    2015-01-01

    Full Text Available This paper presents experimental results of the studying the effect of surface roughness, microstructure and flow rate on the dynamic contact angle at spreading of distilled non deaerate water drop on a solid horizontal substrates. Copper substrates with different roughness have been investigated. For each substrate static contact angles depending on volume flow rate have been obtained using shadow system. Increasing the volume flow rate resulted in an increase of the static contact angle. It was found that with increasing surface roughness dynamic contact angle arises. Also difference in formation of the equilibrium contact angle at low and high rates of drop growth has been detected.

  14. 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.

  15. Investigation of drop dynamic contact angle on copper surface

    Science.gov (United States)

    Orlova, Evgenija; Feoktistov, Dmitriy; Kuznetsov, Geniy

    2015-01-01

    This paper presents experimental results of the studying the effect of surface roughness, microstructure and flow rate on the dynamic contact angle at spreading of distilled non deaerate water drop on a solid horizontal substrates. Copper substrates with different roughness have been investigated. For each substrate static contact angles depending on volume flow rate have been obtained using shadow system. Increasing the volume flow rate resulted in an increase of the static contact angle. It was found that with increasing surface roughness dynamic contact angle arises. Also difference in formation of the equilibrium contact angle at low and high rates of drop growth has been detected.

  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. 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

  19. 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...

  20. 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.

  1. 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.

  2. Investigation of drop dynamic contact angle on copper surface

    OpenAIRE

    Orlova Evgenija; Feoktistov Dmitriy; Kuznetsov Geniy

    2015-01-01

    This paper presents experimental results of the studying the effect of surface roughness, microstructure and flow rate on the dynamic contact angle at spreading of distilled non deaerate water drop on a solid horizontal substrates. Copper substrates with different roughness have been investigated. For each substrate static contact angles depending on volume flow rate have been obtained using shadow system. Increasing the volume flow rate resulted in an increase of the static contact angle. It...

  3. Measurement of the angle alpha at BABAR

    Energy Technology Data Exchange (ETDEWEB)

    Perez, A.; /Orsay, LAL

    2009-06-25

    The authors present recent measurements of the CKM angle {alpha} using data collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at the SLAC National Accelerator Laboratory, operating at the {Upsilon}(4S) resonance. They present constraints on {alpha} from B {yields} {pi}{pi}, B {yields} {rho}{rho} and B {yields} {rho}{pi} decays.

  4. Hysteresis during contact angles measurement.

    Science.gov (United States)

    Diaz, M Elena; Fuentes, Javier; Cerro, Ramon L; Savage, Michael D

    2010-03-15

    A theory, based on the presence of an adsorbed film in the vicinity of the triple contact line, provides a molecular interpretation of intrinsic hysteresis during the measurement of static contact angles. Static contact angles are measured by placing a sessile drop on top of a flat solid surface. If the solid surface has not been previously in contact with a vapor phase saturated with the molecules of the liquid phase, the solid surface is free of adsorbed liquid molecules. In the absence of an adsorbed film, molecular forces configure an advancing contact angle larger than the static contact angle. After some time, due to an evaporation/adsorption process, the interface of the drop coexists with an adsorbed film of liquid molecules as part of the equilibrium configuration, denoted as the static contact angle. This equilibrium configuration is metastable because the droplet has a larger vapor pressure than the surrounding flat film. As the drop evaporates, the vapor/liquid interface contracts and the apparent contact line moves towards the center of the drop. During this process, the film left behind is thicker than the adsorbed film and molecular attraction results in a receding contact angle, smaller than the equilibrium contact angle.

  5. Positron Emission Mammography with Multiple Angle Acquisition

    Energy Technology Data Exchange (ETDEWEB)

    Mark F. Smith; Stan Majewski; Raymond R. Raylman

    2002-11-01

    Positron emission mammography (PEM) of F-18 fluorodeoxyglucose (FbG) uptake in breast tumors with dedicated detectors typically has been accomplished with two planar detectors in a fixed position with the breast under compression. The potential use of PEM imaging at two detector positions to guide stereotactic breast biopsy has motivated us to use PEM coincidence data acquired at two or more detector positions together in a single image reconstruction. Multiple angle PEM acquisition and iterative image reconstruction were investigated using point source and compressed breast phantom acquisitions with 5, 9, 12 and 15 mm diameter spheres and a simulated tumor:background activity concentration ratio of 6:1. Image reconstruction was performed with an iterative MLEM algorithm that used coincidence events between any two detector pixels on opposed detector heads at each detector position. This present study compared two acquisition protocols: 2 angle acquisition with detector angular positions of -15 and +15 degrees and 11 angle acquisition with detector positions spaced at 3 degree increments over the range -15 to +15 degrees. Three-dimensional image resolution was assessed for the point source acquisitions, and contrast and signal-to-noise metrics were evaluated for the compressed breast phantom with different simulated tumor sizes. Radial and tangential resolutions were similar for the two protocols, while normal resolution was better for the 2 angle acquisition. Analysis is complicated by the asymmetric point spread functions. Signal- to-noise vs. contrast tradeoffs were better for 11 angle acquisition for the smallest visible 9 mm sphere, while tradeoff results were mixed for the larger and more easily visible 12 mm and 15 mm diameter spheres. Additional study is needed to better understand the performance of limited angle tomography for PEM. PEM tomography experiments with complete angular sampling are planned.

  6. Positron Emission Mammography with Multiple Angle Acquisition

    Energy Technology Data Exchange (ETDEWEB)

    Mark F. Smith; Stan Majewski; Raymond R. Raylman

    2002-11-01

    Positron emission mammography (PEM) of F-18 fluorodeoxyglucose (FDG) uptake in breast tumors with dedicated detectors typically has been accomplished with two planar detectors in a fixed position with the breast under compression. The potential use of PEM imaging at two detector positions to guide stereotactic breast biopsy has motivated us to use PEM coincidence data acquired at two or more detector positions together in a single image reconstruction. Multiple angle PEM acquisition and iterative image reconstruction were investigated using point source and compressed breast phantom acquisitions with 5, 9, 12 and 15 mm diameter spheres and a simulated tumor:background activity concentration ratio of 6:1. Image reconstruction was performed with an iterative MLEM algorithm that used coincidence events between any two detector pixels on opposed detector heads at each detector position. This present study compared two acquisition protocols: 2 angle acquisition with detector angular positions of -15 and +15 degrees and 11 angle acquisition with detector positions spaced at 3 degree increments over the range -15 to +15 degrees. Three- dimensional image resolution was assessed for the point source acquisitions, and contrast and signal-to-noise metrics were evaluated for the compressed breast phantom with different simulated tumor sizes. Radial and tangential resolutions were similar for the two protocols, while normal resolution was better for the 2 angle acquisition. Analysis is complicated by the asymmetric point spread functions. Signal- to-noise vs. contrast tradeoffs were better for 11 angle acquisition for the smallest visible 9 mm sphere, while tradeoff results were mixed for the larger and more easily visible 12 mm and 15 mm diameter spheres. Additional study is needed to better understand the performance of limited angle tomography for PEM. PEM tomography experiments with complete angular sampling are planned.

  7. Influence of Atmospheric Refraction on Horizontal Angle Surveying

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhenglu; DENG Yong; LUO Changlin; MEI Wensheng

    2006-01-01

    Side-refraction is the main error source of horizontal angle surveying, but it has little influence on the sides by analyzing the influence of atmospheric-infraction on the ultrahigh-precision side and angle surveying. Choosing oriented direction is crucial to distance and angle measurement in triangulateration network. How to select the oriented direction during angle measurement is presented, and the means to check the quality of auto-surveying with Georobot is brought forward as well. At last some solutions to reduce the influence of side-refraction while disposing and surveying ultrahigh-precision triangulateration network are put forward.

  8. Creation of a multi-reference-angle comparator

    Science.gov (United States)

    Bručas, Domantas; Giniotis, Vytautas

    2009-03-01

    Many geodetic and industrial instruments utilize precise angle determination. Metrological calibration and testing of such devices is very complicated, due to the large number of angular position values generated, and often cannot be accomplished using classical means of angle determination. Therefore a special comparator (test rig) capable of calibration geodetic and other angle-measuring instruments and implementing multiple references for angle determination has been created. Several modernized optical devices were used on the test rig, together with the implementation of a special calibration method. In this paper the construction of the rig, modernization of the optical devices, calibration, and some results of measurements are presented.

  9. As-placed contact angles for sessile drops.

    Science.gov (United States)

    Tadmor, Rafael; Yadav, Preeti S

    2008-01-01

    As-placed contact angle is the contact angle a drop adapts as a result of its placement on a surface. As expected, the as-placed contact angle, thetaAP, of a sessile drop on a horizontal surface decreases with the drop size due to the increase in hydrostatic pressure. We present a theoretical prediction for thetaAP which shows that it is a unique function of the advancing contact angle, thetaA, drop size, and material properties (surface tensions and densities). We test our prediction with published and new data. The theory agrees with the experiments. From the relation of the as-placed contact angle to drop size the thermodynamic equilibrium contact angle is also calculated.

  10. 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.

  11. 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).

  12. Oriented angles in affine space

    Directory of Open Access Journals (Sweden)

    Włodzimierz Waliszewski

    2004-05-01

    Full Text Available The concept of a smooth oriented angle in an arbitrary affine space is introduced. This concept is based on a kinematics concept of a run. Also, a concept of an oriented angle in such a space is considered. Next, it is shown that the adequacy of these concepts holds if and only if the affine space, in question, is of dimension 2 or 1.

  13. Properties of tangential and radial angles of muons in EAS

    OpenAIRE

    Zabierowski, J.; Daumiller, K.; Doll, P.

    2002-01-01

    Tangential and radial angles of muons in EAS, a useful concept in investigation of the muon production height, can be used also for the investigation of the muon momenta. A parameter zeta, being a combination of tangential and radial angles, is introduced and its possible applications in investigation of muons in showers are presented.

  14. Present time

    CERN Document Server

    Romero, Gustavo E

    2014-01-01

    The idea of a moving present or `now' seems to form part of our most basic beliefs about reality. Such a present, however, is not reflected in any of our theories of the physical world. I show in this article that presentism, the doctrine that only what is present exists, is in conflict with modern relativistic cosmology and recent advances in neurosciences. I argue for a tenseless view of time, where what we call `the present' is just an emergent secondary quality arising from the interaction of perceiving self-conscious individuals with their environment. I maintain that there is no flow of time, but just an ordered system of events.

  15. Statistical analysis of Contact Angle Hysteresis

    Science.gov (United States)

    Janardan, Nachiketa; Panchagnula, Mahesh

    2015-11-01

    We present the results of a new statistical approach to determining Contact Angle Hysteresis (CAH) by studying the nature of the triple line. A statistical distribution of local contact angles on a random three-dimensional drop is used as the basis for this approach. Drops with randomly shaped triple lines but of fixed volumes were deposited on a substrate and their triple line shapes were extracted by imaging. Using a solution developed by Prabhala et al. (Langmuir, 2010), the complete three dimensional shape of the sessile drop was generated. A distribution of the local contact angles for several such drops but of the same liquid-substrate pairs is generated. This distribution is a result of several microscopic advancing and receding processes along the triple line. This distribution is used to yield an approximation of the CAH associated with the substrate. This is then compared with measurements of CAH by means of a liquid infusion-withdrawal experiment. Static measurements are shown to be sufficient to measure quasistatic contact angle hysteresis of a substrate. The approach also points towards the relationship between microscopic triple line contortions and CAH.

  16. 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.

  17. Target Localization Based on Angle of Arrivals

    Institute of Scientific and Technical Information of China (English)

    Yi-Chao Cao

    2007-01-01

    Mobile location using angle of arrival (AOA) measurements has received considerable attention. This paper presents an approximation of maximum likelihood estimator (MLE) for localizing a source based on AOA measurements. By introducing an intermediate variable, the nonlinear equations relating AOA estimates can be transformed into a set of equations which are linear in the unknown parameters. It is an approximate realization of the MLE. Simulations show that the proposed algorithm outperforms the previous contribution.

  18. Computer programs for calculation of sting pitch and roll angles required to obtain angles of attack and sideslip on wind tunnel models

    Science.gov (United States)

    Peterson, John B., Jr.

    1988-01-01

    Two programs have been developed to calculate the pitch and roll angles of a wind-tunnel sting drive system that will position a model at the desired angle of attack and and angle of sideslip in the wind tunnel. These programs account for the effects of sting offset angles, sting bending angles and wind-tunnel stream flow angles. In addition, the second program incorporates inputs from on-board accelerometers that measure model pitch and roll with respect to gravity. The programs are presented in the report and a description of the numerical operation of the programs with a definition of the variables used in the programs is given.

  19. Orientation angle workspaces of planar serial three-link manipulators

    Institute of Scientific and Technical Information of China (English)

    DAI; Jian; S

    2009-01-01

    This paper presents a classification on the workspaces of planar serial three-link manipulators, that is, position workspace and orientation angle workspace. Position workspace indicates the region reached by the reference point on the end-effector. 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, reachable position workspace can be di- vided into several Grashof intervals and non-Grashof intervals. The calculation equations of orientation angle workspace are deduced in three situations according to the relationships among four link lengths in the virtual four-bar chain. Three examples are given for three kinds of relationship of link lengths. The orientation angle workspace of extended groups, that is, two of the three link lengths equal, and the orientation angle workspace when the reference point on the end-effector moves along a non-radial direction are also discussed. A program is developed to calculate orientation angle workspaces and output variation curves of orientation angle workspace and key data within the position workspace. The approach and program in this paper can be used for fast calculation and identification of the variation rule of the orientation angle workspace of any given planar serial three-link manipulator on the basis of its link parameters, and for the design of a highly dexterous serial manipulator with proposed link rela- tions.

  20. Orientation angle workspaces of planar serial three-link manipulators

    Institute of Scientific and Technical Information of China (English)

    LI RuiQin; DAI Jian S

    2009-01-01

    This paper presents a classification on the workspaces of planar serial three-link manipulators, that is,position workspace and orientation angle workspace. Position workspace indicates the region reached by the reference point on the end-effector. 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, reachable position workspace can be divided into several Grashof intervals and non-Grashof intervals. The calculation equations of orientation angle workspace are deduced in three situations according to the relationships among four link lengths in the virtual four-bar chain. Three examples are given for three kinds of relationship of link lengths.The orientation angle workspace of extended groups, that is, two of the three link lengths equal, end the orientation angle workspace when the reference point on the end-effector moves along a non-radial direction are also discussed. A program is developed to calculate orientation angle workspaces and output variation curves of orientation angle workspace and key data within the position workspace. The approach and program in this paper can be used for fast calculation and identification of the variation rule of the orientation angle workspace of any given planar serial three-link manipulator on the basis of its link parameters, and for the design of a highly dexterous serial manipulator with proposed link relations.

  1. 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...

  2. 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.

  3. 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.

  4. Information Presentation

    Science.gov (United States)

    Holden, K.L.; Boyer, J.L.; Sandor, A.; Thompson, S.G.; McCann, R.S.; Begault, D.R.; Adelstein, B.D.; Beutter, B.R.; Stone, L.S.

    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. The major areas of work, or subtasks, within this DRP are: 1) Displays, 2) Controls, 3) Electronic Procedures and Fault Management, and 4) Human Performance Modeling. This DRP is a collaborative effort between researchers at Johnson Space Center and Ames Research Center.

  5. 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.

  6. Scaling of misorientation angle distributions

    DEFF Research Database (Denmark)

    Hughes, D.A.; Chrzan, D.C.; Liu, Q.

    1998-01-01

    The measurement of misorientation angle distributions following different amounts of deformation in cold-rolled aluminum and nickel and compressed stainless steel is reported. The sealing of the dislocation cell boundary misorientation angle distributions is studied. Surprisingly, the distributions...... for the small to large strain regimes for aluminum, 304L stainless steel, nickel, and copper (taken from the literature )appear to be identical. Hence the distributions may be "universal." These results have significant implications for the development of dislocation based deformation models. [S0031...

  7. AGN jet physics and apparent opening angles

    CERN Document Server

    Clausen-Brown, Eric; Pushkarev, Alexander B; Kovalev, Yuri Y; Lister, Matthew L

    2013-01-01

    We present a new method to measure Gamma*theta_j in flux-limited samples of active galactic nuclei (AGN) jets, where Gamma is the bulk Lorentz factor and theta_j is the jet's half-opening angle. The Gamma*theta_j parameter is physically important for models of jet launching, and also determines the effectiveness of jet instabilities and magnetic reconnection. We measure Gamma*theta_j by analyzing the observed distribution of apparent opening angles in very long baseline interferometry (VLBI) flux-limited samples of jets, given some prior knowledge of the active galactic nuclei (AGN) radio luminosity function. We then apply this method to the MOJAVE flux-limited sample of radio loud objects and find Gamma*theta_j = 0.1 +- 0.03, which implies that AGN jets are subject to a variety of physical processes that require causal connection.

  8. 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.

  9. Variations of refraction angles from observations of the Moon from space.

    Science.gov (United States)

    Kireev, S V; Sokolovskiy, S V

    1994-12-20

    We present the results of measurements of optical refraction angles from photographs of the Moon taken from the orbital station Mir. We made estimations of rms fluctuations of refraction angles and of the characteristics of multipath propagation.

  10. 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

  11. 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...

  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. 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.

  15. Wide Angle Effects in Galaxy Surveys

    CERN Document Server

    Yoo, Jaiyul

    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 that compared to the sample variance, the deviation in the redshift-space correlation function from the simple Kaiser formula with the distant-observer approximation is negligible in the SDSS and is completely irrelevant in future galaxy surveys such as Euclid and the BigBOSS, if the theoretical prediction from the Kaiser formula is averaged over the survey volume and the non-uniform distribution of cosine angle between the line-of-sight and the pair separation directions is properly considered. We also find small correctio...

  16. 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

  17. Multi-angle compound imaging

    DEFF Research Database (Denmark)

    Jespersen, Søren Kragh; Wilhjelm, Jens Erik; Sillesen, Henrik

    1998-01-01

    to conventional B-mode imaging MACI offers better defined tissue boundaries and lower variance of the speckle pattern, resulting in an image with reduced random variations. Design and implementation of a compound imaging system is described, images of rubber tubes and porcine aorta are shown and effects......This paper reports on a scanning technique, denoted multi-angle compound imaging (MACI), using spatial compounding. The MACI method also contains elements of frequency compounding, as the transmit frequency is lowered for the highest beam angles in order to reduce grating lobes. Compared...... on visualization are discussed. The speckle reduction is analyzed numerically and the results are found to be in excellent agreement with existing theory. An investigation of detectability of low-contrast lesions shows significant improvements compared to conventional imaging. Finally, possibilities for improving...

  18. Optimisation of Fan Blade Angle

    Directory of Open Access Journals (Sweden)

    Swaroop M P

    2017-01-01

    Full Text Available This report represents the optimization of fan blade angle in accordance with the various room temperatures that can be in the tropical area like India. We took this work mainly because cooling is an important factor now a days in every area where construction and rooms are there and ceiling fans are the most common device that is commonly used. So it is of utmost importance to tweak the performance of this ceiling fan so that it can function in its most optimal condition. We have modeled the fan in a modeling software (SOLIDWORKS and imported that into an analyzing software (ANSYS and a result is generated on the various blade angles (0, 4, 8 and 12.5 degrees in accordance to room conditions. A trend line curve with the obtained data is expected as the result which can be crucial for designing of future fans

  19. [Determination of contact angle of pharmaceutical excipients and regulating effect of surfactants on their wettability].

    Science.gov (United States)

    Hua, Dong-dong; Li, He-ran; Yang, Bai-xue; Song, Li-na; Liu, Tiao-tiao; Cong, Yu-tang; Li, San-ming

    2015-10-01

    To study the effects of surfactants on wettability of excipients, the contact angles of six types of surfactants on the surface of two common excipients and mixture of three surfactants with excipients were measured using hypsometry method. The results demonstrated that contact angle of water on the surface of excipients was associated with hydrophilcity of excipients. Contact angle was lowered with increase in hydrophilic groups of excipient molecules. The sequence of contact angle from small to large was starch contact angle of excipients, and their abilities to lower contact angle varied. The results of the present study offer a guideline in the formulation design of tablets.

  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. Angle of arrival estimation using spectral interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Barber, Z.W.; Harrington, C.; Thiel, C.W.; Babbitt, W.R. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Krishna Mohan, R., E-mail: krishna@spectrum.montana.ed [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States)

    2010-09-15

    We have developed a correlative signal processing concept based on a Mach-Zehnder interferometer and spatial-spectral (S2) materials that enables direct mapping of RF spectral phase as well as power spectral recording. This configuration can be used for precise frequency resolved time delay estimation between signals received by a phased antenna array system that in turn could be utilized to estimate the angle of arrival. We present an analytical theoretical model and a proof-of-principle demonstration of the concept of time difference of arrival estimation with a cryogenically cooled Tm:YAG crystal that operates on microwave signals modulated onto a stabilized optical carrier at 793 nm.

  2. GEODSS Present Configuration and Potential

    Science.gov (United States)

    2014-06-28

    1. REPORT DATE 28 JUN 2014 2. REPORT TYPE 3. DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE GEODSS Present Configuration and...provides improved resolution and radiometric throughput at low elevation angles versus a single fisheye optical strategy. Both optical systems are

  3. A spin- and angle-resolving photoelectron spectrometer

    CERN Document Server

    Berntsen, M H; Leandersson, M; Hahlin, A; hlund, J \\AA; Wannberg, B; nsson, M M\\aa; Tjernberg, O

    2010-01-01

    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. Slope angle studies from multibeam sonar data on three seamounts in Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Kodagali, V.N.

    is presented here. The slope angle grid can be used to create the slope angle map. Morphology of three seamounts from Central Indian Basin and the slope angle data on them are described. The seamounts are of the heights 1000-1200 m and occupy area up to 300 sq...

  5. 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.

  6. Proper Angle of Sono-guided Central Venous Line Insertion

    Science.gov (United States)

    Barzegari, Hassan; Forouzan, Arash; Fahimi, Mohammad Ali; Zohrevandi, Behzad; Ghanavati, Mandana

    2016-01-01

    Introduction: Determining the proper angle for inserting central venous catheter (CV line) is of great importance for decreasing the complications and increasing success rate. The present study was designed to determine the proper angle of needle insertion for internal jugular vein catheterization. Methods: In the present case series study, candidate patients for catheterization of the right internal jugular vein under guidance of ultrasonography were studied. At the time of proper placing of the catheter, photograph was taken and Auto Cad 2014 software was used to measure the angles of the needle in the sagittal and axial planes, as well as patient’s head rotation. Result: 114 patients with the mean age of 56.96 ± 14.71 years were evaluated (68.4% male). The most common indications of catheterization were hemodialysis (55.3%) and shock state (24.6%). The mean angles of needle insertion were 102.15 ± 6.80 for axial plane, 36.21 ± 3.12 for sagittal plane and the mean head rotation angle was 40.49 ± 5.09. Conclusion: Based on the results of the present study it seems that CV line insertion under the angles 102.15 ± 6.80 degrees in the axial plane, 36.21 ± 3.12 in the sagittal plane and 40.49 ± 5.09 head rotation yield satisfactory results. PMID:27299146

  7. Theta angle in holographic QCD

    CERN Document Server

    Jarvinen, Matti

    2016-01-01

    V-QCD is a class of effective holographic models for QCD which fully includes the backreaction of quarks to gluon dynamics. The physics of the theta-angle and the axial anomaly can be consistently included in these models. We analyze their phase diagrams over ranges of values of the quark mass, N_f/N_c, and theta, computing observables such as the topological susceptibility and the meson masses. At small quark mass, where effective chiral Lagrangians are reliable, they agree with the predictions of V-QCD.

  8. 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.

  9. 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.

  10. Modeling contact angle hysteresis on chemically patterned and superhydrophobic surfaces.

    Science.gov (United States)

    Kusumaatmaja, H; Yeomans, J M

    2007-05-22

    We investigate contact angle hysteresis on chemically patterned and superhydrophobic surfaces, as the drop volume is quasistatically increased and decreased. We consider both two (cylindrical drops) and three (spherical drops) dimensions using analytical and numerical approaches to minimize the free energy of the drop. In two dimensions, we find, in agreement with other authors, a slip, jump, stick motion of the contact line. In three dimensions, this behavior persists, but the position and magnitude of the contact line jumps are sensitive to the details of the surface patterning. In two dimensions, we identify analytically the advancing and receding contact angles on the different surfaces, and we use numerical insights to argue that these provide bounds for the three-dimensional cases. We present explicit simulations to show that a simple average over the disorder is not sufficient to predict the details of the contact angle hysteresis and to support an explanation for the low contact angle hysteresis of suspended drops on superhydrophobic surfaces.

  11. Can dynamic contact angle be measured using molecular modeling?

    Science.gov (United States)

    Malani, Ateeque; Raghavanpillai, Anilkumar; Wysong, Ernest B; Rutledge, Gregory C

    2012-11-02

    A method is presented for determining the dynamic contact angle at the three-phase contact between a solid, a liquid, and a vapor under an applied force, using molecular simulation. The method is demonstrated using a Lennard-Jones fluid in contact with a cylindrical shell of the fcc Lennard-Jones solid. Advancing and receding contact angles and the contact angle hysteresis are reported for the first time by this approach. The increase in force required to wet fully an array of solid cylinders (robustness) with decreasing separation distance between cylinders is evaluated. The dynamic contact angle is characterized by partial slipping of the three phase contact line when a force is applied.

  12. Determination of the position angle of stellar spin axes

    CERN Document Server

    Lesage, Anna-Lea

    2014-01-01

    Measuring the stellar position angle provides valuable information on binary stellar formation or stellar spin axis evolution. We aim to develop a method for determining the absolute stellar position angle using spectro-astrometric analysis of high resolution long-slit spectra. The method has been designed in particular for slowly rotating stars. We investigate its applicability to existing dispersive long-slit spectrographs, identified here by their plate scale, and the size of the resulting stellar sample. The stellar rotation induces a tilt in the stellar lines whose angle depends on the stellar position angle and the orientation of the slit. We developed a rotation model to calculate and reproduce the effects of stellar rotation on unreduced high resolution stellar spectra. Then we retrieved the tilt amplitude using a spectro-astrometric extraction of the position of the photocentre of the spectrum. Finally we present two methods for analysing the position spectrum using either direct measurement of the t...

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    -sets. These features of the investigated sonic anemometers make them unsuitable for measuring vertical velocities over highly turbulent forested terrain. By comparing the sonic anemometer results to that of a conically scanning Doppler lidar (Dellwik et al., 2010b), sonic anemometer accuracy for measuring mean flow...... distortion and vertical alignment, it was only possible to a limited extent to relate sonic anemometer flow tilt angles to upwind forest edges, but the results by the lidar indicated that an internal boundary layer affect flow tilt angles at 21m above the forest. This is in accordance with earlier studies......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...

  14. Aerial wetting contact angle measurement using confocal microscopy

    Science.gov (United States)

    Chesna, Jacob W.; Wiedmaier, Bob F.; Wang, Jinlin; Samara, Ayman; Leach, Richard K.; Her, Tsing-Hua; Smith, Stuart T.

    2016-12-01

    A method is presented in which the wetting contact angle of a sessile drop is acquired aerially using confocal techniques to measure the radius and the height of a droplet deposited on a planar surface. The repeatability of this method is typically less than 0.25°, and often less than 0.1°, for droplet diameters less than 1 mm. To evaluate accuracy of this method, an instrument uncertainty budget is developed, which predicts a combined uncertainty of 0.91° for a 1 mm diameter water droplet with a contact angle of 110°. For droplets having diameters less than 1 mm and contact angles between 15° and 160°, these droplets approach spherical shape and their contact angles can be computed analytically with less than 1% error. For larger droplets, gravitational deformation needs to be considered.

  15. 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

  16. An efficient magic state approach to small angle rotations

    Science.gov (United States)

    Campbell, Earl T.; O'Gorman, Joe

    2016-12-01

    Standard error-correction techniques only provide a quantum memory and need extra gadgets to perform computation. Central to quantum algorithms are small angle rotations, which can be fault-tolerantly implemented given a supply of an unconventional species of magic state. We present a low-cost distillation routine for preparing these small angle magic states. Our protocol builds on the work of Duclos-Cianci and Poulin (2015 Phys. Rev. A 91 042315) by compressing their circuit. Additionally, we present a method of diluting magic states that reduces costs associated with very small angle rotations. We quantify performance by the expected number of noisy magic states consumed per rotation, and compare with other protocols. For modest-sized angles, our protocols offer a factor 24 improvement over the best-known gate synthesis protocols and a factor 2 over the Duclos-Cianci and Poulin protocol. For very small angle rotations, the dilution protocol dramatically reduces costs, giving several orders magnitude improvement over competitors. There also exists an intermediary regime of small, but not very small, angles where our approach gives a marginal improvement over gate synthesis. We discuss how different performance metrics may alter these conclusions.

  17. A Universal Formula for Extracting the Euler Angles

    Science.gov (United States)

    Shuster, Malcolm D.; Markley, F. Landis

    2004-01-01

    Recently, the authors completed a study of the Davenport angles, which are a generalization of the Euler angles for which the initial and final Euler axes need not be either mutually parallel or mutually perpendicular or even along the coordinate axes. During the conduct of that study, those authors discovered a relationship which can be used to compute straightforwardly the Euler angles characterizing a proper-orthogonal direction-cosine matrix for an arbitrary Euler-axis set satisfying n(sub 1) x n(sub 2) = 0 and n(sub 3) x n(sub 1) = 0, which is also satisfied by the more usual Euler angles we encounter commonly in the practice of Astronautics. Rather than leave that relationship hidden in an article with very different focus from the present Engineering note, we present it and the universal algorithm derived from it for extracting the Euler angles from the direction-cosine matrix here. We also offer literal "code" for performing the operations, numerical examples, and general considerations about the extraction of Euler angles which are not universally known, particularly, the treatment of statistical error.

  18. Static and dynamic contact angles of water droplet on a solid surface using molecular dynamics simulation.

    Science.gov (United States)

    Hong, Seung Do; Ha, Man Yeong; Balachandar, S

    2009-11-01

    The present study investigates the variation of static contact angle of a water droplet in equilibrium with a solid surface in the absence of a body force and the dynamic contact angles of water droplet moving on a solid surface for different characteristic energies using the molecular dynamics simulation. With increasing characteristic energy, the static contact angle in equilibrium with a solid surface in the absence of a body force decreases because the hydrophobic surface changes its characteristics to the hydrophilic surface. In order to consider the effect of moving water droplet on the dynamic contact angles, we apply the constant acceleration to an individual oxygen and hydrogen atom. In the presence of a body force, the water droplet changes its shape with larger advancing contact angle than the receding angle. The dynamic contact angles are compared with the static contact angle in order to see the effect of the presence of a body force.

  19. 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.

  20. Impact on Spin Tune From Horizontal Orbital Angle Between Snakes and Orbital Angle Between Spin Rotators

    Energy Technology Data Exchange (ETDEWEB)

    Bai,M.; Ptitsyn, V.; Roser, T.

    2008-10-01

    To keep the spin tune in the spin depolarizing resonance free region is required for accelerating polarized protons to high energy. In RHIC, two snakes are located at the opposite side of each accelerator. They are configured to yield a spin tune of 1/2. Two pairs of spin rotators are located at either side of two detectors in each ring in RHIC to provide longitudinal polarization for the experiments. Since the spin rotation from vertical to longitudinal is localized between the two rotators, the spin rotators do not change the spin tune. However, due to the imperfection of the orbits around the snakes and rotators, the spin tune can be shifted. This note presents the impact of the horizontal orbital angle between the two snakes on the spin tune, as well as the effect of the vertical orbital angle between two rotators at either side of the collision point on the spin tune.

  1. 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...

  2. 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...

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

    OpenAIRE

    Van Damme; 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 presented in which contact-angle hysteresis of PAMA's is explained in terms of the reorientation of polymer chains and segments at the interface of the polymers with water and air. The contact angles obser...

  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. Individualized optimal release angles in discus throwing.

    Science.gov (United States)

    Leigh, Steve; Liu, Hui; Hubbard, Mont; Yu, Bing

    2010-02-10

    The purpose of this study was to determine individualized optimal release angles for elite discus throwers. Three-dimensional coordinate data were obtained for at least 10 competitive trials for each subject. Regression relationships between release speed and release angle, and between aerodynamic distance and release angle were determined for each subject. These relationships were linear with subject-specific characteristics. The subject-specific relationships between release speed and release angle may be due to subjects' technical and physical characteristics. The subject-specific relationships between aerodynamic distance and release angle may be due to interactions between the release angle, the angle of attack, and the aerodynamic distance. Optimal release angles were estimated for each subject using the regression relationships and equations of projectile motion. The estimated optimal release angle was different for different subjects, and ranged from 35 degrees to 44 degrees . The results of this study demonstrate that the optimal release angle for discus throwing is thrower-specific. The release angles used by elite discus throwers in competition are not necessarily optimal for all discus throwers, or even themselves. The results of this study provide significant information for understanding the biomechanics of discus throwing techniques.

  6. Transcription and the Pitch Angle of DNA

    CERN Document Server

    Olsen, Kasper W

    2013-01-01

    The question of the value of the pitch angle of DNA is visited from the perspective of a geometrical analysis of transcription. It is suggested that for transcription to be possible, the pitch angle of B-DNA must be smaller than the angle of zero-twist. At the zero-twist angle the double helix is maximally rotated and its strain-twist coupling vanishes. A numerical estimate of the pitch angle for B-DNA based on differential geometry is compared with numbers obtained from existing empirical data. The crystallographic studies shows that the pitch angle is approximately 38 deg., less than the corresponding zero-twist angle of 41.8 deg., which is consistent with the suggested principle for transcription.

  7. 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.

  8. Equilibrium contact angles of liquid droplets on ideal rough solids.

    Science.gov (United States)

    Kang, Hie Chan; Jacobi, Anthony M

    2011-12-20

    This work proposes a theoretical model for predicting the apparent equilibrium contact angle of a liquid on an ideal rough surface that is homogeneous and has a negligible body force, line tension, or contact angle hysteresis between solid and liquid. The model is derived from the conservation equations and the free-energy minimization theory for the changes of state of liquid droplets. The work of adhesion is expressed as the contact angles in the wetting process of the liquid droplets. Equilibrium contact angles of liquid droplets for rough surfaces are expressed as functions of the area ratios for the solid, liquid, and surrounding gas and the roughness ratio and wetting ratio of the liquid on the solid for the partially and fully wet states. It is found that the ideal critical angle for accentuating the contact angles by the surface roughness is 48°. The present model is compared with existing experimental data and the classical Wenzel and Cassie-Baxter models and agrees with most of the experimental data for various surfaces and liquids better than does the Wenzel model and accounts for trends that the Wenzel model cannot explain.

  9. Measuring static and dynamic contact angles using a liquid needle

    Science.gov (United States)

    Sanedrin, Raymond; Jin, Ming; Frese, Daniel; Scheithauer, Carsten; Willers, Thomas

    2016-11-01

    The optical determination of static and advancing contact angle is made on drops applied or extended, respectively, onto a substrate through the use of thin solid needles. Although this method has been used extensively, this method of dosing can be time consuming, cumbersome and if not meticulously performed can lead to erroneous contact angle results. Herein, we present an alternative way of applying drops onto substrates using a small liquid jet, which is produced by a liquid pressure dosing system acting as a "liquid needle." A comparative static contact angle study on 14 different surfaces with two different liquids were performed utilizing two different ways of dosing: the conventional solid and a novel liquid needle based technique. We found, for all but one sample, that the obtained results were highly comparable. Observed differences can be explained by the characteristics of either way of dosing. In addition, we used the liquid pressure based dosing system for optical advancing contact angle measurement on two different samples. The liquid needle based method facilitates the expansion of a drop from 0.1 to 22 μL within less than 1.2 seconds, which provided constant contact angle versus drop base diameter curves. The obtained results were highly comparable with dynamic Wilhelmy contact angle measurements.

  10. 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.

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

    Science.gov (United States)

    Li, Qing; Luo, K. H.; Kang, Q. J.; Chen, Q.

    2014-11-01

    In this paper we investigate the implementation of contact angles in the pseudopotential lattice Boltzmann modeling of wetting at a large density ratio ρL/ρV=500 . The pseudopotential lattice Boltzmann model [X. Shan and H. Chen, Phys. Rev. E 49, 2941 (1994), 10.1103/PhysRevE.49.2941] 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 θ static contact angles close to 180∘. Meanwhile, it is found that the proposed modified pseudopotential-based interaction performs better in light of the maximum and the minimum densities and is overall more suitable for simulating large contact angles θ >90∘ as compared with the two other types of fluid-solid interactions. Furthermore, the spurious currents are found to be enlarged when the fluid-solid interaction force is introduced. Increasing the kinematic viscosity ratio between the vapor and liquid phases is shown to be capable of reducing the spurious currents caused by the fluid-solid interactions.

  12. The Influence of Dynamic Contact Angle on Wetting Dynamics

    Science.gov (United States)

    Rame, Enrique; Garoff, Steven

    2005-01-01

    When surface tension forces dominate, and regardless of whether the situation is static or dynamic, the contact angle (the angle the interface between two immiscible fluids makes when it contacts a solid) is the key parameter that determines the shape of a fluid-fluid interface. The static contact angle is easy to measure and implement in models predicting static capillary surface shapes and such associated quantities as pressure drops. By contrast, when the interface moves relative to the solid (as in dynamic wetting processes) the dynamic contact angle is not identified unambiguously because it depends on the geometry of the system Consequently, its determination becomes problematic and measurements in one geometry cannot be applied in another for prediction purposes. However, knowing how to measure and use the dynamic contact angle is crucial to determine such dynamics as a microsystem throughput reliably. In this talk we will present experimental and analytical efforts aimed at resolving modeling issues present in dynamic wetting. We will review experiments that show the inadequacy of the usual hydrodynamic model when a fluid-fluid meniscus moves over a solid surface such as the wall of a small tube or duct. We will then present analytical results that show how to parametrize these problems in a predictive manner. We will illustrate these ideas by showing how to implement the method in numerical fluid mechanical calculations.

  13. 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.

  14. Dynamic contact angle measurements on superhydrophobic surfaces

    Science.gov (United States)

    Kim, Jeong-Hyun; Kavehpour, H. Pirouz; Rothstein, Jonathan P.

    2015-03-01

    In this paper, the dynamic advancing and receding contact angles of a series of aqueous solutions were measured on a number of hydrophobic and superhydrophobic surfaces using a modified Wilhelmy plate technique. Superhydrophobic surfaces are hydrophobic surfaces with micron or nanometer sized surface roughness. These surfaces have very large static advancing contact angles and little static contact angle hysteresis. In this study, the dynamic advancing and dynamic receding contact angles on superhydrophobic surfaces were measured as a function of plate velocity and capillary number. The dynamic contact angles measured on a smooth hydrophobic Teflon surface were found to obey the scaling with capillary number predicted by the Cox-Voinov-Tanner law, θD3 ∝ Ca. The response of the dynamic contact angle on the superhydrophobic surfaces, however, did not follow the same scaling law. The advancing contact angle was found to remain constant at θA = 160∘, independent of capillary number. The dynamic receding contact angle measurements on superhydrophobic surfaces were found to decrease with increasing capillary number; however, the presence of slip on the superhydrophobic surface was found to result in a shift in the onset of dynamic contact angle variation to larger capillary numbers. In addition, a much weaker dependence of the dynamic contact angle on capillary number was observed for some of the superhydrophobic surfaces tested.

  15. 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.

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

    DEFF Research Database (Denmark)

    Dellwik, Ebba; Mann, Jakob; Bingöl, Ferhat

    2010-01-01

    ) 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...... vertical velocity, whereas the error due to flow inhomogeneity on the horizontal mean wind speed is independent of the lidar beam angle. For the presented measurements over forest, it is evaluated that the systematic error due to the inhomogeneity of the flow is less than 0.2°. The results of the vertical...... conical scans were promising, and yielded positive flow angles for a sector where the forest is fetch-limited. However, more data and analysis are needed for a complete evaluation of the lidar technique....

  17. 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.

  18. Contact angle measurements under thermodynamic equilibrium conditions.

    Science.gov (United States)

    Lages, Carol; Méndez, Eduardo

    2007-08-01

    The precise control of the ambient humidity during contact angle measurements is needed to obtain stable and valid data. For a such purpose, a simple low-cost device was designed, and several modified surfaces relevant to biosensor design were studied. Static contact angle values for these surfaces are lower than advancing contact angles published for ambient conditions, indicating that thermodynamic equilibrium conditions are needed to avoid drop evaporation during the measurements.

  19. Distinguishing features of shallow angle plunging jets

    Science.gov (United States)

    Deshpande, Suraj S.; Trujillo, Mario F.

    2013-08-01

    Numerical simulations employing an algebraic volume-of-fluid methodology are used to study the air entrainment characteristics of a water jet plunging into a quiescent water pool at angles ranging from θ = 10° to θ = 90° measured from the horizontal. Our previous study of shallow angled jets [S. S. Deshpande, M. F. Trujillo, X. Wu, and G. L. Chahine, "Computational and experimental characterization of a liquid jet plunging into a quiescent pool at shallow inclination," Int. J. Heat Fluid Flow 34, 1-14 (2012)], 10.1016/j.ijheatfluidflow.2012.01.011 revealed the existence of a clearly discernible frequency of ingestion of large air cavities. This is in contrast with chaotic entrainment of small air pockets reported in the literature in case of steeper or vertically plunging jets. In the present work, the differences are addressed by first quantifying the cavity size and entrained air volumes for different impingement angles. The results support the expected trend - reduction in cavity size (D43) as θ is increased. Time histories of cavity volumes in the vicinity of the impingement region confirm the visual observations pertaining to a near-periodic ingestion of large air volumes for shallow jets (10°, 12°), and also show that such cavities are not formed for steep or vertical jets. Each large cavity (defined as Dc/Dj ≳ 3) exists in close association with a stagnation point flow. A local mass and momentum balance shows that the high stagnation pressure causes a radial redirection of the jet, resulting in a flow that resembles the initial impact of a jet on the pool. In fact, for these large cavities, their speed matches closely Uimpact/2, which coincides with initial cavity propagation for sufficiently high Froude numbers. Furthermore, it is shown that the approximate periodicity of air entrainment scales linearly with Froude number. This finding is confirmed by a number of simulations at θ = 12°. Qualitatively, for steeper jets, such large stagnation

  20. 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)

  1. Contact angle hysteresis of a drop spreading over metal surfaces

    Directory of Open Access Journals (Sweden)

    Kuznetsov Geniy

    2016-01-01

    Full Text Available The paper presents experimental data on the contact angle hysteresis of the distilled water drop spreading over the surfaces of non-ferrous metals. The measurements of the advancing and receding contact angles were carried out by method of sitting drop on the horizontal surface during increasing and decreasing drop volume with a syringe pump. It was found that the contact line speed has a great influence on the hysteresis of the polished non-elastic substrates. The mechanism of spreading was described using the balance of the forces from the physical point of view.

  2. Static contact angle in lattice Boltzmann models of immiscible fluids.

    Science.gov (United States)

    Latva-Kokko, M; Rothman, Daniel H

    2005-10-01

    We study numerically the capillary rise between two horizontal plates and in a rectangular tube, using a lattice Boltzmann (LB) method. We derive an equation for the static fluid-solid contact angle as a function of the wetting tendency of the walls and test its validity. We show that the generalized Laplace law with two independent radii of curvature is followed in capillary rise in rectangular tubes. Our method removes the history dependence of the fluid-solid contact angle that had been present in earlier LB schemes.

  3. 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.

  4. 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…

  5. Contact angle hysteresis on fluoropolymer surfaces.

    Science.gov (United States)

    Tavana, H; Jehnichen, D; Grundke, K; Hair, M L; Neumann, A W

    2007-10-31

    Contact angle hysteresis of liquids with different molecular and geometrical properties on high quality films of four fluoropolymers was studied. A number of different causes are identified for hysteresis. With n-alkanes as probe liquids, contact angle hysteresis is found to be strongly related to the configuration of polymer chains. The largest hysteresis is obtained with amorphous polymers whereas the smallest hysteresis occurs for polymers with ordered molecular chains. This is explained in terms of sorption of liquid by the solid and penetration of liquid into the polymer film. Correlation of contact angle hysteresis with the size of n-alkane molecules supports this conclusion. On the films of two amorphous fluoropolymers with different molecular configurations, contact angle hysteresis of one and the same liquid with "bulky" molecules is shown to be quite different. On the surfaces of Teflon AF 1600, with stiff molecular chains, the receding angles of the probe liquids are independent of contact time between solid and liquid and similar hysteresis is obtained for all the liquids. Retention of liquid molecules on the solid surface is proposed as the most likely cause of hysteresis in these systems. On the other hand, with EGC-1700 films that consist of flexible chains, the receding angles are strongly time-dependent and the hysteresis is large. Contact angle hysteresis increases even further when liquids with strong dipolar intermolecular forces are used. In this case, major reorganization of EGC-1700 chains due to contact with the test liquids is suggested as the cause. The effect of rate of motion of the three-phase line on the advancing and receding contact angles, and therefore contact angle hysteresis, is investigated. For low viscous liquids, contact angles are independent of the drop front velocity up to approximately 10 mm/min. This agrees with the results of an earlier study that showed that the rate-dependence of the contact angles is an issue only

  6. 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.

  7. Modeling liquid bridge between surfaces with contact angle hysteresis.

    Science.gov (United States)

    Chen, H; Amirfazli, A; Tang, T

    2013-03-12

    This paper presents the behaviors of a liquid bridge when being compressed and stretched in a quasi-static fashion between two solid surfaces that have contact angle hysteresis (CAH). A theoretical model is developed to obtain the profiles of the liquid bridge given a specific separation between the surfaces. Different from previous models, both contact lines in the upper and lower surfaces were allowed to move when the contact angles reach their advancing or receding values. When the contact angles are between their advancing and receding values, the contact lines are pinned while the contact angles adjust to accommodate the changes in separation. Effects of CAH on both asymmetric and symmetric liquid bridges were analyzed. The model was shown to be able to correctly predict the behavior of the liquid bridge during a quasi-static compression/stretching loading cycle in experiments. Because of CAH, the liquid bridge can have two different profiles at the same separation during one loading and unloading cycle, and more profiles can be obtained during multiple cycles. The maximum adhesion force generated by the liquid bridge is found to be influenced by the CAH of surfaces. CAH also leads to energy cost during a loading cycle of the liquid bridge. In addition, the minimum separation between the two solid surfaces is shown to affect how the contact radii and angles change on the two surfaces as the liquid bridge is stretched.

  8. 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.

  9. 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...

  10. 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...

  11. Automated measurement of diagnostic angles for hip dysplasia

    DEFF Research Database (Denmark)

    de Raedt, Sepp; Mechlenburg, I.; Stilling, M.

    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...

  12. 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.

  13. 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.

  14. Automatic cobb angle determination from radiographic images

    NARCIS (Netherlands)

    Sardjono, Tri Arief; Wilkinson, Michael H.F.; Veldhuizen, Albert G.; Ooijen, van Peter M.A.; Purnama, Ketut E.; Verkerke, Gijsbertus J.

    2013-01-01

    Study Design. Automatic measurement of Cobb angle in patients with scoliosis. Objective. To test the accuracy of an automatic Cobb angle determination method from frontal radiographical images. Summary of Background Data. Thirty-six frontal radiographical images of patients with scoliosis. Met

  15. Automatic Cobb Angle Determination From Radiographic Images

    NARCIS (Netherlands)

    Sardjono, Tri Arief; Wilkinson, Michael H. F.; Veldhuizen, Albert G.; van Ooijen, Peter M. A.; Purnama, Ketut E.; Verkerke, Gijsbertus J.

    2013-01-01

    Study Design. Automatic measurement of Cobb angle in patients with scoliosis. Objective. To test the accuracy of an automatic Cobb angle determination method from frontal radiographical images. Summary of Background Data. Thirty-six frontal radiographical images of patients with scoliosis. Methods.

  16. Apparent contact angle and contact angle hysteresis on liquid infused surfaces.

    Science.gov (United States)

    Semprebon, Ciro; McHale, Glen; Kusumaatmaja, Halim

    2016-12-21

    We theoretically investigate the apparent contact angle and contact angle hysteresis of a droplet placed on a liquid infused surface. We show that the apparent contact angle is not uniquely defined by material parameters, but also has a dependence on the relative size between the droplet and its surrounding wetting ridge formed by the infusing liquid. We derive a closed form expression for the contact angle in the limit of vanishing wetting ridge, and compute the correction for small but finite ridge, which corresponds to an effective line tension term. We also predict contact angle hysteresis on liquid infused surfaces generated by the pinning of the contact lines by the surface corrugations. Our analytical expressions for both the apparent contact angle and contact angle hysteresis can be interpreted as 'weighted sums' between the contact angles of the infusing liquid relative to the droplet and surrounding gas phases, where the weighting coefficients are given by ratios of the fluid surface tensions.

  17. Apparent contact angle and contact angle hysteresis on liquid infused surfaces

    Science.gov (United States)

    Semprebon, Ciro; McHale, Glen; Kusumaatmaja, Halim

    We theoretically investigate the apparent contact angle and contact angle hysteresis of a droplet placed on a liquid infused surface. We show that the apparent contact angle is not uniquely defined by material parameters, but also has a strong dependence on the relative size between the droplet and its surrounding wetting ridge formed by the infusing liquid. We derive a closed form expression for the contact angle in the limit of vanishing wetting ridge, and compute the correction for small but finite ridge, which corresponds to an effective line tension term. We also predict contact angle hysteresis on liquid infused surfaces generated by the pinning of the contact lines by the surface corrugations. Our analytical expressions for both the apparent contact angle and contact angle hysteresis can be interpreted as `weighted sums' between the contact angles of the infusing liquid relative to the droplet and surrounding gas phases, where the weighting coefficients are given by ratios of the fluid surface tensions.

  18. 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

  19. Reliable measurement of the receding contact angle.

    Science.gov (United States)

    Korhonen, Juuso T; Huhtamäki, Tommi; Ikkala, Olli; Ras, Robin H A

    2013-03-26

    Surface wettability is usually evaluated by the contact angle between the perimeter of a water drop and the surface. However, this single measurement is not enough for proper characterization, and the so-called advancing and receding contact angles also need to be measured. Measuring the receding contact angle can be challenging, especially for extremely hydrophobic surfaces. We demonstrate a reliable procedure by using the common needle-in-the-sessile-drop method. Generally, the contact line movement needs to be followed, and true receding movement has to be distinguished from "pseudo-movement" occurring before the receding angle is reached. Depending on the contact angle hysteresis, the initial size of the drop may need to be surprisingly large to achieve a reliable result. Although our motivation for this work was the characterization of superhydrophobic surfaces, we also show that this method works universally ranging from hydrophilic to superhydrophobic surfaces.

  20. Nanodrop contact angles from molecular dynamics simulations

    Science.gov (United States)

    Ravipati, Srikanth; Aymard, Benjamin; Yatsyshin, Petr; Galindo, Amparo; Kalliadasis, Serafim

    2016-11-01

    The contact angle between three phases being in thermodynamic equilibrium is highly sensitive to the nature of the intermolecular forces as well as to various fluctuation effects. Determining the Young contact angle of a sessile drop sitting on a substrate from molecular dynamics (MD) simulations is a highly non-trivial task. Most commonly employed methods for finding droplet contact angles from MD simulation data either require large numbers of particles or are system-dependent. We propose a systematic geometry based methodology for extracting the contact angle from simulated sessile droplets by analysing an appropriately coarse-grained density field. To demonstrate the method, we consider Lennard-Jones (LJ) and SPC/E water nanodroplets of different sizes sitting on planar LJ walls. Our results are in good agreement with Young contact angle values computed employing test-area perturbation method.

  1. Apparent contact angle and contact angle hysteresis on liquid infused surfaces

    OpenAIRE

    Semprebon, Ciro; McHale, Glen; Kusumaatmaja, Halim

    2017-01-01

    We theoretically investigate the apparent contact angle and contact angle hysteresis of a droplet placed on a liquid infused surface. We show that the apparent contact angle is not uniquely defined by material parameters, but also has a strong dependence on the relative size between the droplet and its surrounding wetting ridge formed by the infusing liquid. We derive a closed form expression for the contact angle in the limit of vanishing wetting ridge, and compute the correction for small b...

  2. 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.

  3. Estimation of bearing contact angle in-situ by X-ray kinematography

    Science.gov (United States)

    Fowler, P. H.; Manders, F.

    1982-01-01

    The mounted, preloaded contact angle of the structural bearings in the assembled design mechanical assembly was measured. A modification of the Turns method is presented, based upon the clarity and definition of moving parts achieved with X-ray technique and cinematic display. Contact angle is estimated by counting the number of bearings passing a given point as a function of number of turns of the shaft. Ball and pitch diameter variations are discussed. Ball train and shaft angle uncertainties are also discussed.

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

    OpenAIRE

    Sejdić Ervin; Hung Delbert; Steele Catriona M; Chau Tom

    2009-01-01

    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 c...

  5. 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.

  6. Observations of nonthermal plasmas at different aspect angles

    OpenAIRE

    Winser, K. J.; Lockwood, Mike; G. O. L. Jones; Suvanto, K.

    1989-01-01

    Data are presented from the EISCAT (European Incoherent Scatter (Facility)) CP-3-E experiment which show large increases in the auroral zone convection velocities (>2 km s−1) over a wide range of latitudes. These are larger than the estimated neutral thermal speed and allow a study of the plasma in a nonthermal state over a range of observing angles. Spectra are presented which show a well-defined central peak, consistent with an ion velocity distribution function which significantly departs ...

  7. Conservative compensatory Angle Class III malocclusion treatment

    Directory of Open Access Journals (Sweden)

    Marcio Costa Sobral

    2012-12-01

    Full Text Available INTRODUCTION: Angle's Class III malocclusion is a dental discrepancy in a sagittal view that may appear or not with an important skeletal discrepancy. Facial esthetics may be affected by this skeletal discrepancy and it is one of the most common complaints of patients who seek orthodontic treatment. Class III treatment, in adults, may be done by compensatory tooth movement, in simple cases, or through an association between orthodontics and orthognathic surgery, in more severe cases. OBJECTIVE: This article describes a non-extraction compensatory Class III treatment case, applying the Tweed-Merrifield mechanical principles with headgear (J-Hook in the mandibular arch. This case was presented at the V Brazilian Association of Orthodontics and Dentofacial Orthopedics (ABOR Meeting, it was evaluated by members of Brazilian Board of Orthodontics and obtained third place in the general classification.INTRODUÇÃO: a má oclusão de Classe III se caracteriza por uma desarmonia dentária anteroposterior, podendo estar ou não acompanhada por discrepâncias esqueléticas. A estética facial pode se apresentar comprometida, em maior ou menor grau, a depender da magnitude da discrepância, constituindo um dos principais fatores motivadores da procura por tratamento ortodôntico. O tratamento da Classe III em pacientes adultos pode ser realizado mediante compensação dentária, nos casos mais simples, ou, em situações mais severas, mediante a associação entre Ortodontia e Cirurgia Ortognática. OBJETIVO: o presente artigo objetiva relatar um caso clínico caracterizado por uma má oclusão de Classe III de Angle, tratado de forma compensatória, com extração dos terceiros molares inferiores, mediante a utilização de aparelhagem extrabucal na arcada inferior (J-hook, aplicando-se princípios da técnica de Tweed-Merrifield. Esse caso foi apresentado no 5º Congresso da Associação Brasileira de Ortodontia e Ortopedia Facial (ABOR, na categoria

  8. 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

  9. Determination of the position angle of stellar spin axes

    Science.gov (United States)

    Lesage, A.-L.; Wiedemann, G.

    2014-03-01

    Context. Measuring the stellar position angle provides valuable information on binary stellar formation or stellar spin axis evolution. Aims: We aim to develop a method for determining the absolute stellar position angle using spectro-astrometric analysis of high resolution long-slit spectra. The method has been designed in particular for slowly rotating stars. We investigate its applicability to existing dispersive long-slit spectrographs, identified here by their plate scale, and the size of the resulting stellar sample. Methods: The stellar rotation induces a tilt in the stellar lines whose angle depends on the stellar position angle and the orientation of the slit. We developed a rotation model to calculate and reproduce the effects of stellar rotation on unreduced high resolution stellar spectra. Then we retrieved the tilt amplitude using a spectro-astrometric extraction of the position of the photocentre of the spectrum. Finally we present two methods for analysing the position spectrum using either direct measurement of the tilt or a cross-correlation analysis. Results: For stars with large apparent diameter and using a spectrograph with a small plate scale, we show that it is possible to determine the stellar position angle directly within 10° with a signal-to-noise ratio of the order of 6. Under less favourable conditions, i.e. larger plate scale or smaller stellar diameter, the cross-correlation method yields comparable results. Conclusions: We show that with the currently existing instruments, it is possible to determine the stellar position angle of at least 50 stars precisely, mostly K-type giants with apparent diameter down to 5 milliarcseconds. If we consider errors of around 10° still acceptable, we may include stars with apparent diameter down to 2 mas in the sample that then comprises also some main sequence stars.

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

    Science.gov (United States)

    Li, Qing; Luo, K H; Kang, Q J; Chen, Q

    2014-11-01

    In this paper we investigate the implementation of contact angles in the pseudopotential lattice Boltzmann modeling of wetting at a large density ratio ρ_{L}/ρ_{V}=500. The pseudopotential lattice Boltzmann model [X. Shan and H. Chen, Phys. Rev. E 49, 2941 (1994)10.1103/PhysRevE.49.2941] 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 θstatic contact angles close to 180^{∘}. Meanwhile, it is found that the proposed modified pseudopotential-based interaction performs better in light of the maximum and the minimum densities and is overall more suitable for simulating large contact angles θ>90^{∘} as compared with the two other types of fluid-solid interactions. Furthermore, the spurious currents are found to be enlarged when the fluid-solid interaction force is introduced. Increasing the kinematic viscosity ratio between the vapor and liquid phases is shown to be capable of reducing the spurious currents caused by the fluid-solid interactions.

  11. Polarization properties of retroreflecting right-angle prisms.

    Science.gov (United States)

    Azzam, R M A; Khanfar, H K

    2008-01-20

    The cumulative retardance Delta(t) introduced between the p and the s orthogonal linear polarizations after two successive total internal reflections (TIRs) inside a right-angle prism at complementary angles phi and 90 degrees - phi is calculated as a function of phi and prism refractive index n. Quarter-wave retardation (QWR) is obtained on retroreflection with minimum angular sensitivity when n=(sqr rt 2+1)(1/2)=1.55377 and phi =45 degrees. A QWR prism made of N-BAK4 Schott glass (n=1.55377 at lambda=1303.5 nm) has good spectral response (<5 degrees retardance error) over the 0.5-2 microm visible and near-IR spectral range. A ZnS-coated right-angle Si prism achieves QWR with an error of < +/- 2.5 degrees in the 9-11 microm (CO(2) laser) IR spectral range. This device functions as a linear-to-circular polarization transformer and can be tuned to exact QWR at any desired wavelength (within a given range) by tilting the prism by a small angle around phi =45 degrees. A PbTe right-angle prism introduces near-half-wave retardation (near-HWR) with a < or =2% error over a broad (4< or =lambda< or =12.5 microm) IR spectral range. This device also has a wide field of view and its interesting polarization properties are discussed. A compact (aspect ratio of 2), in-line, HWR is described that uses a chevron dual Fresnel rhomb with four TIRs at the same angle phi =45 degrees. Finally, a useful algorithm is presented that transforms a three-term Sellmeier dispersion relation of a transparent optical material to an equivalent cubic equation that can be solved for the wavelengths at which the refractive index assumes any desired value.

  12. 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.

  13. Intermittent acute angle closure glaucoma and chronic angle closure following topiramate use with plateau iris configuration

    Directory of Open Access Journals (Sweden)

    Rajjoub LZ

    2014-07-01

    Full Text Available Lamise Z Rajjoub, Nisha Chadha, David A Belyea Department of Ophthalmology, The George Washington University, Washington, DC, USA Abstract: This is a case report describing recurrent intermittent acute angle closure episodes in the setting of topiramate use in a female suffering from migraines. Despite laser peripheral iridotomy placement for the pupillary block component, and the discontinuation of topiramate, the acute angle closure did not resolve in the left eye with chronic angle closure and the patient required urgent trabeculectomy. The right eye responded to laser peripheral iridotomy immediately and further improved after the cessation of topiramate. While secondary angle closure glaucoma due to topiramate use has been widely reported, its effects in patients with underlying primary angle closure glaucoma have not been discussed. Our report highlights the importance of recognizing the often multifactorial etiology of angle closure glaucoma to help guide clinical management. Keywords: angle closure glaucoma, plateau iris, topiramate, secondary glaucoma, drug-induced glaucoma

  14. 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.

  15. Blind Source Separation in Farsi Language by Using Hermitian Angle in Convolutive Enviroment

    Directory of Open Access Journals (Sweden)

    Atefeh Soltani

    2013-04-01

    Full Text Available This paper presents a T-F masking method for convolutive blind source separation based on hermitian angle concept. The hermitian angle is calculated between T-F domain mixture vector and reference vector. Two different reference vectors are assumed for calculating two different hermitian angles, and then these angles are clustered with k-means or FCM method to estimate unmixing masks. The well-known permutation problem is solved based on k-means clustering of estimated masks which are partitioned to small groups. The experimental results show an improvement in performance when using two different reference vectors compared to only one.

  16. Small angle diffraction imaging for disease diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Wilkinson, S.J. [Department of Materials and Medical Sciences, Cranfield University, Shrivenham, Swindon, Wiltshire SN6 8LA (United Kingdom)]. E-mail: s.j.wilkinson@dl.ac.uk; Rogers, K.D. [Department of Materials and Medical Sciences, Cranfield University, Shrivenham, Swindon, Wiltshire SN6 8LA (United Kingdom); Hall, C.J. [Darebury Research Laboratory, Keckwick Lane, Warrington, Cheshire, WA4 4AD (United Kingdom); Lewis, R.A. [Monash University, Melbourne, Victoria (Australia); Round, A. [Darebury Research Laboratory, Keckwick Lane, Warrington, Cheshire, WA4 4AD (United Kingdom); Pinder, S.E. [Nottingham City Hospital, Nottingham (United Kingdom); Boggis, C. [Withington Hospital, Manchester (United Kingdom); Hufton, A. [Christie Hospital, Manchester (United Kingdom)

    2005-08-11

    Current work in small angle X-ray scattering (SAXS) as a means of determining the disease state of tissue biopsy samples is showing encouraging results. Statistical analyses of SAXS patterns have identified components of the data which correlate well with the presence or absence of cancer in breast tissue. A study has now been started which attempts to create images of macroscopic scale samples using this information. One way of building up a two-dimensional map of this SAXS information on such a sample would be to raster scan a small X-ray beam. However, the time taken to perform such a scan is likely to make this technique impractical, especially if it would be considered for use in a clinical environment. Some initial work using a wide, thin X-ray beam, has shown that it is possible to deconvolve a model SAXS pattern from the smeared out SAXS pattern and is verified using slightly modified methods. Three distinct tissue types were successfully distinguished and imaged from a single scan of the beam. We are continuing this work by building a more sophisticated phantom and using a higher quality SAXS facility on the SRS in the UK. The results of the first steps towards disease specific imaging are presented. The possibility of making tomographic SAXS images is also being pursued. Techniques for data analysis on SAXS from blocks of tissues are discussed.

  17. Small angle diffraction imaging for disease diagnosis

    Science.gov (United States)

    Wilkinson, S. J.; Rogers, K. D.; Hall, C. J.; Lewis, R. A.; Round, A.; Pinder, S. E.; Boggis, C.; Hufton, A.

    2005-08-01

    Current work in small angle X-ray scattering (SAXS) as a means of determining the disease state of tissue biopsy samples is showing encouraging results. Statistical analyses of SAXS patterns have identified components of the data which correlate well with the presence or absence of cancer in breast tissue. A study has now been started which attempts to create images of macroscopic scale samples using this information. One way of building up a two-dimensional map of this SAXS information on such a sample would be to raster scan a small X-ray beam. However, the time taken to perform such a scan is likely to make this technique impractical, especially if it would be considered for use in a clinical environment. Some initial work using a wide, thin X-ray beam, has shown that it is possible to deconvolve a model SAXS pattern from the smeared out SAXS pattern and is verified using slightly modified methods. Three distinct tissue types were successfully distinguished and imaged from a single scan of the beam. We are continuing this work by building a more sophisticated phantom and using a higher quality SAXS facility on the SRS in the UK. The results of the first steps towards disease specific imaging are presented. The possibility of making tomographic SAXS images is also being pursued. Techniques for data analysis on SAXS from blocks of tissues are discussed.

  18. 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...

  19. Note: High precision angle generator using multiple ultrasonic motors and a self-calibratable encoder

    Science.gov (United States)

    Kim, Jong-Ahn; Kim, Jae Wan; Kang, Chu-Shik; Jin, Jonghan; Bong Eom, Tae

    2011-11-01

    We present an angle generator with high resolution and accuracy, which uses multiple ultrasonic motors and a self-calibratable encoder. A cylindrical air bearing guides a rotational motion, and the ultrasonic motors achieve high resolution over the full circle range with a simple configuration. The self-calibratable encoder can compensate the scale error of a divided circle (signal period: 20″) effectively by applying the equal-division-averaged method. The angle generator configures a position feedback control loop using the readout of the encoder. By combining the ac and dc operation mode, the angle generator produced stepwise angular motion with 0.005″ resolution. We also evaluated the performance of the angle generator using a precision angle encoder and an autocollimator. The expanded uncertainty (k = 2) in the angle generation was estimated less than 0.03″, which included the calibrated scale error and the nonlinearity error.

  20. Unerupted lower third molars and their influence on fractures of the mandibular angle and condyle.

    Science.gov (United States)

    Patil, Pavan M

    2012-07-01

    Our aim was to assess the influence of the presence and state of impaction of mandibular third molars on the incidence of fractures of the mandibular angle and condyle. We designed a retrospective study of patients who presented for the treatment of mandibular fractures from January 2006 to April 2011. The independent variables were the presence and degree of impaction of lower third molars, and the outcome variables were the incidence of fractures of the mandibular angle and condyle. The information was acquired from hospital records and panoramic radiographs. Personal data included age, sex, mechanism of injuries, and number of fractures of the mandibular angle and condyle. We studied 110 fractures of the mandibular condyle and 80 of the angle. The incidence of fractures of the mandibular angle was higher in the group with incompletely erupted third molars (37/80, pthird molar reduces the risk of condylar fractures and increases the risk of fractures of the mandibular angle.

  1. Contact Angle Adjustment in Equation of States Based Pseudo-Potential Model

    CERN Document Server

    Hu, Anjie; Uddin, Rizwan

    2015-01-01

    Single component pseudo-potential lattice Boltzmann model has been widely applied in multiphase simulation due to its simplicity and stability. In many research, 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 present work show that, by applying the 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 the new...

  2. 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.

  3. Nanofluid surface wettability through asymptotic contact angle.

    Science.gov (United States)

    Vafaei, Saeid; Wen, Dongsheng; Borca-Tasciuc, Theodorian

    2011-03-15

    This investigation introduces the asymptotic contact angle as a criterion to quantify the surface wettability of nanofluids and determines the variation of solid surface tensions with nanofluid concentration and nanoparticle size. The asymptotic contact angle, which is only a function of gas-liquid-solid physical properties, is independent of droplet size for ideal surfaces and can be obtained by equating the normal component of interfacial force on an axisymmetric droplet to that of a spherical droplet. The technique is illustrated for a series of bismuth telluride nanofluids where the variation of surface wettability is measured and evaluated by asymptotic contact angles as a function of nanoparticle size, concentration, and substrate material. It is found that the variation of nanofluid concentration, nanoparticle size, and substrate modifies both the gas-liquid and solid surface tensions, which consequently affects the force balance at the triple line, the contact angle, and surface wettability.

  4. 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...

  5. Apparent and Actual Dynamic Contact Angles in Confined Two-Phase Flows

    Science.gov (United States)

    Omori, Takeshi; Kajishima, Takeo

    2016-11-01

    To accurately predict the fluid flow with moving contact lines, it has a crucial importance to use a model for the dynamic contact angle which gives contact angles on the length scale corresponding to the spacial resolution of the fluid solver. The angle which a moving fluid interface forms to a solid surface deviates from an actual (microscopic) dynamic contact angle depending on the distance from the contact line and should be called an apparent (macroscopic) dynamic contact angle. They were, however, often undistinguished especially in the experimental works, on which a number of empirical correlations between a contact angle and a contact line velocity have been proposed. The present study is the first attempt to measure both apparent and actual contact angles from the identical data sets to discuss the difference and the relationship between these two contact angles of difference length scales. The study is conducted by means of numerical simulation, solving the Navier-Stokes equation and the Cahn-Hilliard equation under the generalized Navier boundary condition for the immiscible two-phase flow in channels. The present study also illustrates how the system size and the physical properties of the adjoining fluid affect the apparent and the actual dynamic contact angles. JSPS KAKENHI Grant No. 15K17974.

  6. Contact angle hysteresis on superhydrophobic stripes.

    Science.gov (United States)

    Dubov, Alexander L; Mourran, Ahmed; Möller, Martin; Vinogradova, Olga I

    2014-08-21

    We study experimentally and discuss quantitatively the contact angle hysteresis on striped superhydrophobic surfaces as a function of a solid fraction, ϕS. It is shown that the receding regime is determined by a longitudinal sliding motion of the deformed contact line. Despite an anisotropy of the texture the receding contact angle remains isotropic, i.e., is practically the same in the longitudinal and transverse directions. The cosine of the receding angle grows nonlinearly with ϕS. To interpret this we develop a theoretical model, which shows that the value of the receding angle depends both on weak defects at smooth solid areas and on the strong defects due to the elastic energy of the deformed contact line, which scales as ϕS(2)lnϕS. The advancing contact angle was found to be anisotropic, except in a dilute regime, and its value is shown to be determined by the rolling motion of the drop. The cosine of the longitudinal advancing angle depends linearly on ϕS, but a satisfactory fit to the data can only be provided if we generalize the Cassie equation to account for weak defects. The cosine of the transverse advancing angle is much smaller and is maximized at ϕS ≃ 0.5. An explanation of its value can be obtained if we invoke an additional energy due to strong defects in this direction, which is shown to be caused by the adhesion of the drop on solid sectors and is proportional to ϕS(2). Finally, the contact angle hysteresis is found to be quite large and generally anisotropic, but it becomes isotropic when ϕS ≤ 0.2.

  7. A microscopic view on contact angle selection

    OpenAIRE

    Snoeijer, Jacco H.; Andreotti, Bruno

    2008-01-01

    We discuss the equilibrium condition for a liquid that partially wets a solid on the level of intermolecular forces. Using a mean field continuum description, we generalize the capillary pressure from variation of the free energy and show at what length scale the equilibrium contact angle is selected. After recovering Young's law for homogeneous substrates, it is shown how hysteresis of the contact angle can be incorporated in a self-consistent fashion. In all cases the liquid-vapor interface...

  8. The bifurcation diagram of drops in a sphere/plane geometry: influence of contact angle hysteresis

    NARCIS (Netherlands)

    Ruiter, de Riëlle; Gorcum, van M.; Semprebon, C.; Duits, M.H.G.; Brinkmann, M.; Mugele, F.

    2014-01-01

    We study liquid drops that are present in a generic geometry, namely the gap in between a sphere and a plane. For the ideal system without contact angle hysteresis, the drop position is solely dependent on the contact angle, drop volume, and sphere/ plane separation distance. Performing a geometric

  9. The Study of the Pupil's Cognitive Structure: The Concept of Angle

    Science.gov (United States)

    Casas-Garcia, Luis M.; Luengo-Gonzalez, Ricardo

    2013-01-01

    The present research approached a problem which has a twofold aspect: the concept of angle and the techniques needed to represent how pupils construct that concept in their cognitive structure during their years in school. In order to access the knowledge of the concept of angle, we used the pathfinder associative networks. This technique provided…

  10. 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…

  11. Pressure dependence of the contact angle.

    Science.gov (United States)

    Wu, Jiyu; Farouk, T; Ward, C A

    2007-06-07

    When a liquid and its vapor contact a smooth, homogeneous surface, Gibbsian thermodynamics indicates that the contact angle depends on the pressure at the three-phase line of an isothermal system. When a recently proposed adsorption isotherm for a solid-vapor interface is combined with the equilibrium conditions and the system is assumed to be in a cylinder where the liquid-vapor interface can be approximated as spherical, the contact-angle-pressure relation can be made explicit. It indicates that a range of contact angles can be observed on a smooth homogeneous surface by changing the pressure at the three-phase line, but it also indicates that the adsorption at the solid-liquid interface is negative, and leads to the prediction that the contact angle increases with pressure. The predicted dependence of the contact angle on pressure is investigated experimentally in a system that has an independent mechanism for determining when thermodynamic equilibrium is reached. The predictions are in agreement with the measurements. The results provide a possible explanation for contact angle hysteresis.

  12. 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.

  13. Angles-only relative navigation in highly elliptical orbits

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-jia; CUI Nai-gang

    2010-01-01

    For angles-only relative navigation system only measures line-of-sight information,there are inherent problems in the ability to determine the range between Chaser and Target.Angles-only relative navigation is an at tractive alternative for inspecting or rendezvous with noncooperative target,if adequate accuracy can be achieved.Angles-only relative navigation model considering J2 perturbation is presented for tracking and rendezvous with nonco operative target in highly elliptical orbit.Impulsive out-of-plane maneuvers of the Chaser axe used to improve the navigation accuracy.The frrst impulse burns in cross-track directions to change the orbit inclination of the Chaser.The second impulse burns after one orbit period to change the orbit of the Chaser back.The simulation results show that the relative navigation system without maneuvers can' t correct the initial state errors,while impulsive out-of plane maneuvers of the Chaser improves the navigation accuracy.Angles-only relative navigation with chaser vehicle maneuvers to improve observability is effective when the spacecrafts are in highly elliptical orbits.

  14. View angle dependence of cloud optical thicknesses retrieved by MODIS

    Science.gov (United States)

    Marshak, Alexander; Varnai, Tamas

    2005-01-01

    This study examines whether cloud inhomogeneity influences the view angle dependence of MODIS cloud optical thickness (tau) retrieval results. The degree of cloud inhomogeneity is characterized through the local gradient in 11 microns brightness temperature. The analysis of liquid phase clouds in a one year long global dataset of Collection 4 MODIS data reveals that while optical thickness retrievals give remarkably consistent results for all view directions if clouds are homogeneous, they give much higher tau-values for oblique views than for overhead views if clouds are inhomogeneous and the sun is fairly oblique. For solar zenith angles larger than 55deg, the mean optical thickness retrieved for the most inhomogeneous third of cloudy pixels is more than 30% higher for oblique views than for overhead views. After considering a variety of possible scenarios, the paper concludes that the most likely reason for the increase lies in three-dimensional radiative interactions that are not considered in current, one-dimensional retrieval algorithms. Namely, the radiative effect of cloud sides viewed at oblique angles seems to contribute most to the enhanced tau-values. The results presented here will help understand cloud retrieval uncertainties related to cloud inhomogeneity. They complement the uncertainty estimates that will start accompanying MODIS cloud products in Collection 5 and may eventually help correct for the observed view angle dependent biases.

  15. 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.

  16. 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°.

  17. 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.

  18. IMU-based joint angle measurement for gait analysis.

    Science.gov (United States)

    Seel, Thomas; Raisch, Jörg; Schauer, Thomas

    2014-04-16

    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°.

  19. Contact angle hysteresis: study by dynamic cycling contact angle measurements and variable angle spectroscopic ellipsometry on polyimide.

    Science.gov (United States)

    Hennig, A; Eichhorn, K-J; Staudinger, U; Sahre, K; Rogalli, M; Stamm, M; Neumann, A W; Grundke, K

    2004-08-03

    The phenomenon of contact angle hysteresis was studied on smooth films of polyimide, a polymer type used in the microelectronic industry, by dynamic cycling contact angle measurements based on axisymmetric drop shape analysis-profile in combination with variable angle spectroscopic ellipsometry (VASE). It was found that both advancing and receding contact angles became smaller with increasing the number of cycles and are, therefore, not a property of the dry solid alone. The changes of the wetting behavior during these dynamic cycling contact angle measurements are attributed mainly to swelling and/or liquid retention. To reveal the water-induced changes of the polymer film, the polyimide surface was studied before and after the contact with a water droplet by VASE. Both the experimental ellipsometric spectrum for Delta and that for Psi as well as the corresponding simulations show characteristic shifts due to the contact with water. The so-called effective medium approximation was applied to recover information about the thickness and effective optical constants of the polymer layer from the ellipsometrically measured values of Delta and Psi. On the basis of these results, the swelling and retention behavior of the polyimide films in contact with water droplets were discussed.

  20. 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.

  1. Starting position of movement and perception of angle of trunk flexion while standing with eyes closed.

    Science.gov (United States)

    Fujiwara, K; Miyaguchi, A; Toyama, H; Kunita, K; Asai, H

    1999-08-01

    The present study attempted to investigate the effect of position on the perception of angle of trunk flexion while standing. For this purpose, the range effect was factored out by setting the constant target angle at 10 degrees, with varied starting positions of trunk flexion. We found that subjects underestimated angle of trunk flexion when the starting position was close to a quiet standing posture, overestimated when close to maximum trunk flexion, and correctly perceived it when at the middle position. Less perceptual distortion was observed at the positions close to maximum trunk flexion in the present study than in our previous one, in which various target angles of trunk flexion were reproduced from a quiet standing posture. The reduced distortion in the present study was believed to have resulted from factoring out the range effect. The flexion angle of the hip joint changed in tandem with that of the trunk, while very little movement was observed in the ankle, knee, and neck joints. Judging from the changing pattern of hip-joint angle, the muscle activity of the erector spinae and biceps femoris increased gradually to 90 degrees trunk flexion. In contrast, the actual increment of muscle activity reached zero or a minimum value at the middle angles as the angle of trunk flexion increased. It was assumed that the abrupt change in kinesthetic information associated with muscle activity exerted a great influence on the perception of trunk flexion.

  2. 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.

  3. 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.

  4. The CTS 11.7 GHz angle of arrival experiment

    Science.gov (United States)

    Kwan, B. W.; Hodge, D. B.

    1981-01-01

    The objective of the experiment was to determine the statistical behavior of attenuation and angle of arrival on an Earth-space propagation path using the CTS 11.7 GHz beacon. Measurements performed from 1976 to 1978 form the data base for analysis. The statistics of the signal attenuation and phase variations due to atmospheric disturbances are presented. Rainfall rate distributions are also included to provide a link between the above effects on wave propagation and meteorological conditions.

  5. Continuous separation of submicron particles using Angled electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Yunus, Nurul A Md; Green, Nicolas G [Nano Research Group, School of Electronics and Computer Science, University of Southampton, SO17 1BJ (United Kingdom)], E-mail: ng2@ecs.soton.ac.uk

    2008-12-01

    Dielectrophoretic separation of particles is achieved by the generation of electric forces on the particles by non-uniform electric fields. This paper presents a technique based on negative dielectrophoresis in a novel design of electrode array for the non-contact separation of polarisable particles. Angled electrodes are used to generate a lateral force in a microfluidic channel separating a mixed stream of particles into distinct streams of constituent components and achieving a high degree of spatial separation.

  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. 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.

  8. Algorithm for automatic angles measurement and screening for Developmental Dysplasia of the Hip (DDH).

    Science.gov (United States)

    Al-Bashir, Areen K; Al-Abed, Mohammad; Abu Sharkh, Fayez M; Kordeya, Mohamed N; Rousan, Fadi M

    2015-01-01

    Developmental Dysplasia of the Hip (DDH) is a medical term represent the hip joint instability that appear mainly in infants. The examination for this condition can be done by ultrasound for children under 6 months old and by X-ray for children over 6 months old. Physician's assessment is based on certain angles derived from those images, namely the Acetabular Angle, and the Center Edge Angle. In this paper, we are presenting a novel, fully automatic algorithm for measuring the diagnostic angles of DDH from the X-ray images. Our algorithm consists of Automatic segmentation and extraction of anatomical landmarks from X-ray images. Both of Acetabular angle and Center edge angle are automatically calculated. The analysis included X-ray images for 16 children recruited for the purposed of this study. The automatically acquired angles accuracy for Acetabular Angle was around 85%, and an absolute deviation of 3.4°±3.3° compared to the physician's manually calculated angle. The results of this method are very promising for the future development of an automatic method for screening X-ray images DDH that complement and aid the physicians' manual methods.

  9. Anterior Chamber Angle Shape Analysis and Classification of Glaucoma in SS-OCT Images

    Directory of Open Access Journals (Sweden)

    Soe Ni Ni

    2014-01-01

    Full Text Available Optical coherence tomography is a high resolution, rapid, and noninvasive diagnostic tool for angle closure glaucoma. In this paper, we present a new strategy for the classification of the angle closure glaucoma using morphological shape analysis of the iridocorneal angle. The angle structure configuration is quantified by the following six features: (1 mean of the continuous measurement of the angle opening distance; (2 area of the trapezoidal profile of the iridocorneal angle centered at Schwalbe's line; (3 mean of the iris curvature from the extracted iris image; (4 complex shape descriptor, fractal dimension, to quantify the complexity, or changes of iridocorneal angle; (5 ellipticity moment shape descriptor; and (6 triangularity moment shape descriptor. Then, the fuzzy k nearest neighbor (fkNN classifier is utilized for classification of angle closure glaucoma. Two hundred and sixty-four swept source optical coherence tomography (SS-OCT images from 148 patients were analyzed in this study. From the experimental results, the fkNN reveals the best classification accuracy (99.11±0.76% and AUC (0.98±0.012 with the combination of fractal dimension and biometric parameters. It showed that the proposed approach has promising potential to become a computer aided diagnostic tool for angle closure glaucoma (ACG disease.

  10. Pre and post operative facial angles in patients submitted to rhinoplasty

    Directory of Open Access Journals (Sweden)

    Soccol, Andréa T

    2008-09-01

    Full Text Available Introduction: Parameters used in facial aesthetic surgeries are currently based on POWELL and HUMPHREYS (1. These authors have formulated suitable relations between the face and the nose, and defined the face angles. Objective: To compare pre and pos-operative nasolabial, nasofrontal, nasomental and nasofacial angles in patients submitted to rhinoseptoplasty. Method: Prospective analysis of 37 patients submitted to rhinoplasty, with an average of 30±11 years of age, being 13 (36% men and 24 (64% women. The nasolabial, nasofrontal, nasomental and nasofacial angles were measured and compared, before and after the surgery, in profile pictures. Results: An average increase of 8.6o in the nasolabial angle was observed, of 8.5o in the nasofrontal and reduction of 2.3o in the nasofacial angle, and all the measures presented a statistically significant difference between the pre and pos-operative period. The nasomental angle increased, on average, 1.6o, a difference without statistical importance. Conclusions: The nasolabial and nasofrontal angles increase significantly after rhinoseptoplasty, while the nasofacial angle diminishes. There was no significant alteration in the nasomental angle with the accomplishment of the surgery.

  11. Detailed statistical contact angle analyses; "slow moving" drops on inclining silicon-oxide surfaces.

    Science.gov (United States)

    Schmitt, M; Groß, K; Grub, J; Heib, F

    2015-06-01

    Contact angle determination by sessile drop technique is essential to characterise surface properties in science and in industry. Different specific angles can be observed on every solid which are correlated with the advancing or the receding of the triple line. Different procedures and definitions for the determination of specific angles exist which are often not comprehensible or reproducible. Therefore one of the most important things in this area is to build standard, reproducible and valid methods for determining advancing/receding contact angles. This contribution introduces novel techniques to analyse dynamic contact angle measurements (sessile drop) in detail which are applicable for axisymmetric and non-axisymmetric drops. Not only the recently presented fit solution by sigmoid function and the independent analysis of the different parameters (inclination, contact angle, velocity of the triple point) but also the dependent analysis will be firstly explained in detail. These approaches lead to contact angle data and different access on specific contact angles which are independent from "user-skills" and subjectivity of the operator. As example the motion behaviour of droplets on flat silicon-oxide surfaces after different surface treatments is dynamically measured by sessile drop technique when inclining the sample plate. The triple points, the inclination angles, the downhill (advancing motion) and the uphill angles (receding motion) obtained by high-precision drop shape analysis are independently and dependently statistically analysed. Due to the small covered distance for the dependent analysis (static to the "slow moving" dynamic contact angle determination. They are characterised by small deviations of the computed values. Additional to the detailed introduction of this novel analytical approaches plus fit solution special motion relations for the drop on inclined surfaces and detailed relations about the reactivity of the freshly cleaned silicon wafer

  12. 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.

  13. Three paths toward the quantum angle operator

    Science.gov (United States)

    Gazeau, Jean Pierre; Szafraniec, Franciszek Hugon

    2016-12-01

    We examine mathematical questions around angle (or phase) operator associated with a number operator through a short list of basic requirements. We implement three methods of construction of quantum angle. The first one is based on operator theory and parallels the definition of angle for the upper half-circle through its cosine and completed by a sign inversion. The two other methods are integral quantization generalizing in a certain sense the Berezin-Klauder approaches. One method pertains to Weyl-Heisenberg integral quantization of the plane viewed as the phase space of the motion on the line. It depends on a family of "weight" functions on the plane. The third method rests upon coherent state quantization of the cylinder viewed as the phase space of the motion on the circle. The construction of these coherent states depends on a family of probability distributions on the line.

  14. Tunable contact angle hysteresis on micropatterned surfaces

    CERN Document Server

    Debuisson, Damien; Arscott, Steve

    2011-01-01

    Micropatterned surfaces composed of concentric circular defects having a smooth trench-like profile are formed using a photoresist (SU-8). When an evaporating droplet encounters the micropatterned surface an evaporation phase is observed consisting of distinct discontinuities and steps in the droplet wetting contact angle and base radius respectively. The addition of gaps into the circular defects enables tuning of the contact angle hysteresis; the receding contact angle of fluorocarbon coated SU-8 can be tuned between 34.6{\\deg} and 89.1{\\deg} and that of SU-8 surfaces from 5.6{\\deg} to 43.3{\\deg} depending on the gap length. In addition, a model is developed which accurately predicts the observed behavior.

  15. Michelson interferometer for precision angle measurement.

    Science.gov (United States)

    Ikram, M; Hussain, G

    1999-01-01

    An angle-measuring technique based on an optical interferometer is reported. The technique exploits a Michelson interferometric configuration in which a right-angle prism and a glass strip are introduced into a probe beam. Simultaneous rotation of both components along an axis results in an optical path difference between the reference and the probe beams. In a second arrangement two right-angle prisms and glass strips are introduced into two beams of a Michelson interferometer. The prisms and the strips are rotated simultaneously to introduce an optical path difference between the two beams. In our arrangement, optimization of various parameters makes the net optical path difference between the two beams approximately linear for a rotation as great as +/-20 degrees . Results are simulated that show an improvement of 2-3 orders of magnitude in error and nonlinearity compared with a previously reported technique.

  16. Magic-angle thermal desorption mass spectroscopy

    Science.gov (United States)

    Pauls, Steven W.; Campbell, Charles T.

    1990-02-01

    Accurate quantitative measurements of desorption rates or adsorbate coverages in thermal desorption mass spectroscopy (TDS) using line-of-sight mass spectrometers are hindered by the fact that the angular distributions of desorption flux can vary widely from desorbate to desorbate, ranging from cos 1ø to cos 9 ø for most species studied to date (ø = polar angle from surface normal). These differences can easily lead to errors exceeding 400% in measuring the relative desorption rates of different species. We show here that, by placing the mass spectrometer's ion source or entrance aperture at a "magic-angle" ø mthese errors can be reduced to less than 26% maximum deviation (or ± 7% standard deviation). Depending upon the sample-to-detector distance, ø m varies from ~ 42° to 34°. It is recommended that TDS experiments be performed at this "magic-angle" for improvement in the quantitative accuracy of coverage or rate measurements.

  17. Weak lensing using only galaxy position angles

    CERN Document Server

    Whittaker, Lee; Battye, Richard

    2013-01-01

    We develop a method for performing a weak lensing analysis using only measurements of galaxy position angles. By analyzing the statistical properties of the galaxy orientations given a known intrinsic ellipticity distribution, we show that it is possible to obtain estimates of the shear by minimizing a $\\chi^2$ statistic. The method is demonstrated using simulations where the components of the intrinsic ellipticity are taken to be Gaussian distributed. Uncertainties on the position angle measurements introduce a bias into the shear estimates which can be reduced to negligible levels by introducing a correction term into the formalism. We generalize our approach by developing an algorithm to obtain direct shear estimators given any azimuthally symmetric intrinsic ellipticity distribution. We demonstrate this technique by applying it to simulations where the ellipticities are taken to follow a log-normal distribution. We compare the performance of the position angle only method with the standard method based on...

  18. 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.

  19. Head flexion angle while using a smartphone.

    Science.gov (United States)

    Lee, Sojeong; Kang, Hwayeong; Shin, Gwanseob

    2015-01-01

    Repetitive or prolonged head flexion posture while using a smartphone is known as one of risk factors for pain symptoms in the neck. To quantitatively assess the amount and range of head flexion of smartphone users, head forward flexion angle was measured from 18 participants when they were conducing three common smartphone tasks (text messaging, web browsing, video watching) while sitting and standing in a laboratory setting. It was found that participants maintained head flexion of 33-45° (50th percentile angle) from vertical when using the smartphone. The head flexion angle was significantly larger (p neck pain of heavy smartphone users. Practitioner Summary: In this laboratory study, the severity of head flexion of smartphone users was quantitatively evaluated when conducting text messaging, web browsing and video watching while sitting and standing. Study results indicate that text messaging while sitting caused the largest head flexion than that of other task conditions.

  20. 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.

  1. Methodology for high accuracy contact angle measurement.

    Science.gov (United States)

    Kalantarian, A; David, R; Neumann, A W

    2009-12-15

    A new version of axisymmetric drop shape analysis (ADSA) called ADSA-NA (ADSA-no apex) was developed for measuring interfacial properties for drop configurations without an apex. ADSA-NA facilitates contact angle measurements on drops with a capillary protruding into the drop. Thus a much simpler experimental setup, not involving formation of a complete drop from below through a hole in the test surface, may be used. The contact angles of long-chained alkanes on a commercial fluoropolymer, Teflon AF 1600, were measured using the new method. A new numerical scheme was incorporated into the image processing to improve the location of the contact points of the liquid meniscus with the solid substrate to subpixel resolution. The images acquired in the experiments were also analyzed by a different drop shape technique called theoretical image fitting analysis-axisymmetric interfaces (TIFA-AI). The results were compared with literature values obtained by means of the standard ADSA for sessile drops with the apex. Comparison of the results from ADSA-NA with those from TIFA-AI and ADSA reveals that, with different numerical strategies and experimental setups, contact angles can be measured with an accuracy of less than 0.2 degrees. Contact angles and surface tensions measured from drops with no apex, i.e., by means of ADSA-NA and TIFA-AI, were considerably less scattered than those from complete drops with apex. ADSA-NA was also used to explore sources of improvement in contact angle resolution. It was found that using an accurate value of surface tension as an input enhances the accuracy of contact angle measurements.

  2. 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.

  3. Angle-Resolved Spectroscopy of Parametric Fluorescence

    CERN Document Server

    Hsu, Feng-kuo

    2013-01-01

    The parametric fluorescence from a nonlinear crystal forms a conical radiation pattern. We measure the angular and spectral distributions of parametric fluorescence in a beta-barium borate crystal pumped by a 405-nm diode laser employing angle-resolved imaging spectroscopy. The experimental angle-resolved spectra and the generation efficiency of parametric down conversion are compared with a plane-wave theoretical analysis. The parametric fluorescence is used as a broadband light source for the calibration of the instrument spectral response function in the wavelength range from 450 to 1000 nm.

  4. 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.

  5. Understanding Angle and Angle Measure: A Design-Based Research Study Using Context Aware Ubiquitous Learning

    Science.gov (United States)

    Crompton, Helen

    2015-01-01

    Mobile technologies are quickly becoming tools found in the educational environment. The researchers in this study use a form of mobile learning to support students in learning about angle concepts. Design-based research is used in this study to develop an empirically-substantiated local instruction theory about students' develop of angle and…

  6. Abstract Presentations: What Do SGIM Presenters Prefer?

    OpenAIRE

    Tulsky, Asher A.; Kouides, Ruth W

    1998-01-01

    We surveyed physicians presenting abstracts at the 1995 Society of General Internal Medicine annual meeting to determine whether the oral or poster format better achieved their presentation goals. Poster presentations better met respondents' objectives for feedback and criticism and for networking and developing collaborative projects, while oral presentations better met their objectives for national visibility and sharing knowledge within one's field. Sixty-nine percent of respondents prefer...

  7. 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...

  8. 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.

  9. 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.

  10. Bilateral simultaneous acute angle closure caused by sulphonamide derivatives: A case series

    Directory of Open Access Journals (Sweden)

    Senthil Sirisha

    2010-01-01

    Full Text Available The sulphonamide group of drugs is implicated in bilateral acute angle closure (AAC due to an idiosyncratic response. We report a series of three cases with bilateral AAC caused by different sulphonamide derivatives, their presentation and management.

  11. Bilateral simultaneous acute angle closure caused by sulphonamide derivatives: A case series

    OpenAIRE

    Senthil Sirisha; Garudadri Chandrasekhar; Rao Harsha; Maheshwari Rajat

    2010-01-01

    The sulphonamide group of drugs is implicated in bilateral acute angle closure (AAC) due to an idiosyncratic response. We report a series of three cases with bilateral AAC caused by different sulphonamide derivatives, their presentation and management.

  12. Bilateral simultaneous acute angle closure caused by sulphonamide derivatives: a case series.

    Science.gov (United States)

    Senthil, Sirisha; Garudadri, Chandrasekhar; Rao, Harsha B L; Maheshwari, Rajat

    2010-01-01

    The sulphonamide group of drugs is implicated in bilateral acute angle closure (AAC) due to an idiosyncratic response. We report a series of three cases with bilateral AAC caused by different sulphonamide derivatives, their presentation and management.

  13. 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.

  14. Performance measurement of broadband, wide-angle polarizing beam splitter

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei-bin; ZHENG Zhen-rong; GU Pei-fu; ZHANG Yue-guang

    2007-01-01

    Polarizing beam splitter (PBS) is a critical optical component in projection display system because PBS performance greatly influences the contrast and brightness of the system. PBS performance is usually measured by spectrophotometer after coating and cementing, but the measured result cannot represent the actual performance in practice because people usually change the incident angle in one plane (horizontal plane) and do not consider the other plane (vertical plane). Geometrical polarization rotation occurring at reduced F-number influences the measuring precision of s-polarization transmittance (Ts) and p-polarization reflectance (Rp). A more accurate and practical way to measure the performance of broadband, wide-angle PBS is presented in this paper.

  15. 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.

  16. 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.

  17. Incidence angle normalization of radar backscatter data

    Science.gov (United States)

    NASA’s Soil Moisture Passive Active (SMAP) satellite (~2014) will include a radar system that will provide L-band multi-polarization backscatter at a constant incidence angle of 40º. During the pre-launch phase of the project there is a need for observations that will support the radar-based soil mo...

  18. Constant Angle Surfaces in the Heisenberg Group

    Institute of Scientific and Technical Information of China (English)

    Johan FASTENAKELS; Marian Ioan MUNTEANU; Joeri VAN DER VEKEN

    2011-01-01

    In this article we extend the notion of constant angle surfaces in S2 × R and H2 × R to general Bianchi-Cartan-Vranceanu spaces. We show that these surfaces have constant Gaussian curvature and we give a complete local classification in the Heisenberg group.

  19. A thin-film magnetoresistive angle detector

    NARCIS (Netherlands)

    Eijkel, Kees J.M.; Wieberdink, Johan W.; Fluitman, Jan H.J; Popma, Theo J.A.; Groot, Peter; Leeuwis, Henk

    1990-01-01

    An overview is given of the results of our research on a contactless angle detector based on the anisotropic magnetoresistance effect (AMR effect) in a permalloy thin film. The results of high-temperature annealing treatment of the pemalloy film are discussed. Such a treatment suppresses the effects

  20. Testing CMB polarization data using position angles

    CERN Document Server

    Preece, Michael

    2014-01-01

    We consider a novel null test for contamination which can be applied to CMB polarization data that involves analysis of the statistics of the polarization position angles. Specifically, we will concentrate on using histograms of the measured position angles to illustrate the idea. Such a test has been used to identify systematics in the NVSS point source catalogue with an amplitude well below the noise level. We explore the statistical properties of polarization angles in CMB maps. If the polarization angle is not correlated between pixels, then the errors follow a simple $\\sqrt{N_{pix}}$ law. However this is typically not the case for CMB maps since these have correlations which result in an increase in the variance since the effective number of independent pixels is reduced. Then we illustrate how certain classes of systematic errors can result in very obvious patterns in these histograms, and thus that these errors could possibly be identified using this method. We discuss how this idea might be applied in...

  1. Contact Angle Effects in Boiling Heat Transfer

    OpenAIRE

    Urquiola, Erwin; Fujita, Yasunobu

    2002-01-01

    This paper reports boiling experiments with pure water and surfactant solutions of SDS on horizontal heating surface. The static contact angle, rather than the surface tension value, was found to be the leading factor for the results and probably its prev

  2. Molecular mechanisms underlying primary open angle glaucoma

    NARCIS (Netherlands)

    Janssen, S.F.

    2014-01-01

    Primary open angle glaucoma (POAG) is a complex, multigenetic and heterogeneous optic neuropathy. It is an insidious disease that untreated leads to irreversible visual field loss and blindness. Worldwide, glaucoma causes around 12% of blindness. Although various risk factors have been established,

  3. Camber Angle Inspection for Vehicle Wheel Alignments

    Science.gov (United States)

    Young, Jieh-Shian; Hsu, Hong-Yi; Chuang, Chih-Yuan

    2017-01-01

    This paper introduces an alternative approach to the camber angle measurement for vehicle wheel alignment. Instead of current commercial approaches that apply computation vision techniques, this study aims at realizing a micro-control-unit (MCU)-based camber inspection system with a 3-axis accelerometer. We analyze the precision of the inspection system for the axis misalignments of the accelerometer. The results show that the axes of the accelerometer can be aligned to the axes of the camber inspection system imperfectly. The calibrations that can amend these axis misalignments between the camber inspection system and the accelerometer are also originally proposed since misalignments will usually happen in fabrications of the inspection systems. During camber angle measurements, the x-axis or z-axis of the camber inspection system and the wheel need not be perfectly aligned in the proposed approach. We accomplished two typical authentic camber angle measurements. The results show that the proposed approach is applicable with a precision of ±0.015∘ and therefore facilitates the camber measurement process without downgrading the precision by employing an appropriate 3-axis accelerometer. In addition, the measured results of camber angles can be transmitted via the medium such as RS232, Bluetooth, and Wi-Fi. PMID:28165365

  4. Camber Angle Inspection for Vehicle Wheel Alignments

    Directory of Open Access Journals (Sweden)

    Jieh-Shian Young

    2017-02-01

    Full Text Available This paper introduces an alternative approach to the camber angle measurement for vehicle wheel alignment. Instead of current commercial approaches that apply computation vision techniques, this study aims at realizing a micro-control-unit (MCU-based camber inspection system with a 3-axis accelerometer. We analyze the precision of the inspection system for the axis misalignments of the accelerometer. The results show that the axes of the accelerometer can be aligned to the axes of the camber inspection system imperfectly. The calibrations that can amend these axis misalignments between the camber inspection system and the accelerometer are also originally proposed since misalignments will usually happen in fabrications of the inspection systems. During camber angle measurements, the x-axis or z-axis of the camber inspection system and the wheel need not be perfectly aligned in the proposed approach. We accomplished two typical authentic camber angle measurements. The results show that the proposed approach is applicable with a precision of ± 0.015 ∘ and therefore facilitates the camber measurement process without downgrading the precision by employing an appropriate 3-axis accelerometer. In addition, the measured results of camber angles can be transmitted via the medium such as RS232, Bluetooth, and Wi-Fi.

  5. An anisotropic negative refractive index medium operated at multiple-angle incidences.

    Science.gov (United States)

    Yang, Tien-Chung; Yang, Yu-Hang; Yen, Ta-Jen

    2009-12-21

    Recently metamaterials have been demonstrating new physics to enable various unprecedented electromagnetic properties, but pratically they are so sensitive to incident angles of the external excitation that their applications are restricted. Therefore, we present an anisotropic negative refractive index medium operated at multiple-angle incidences (NRIM for MAI) to ease such a burden. Both the simulated and measured transmittance, reflectance and the corresponding material parameters indicate that our structure does possess the anisotropic negative refractive index with respect to different incident angles. In addition, the opposite directions of group and phase velocities are also demonstrated under both grazing-angle, normal and 45-degree incidences to further verify the negative refractive index of the designed monolithic NRIM structure for multiple-angle incidences.

  6. Development of a body joint angle measurement system using IMU sensors.

    Science.gov (United States)

    Bakhshi, Saba; Mahoor, Mohammad H; Davidson, Bradley S

    2011-01-01

    This paper presents an approach for measuring and monitoring human body joint angles using inertial measurement unit (IMU) sensors. This type of monitoring is beneficial for therapists and physicians because it facilitates remote assessment of patient activities. In our approach, two IMUs are mounted on the upper leg and the lower leg to measure the Euler angles of each segment. The Euler angles are sent via Bluetooth protocols to a pc for calculating the knee joint angle. In our experiments, we utilized a motion capture system to accurately measure the knee joint angle and used this as the ground truth to assess the accuracy of the IMU system. The range of average error of the system across a variety of motion trials was 0.08 to 3.06 degrees. In summary, the accuracy of the IMU measurement system currently outperforms existing wearable systems such as conductive fiber optic sensors and flex-sensors.

  7. 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°.``

  8. 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.)

  9. Simulation calculation for the energy deposition profile and the transmission fraction of intense pulsed electron beam at various incident angles

    CERN Document Server

    Yang Hai Liang; Zhang Jia Sheng; Huang Jian Jun; Sun Jian Feng

    2002-01-01

    The incident angles have a heavy effect on the intense pulsed electron beam energy deposition profile, energy deposition fraction and beam current transmission fraction in material. The author presents electron beam energy deposition profile and energy deposition fraction versus electron energy (0.5-2.0 MeV), at various incident angles for three aluminum targets of various thickness via theoretical calculation. The intense pulsed electron beam current transmission fractions versus electron energy (0.4-1.4 MeV) at various incident angles for three thickness of carbon targets were also theoretically calculated. The calculation results indicate that the deposition energy in unit mass of material surface layer increase with the rise of electron beam incident angle, and electron beam with low incident angle (closer to normal incident angle) penetrates deeper into the target material. The electron beams deposit more energy in unit mass of material surface layer at 60 degree-70 degree incident angle

  10. 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

  11. 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.

  12. 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.

  13. 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°.

  14. 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.

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

    Science.gov (United States)

    Heinemann, Thomas; Palczynski, Karol; Dzubiella, Joachim; Klapp, Sabine H L

    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. Pressure Angle in Parallel Mechanisms:From Planar to Spatial

    Institute of Scientific and Technical Information of China (English)

    赵庆; 梅江平; 宋涛; 刘松涛

    2016-01-01

    This paper presents the evolution process of pressure angles from planar parallel mechanisms to spatial parallel mechanisms. Manipulability and condition number, which are frequently used in the optimum design of parallel mechanisms, are introduced from serial robots at first. Then, both theoretical analysis and practical experi-ences demonstrate that these concepts seem imperfect when they are used in parallel mechanisms. For this reason, this paper introduces the pressure angles in planar 4-bar mechanisms to spatial parallel mechanisms, which include redundant parallel mechanisms. Two kinds of pressure angles extracted from the determinant of direct and indirect Jacobian matrices are investigated. Moreover, two comprehensive and visible global performance indices are de-fined, showing the advantages in evaluating the workspace, singularity and motion/force transmission capabilities. With a 2-DOF planar and a 3-DOF spatial parallel mechanism as examples, the application of the performance indi-ces is investigated and compared with the condition number at last. The proposed concept can be extended to other spatial parallel mechanisms.

  17. 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.

  18. 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.

  19. 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 ...

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

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, K.T. (Lawrence Berkeley Lab., CA (United States) California Univ., Berkeley, CA (United States). Dept. of Chemistry)

    1991-07-01

    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.

  1. On some relations between advancing, receding and Young's contact angles.

    Science.gov (United States)

    Chibowski, Emil

    2007-05-31

    Problems of experimental determination and theoretical verification of equilibrium contact angles are discussed basing on the literature data. A relationship between the advancing and receding contact angles versus the equilibrium contact angle is described and then verified using the literature contact angles determined on paraffin wax and polypropylene. Using the proposed relationship and experimentally determined equilibrium contact angles, obtained by plotting the advancing and receding contact angles versus the contact angle hysteresis or by applying vibration of the system liquid drop/solid surface, it is found that the same value of the surface free energy for paraffin wax is calculated from the contact angles of water and ethylene glycol. However, in the case of polypropylene some inconsistency appears between the equilibrium contact angles of the probe liquid used and the calculated surface free energy. More experimental data of the equilibrium contact angle are needed to verify further the relationship.

  2. 3D reconstruction of cortical microtubules using multi-angle total internal reflection fluorescence microscopy

    Science.gov (United States)

    Jin, Luhong; Xiu, Peng; Zhou, Xiaoxu; Fan, Jiannan; Kuang, Cuifang; Liu, Xu; Xu, Yingke

    2017-01-01

    Total internal reflection fluorescence microscopy (TIRFM) has been widely used in biomedical research to visualize cellular processes near the cell surface. In this study, a novel multi-angle ring-illuminated TIRFM system, equipped with two galvo mirrors that are on conjugate plan of a 4f optical system was developed. Multi-angle TIRFM generates images with different penetration depths through the controlled variation of the incident angle of illuminating laser. We presented a method to perform three-dimensional (3-D) reconstruction of microtubules from multi-angle TIRFM images. The performance of our method was validated in simulated microtubules with variable signal-to-noise ratios (SNR) and the axial resolution and accuracy of reconstruction were evaluated in selecting different numbers of illumination angles or in different SNR conditions. In U373 cells, we reconstructed the 3-D localization of microtubules near the cell surface with high resolution using over a hundred different illumination angles. Theoretically, the presented TIRFM setup and 3-D reconstruction method can achieve 40 nm axial resolution in experimental conditions where SNR is as low as 2, with 35 different illumination angles. Moreover, our system and reconstruction method have the potential to be used in live cells to track membrane dynamics in 3-D.

  3. Contact angle and contact angle hysteresis measurements using the capillary bridge technique.

    Science.gov (United States)

    Restagno, Frédéric; Poulard, Christophe; Cohen, Céline; Vagharchakian, Laurianne; Léger, Liliane

    2009-09-15

    A new experimental technique is proposed to easily measure both advancing and receding contact angles of a liquid on a solid surface, with unprecedented accuracy. The technique is based on the analysis of the evolution of a capillary bridge formed between a liquid bath and a solid surface (which needs to be spherical) when the distance between the surface and the liquid bath is slowly varied. The feasibility of the technique is demonstrated using a low-energy perfluorinated surface with two different test liquids (water and hexadecane). A detailed description of both experimental procedures and computational modeling are given, allowing one to determine contact angle values. It is shown that the origin of the high accuracy of this technique relies on the fact that the contact angles are automatically averaged over the whole periphery of the contact. This method appears to be particularly adapted to the characterization of surfaces with very low contact angle hysteresis.

  4. 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.

  5. Absorbing angles, Steiner minimal trees, and antipodality

    CERN Document Server

    Martini, Horst; de Wet, P Oloff; 10.1007/s10957-009-9552-1

    2011-01-01

    We give a new proof that a star $\\{op_i:i=1,...,k\\}$ in a normed plane is a Steiner minimal tree of its vertices $\\{o,p_1,...,p_k\\}$ if and only if all angles formed by the edges at o are absorbing [Swanepoel, Networks \\textbf{36} (2000), 104--113]. The proof is more conceptual and simpler than the original one. We also find a new sufficient condition for higher-dimensional normed spaces to share this characterization. In particular, a star $\\{op_i: i=1,...,k\\}$ in any CL-space is a Steiner minimal tree of its vertices $\\{o,p_1,...,p_k\\}$ if and only if all angles are absorbing, which in turn holds if and only if all distances between the normalizations $\\frac{1}{\\|p_i\\|}p_i$ equal 2. CL-spaces include the mixed $\\ell_1$ and $\\ell_\\infty$ sum of finitely many copies of $R^1$.

  6. Reactor mixing angle from hybrid neutrino masses

    CERN Document Server

    Sierra, D Aristizabal

    2014-01-01

    In terms of its eigenvector decomposition, the neutrino mass matrix (in the basis where the charged lepton mass matrix is diagonal) can be understood as originating from a tribimaximal dominant structure with small deviations, as demanded by data. If neutrino masses originate from at least two different mechanisms, referred to as "hybrid neutrino masses", the experimentally observed structure naturally emerges provided one mechanism accounts for the dominant tribimaximal structure while the other is responsible for the deviations. We demonstrate the feasibility of this picture in a fairly model-independent way by using lepton-number-violating effective operators, whose structure we assume becomes dictated by an underlying $A_4$ flavor symmetry. We show that if a second mechanism is at work, the requirement of generating a reactor angle within its experimental range always fixes the solar and atmospheric angles in agreement with data, in contrast to the case where the deviations are induced by next-to-leading ...

  7. Picoliter water contact angle measurement on polymers.

    Science.gov (United States)

    Taylor, Michael; Urquhart, Andrew J; Zelzer, Mischa; Davies, Martyn C; Alexander, Morgan R

    2007-06-19

    Water contact angle measurement is the most common method for determining a material's wettability, and the sessile drop approach is the most frequently used. However, the method is generally limited to macroscopic measurements because the base diameter of the droplet is usually greater than 1 mm. Here we report for the first time on a dosing system to dispense smaller individual droplets with control of the position and investigate whether water contact angles determined from picoliter volume water droplets are comparable with those obtained from the conventional microliter volume water droplets. This investigation was conducted on a group of commonly used polymers. To demonstrate the higher spatial resolution of wettability that can be achieved using picoliter volume water droplets, the wettability of a radial plasma polymer gradient was mapped using a 250 microm interval grid.

  8. 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.

  9. Gaia: focus, straylight and basic angle

    Science.gov (United States)

    Mora, A.; Biermann, M.; Bombrun, A.; Boyadjian, 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.

    2016-07-01

    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.

  10. 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...

  11. Wireless Orbiter Hang-Angle Inclinometer System

    Science.gov (United States)

    Lucena, Angel; Perotti, Jose; Green, Eric; Byon, Jonathan; Burns, Bradley; Mata, Carlos; Randazzo, John; Blalock, Norman

    2011-01-01

    A document describes a system to reliably gather the hang-angle inclination of the orbiter. The system comprises a wireless handheld master station (which contains the main station software) and a wireless remote station (which contains the inclinometer sensors, the RF transceivers, and the remote station software). The remote station is designed to provide redundancy to the system. It includes two RF transceivers, two power-management boards, and four inclinometer sensors.

  12. 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.

  13. On accurate determination of contact angle

    Science.gov (United States)

    Concus, P.; Finn, R.

    1992-01-01

    Methods are proposed that exploit a microgravity environment to obtain highly accurate measurement of contact angle. These methods, which are based on our earlier mathematical results, do not require detailed measurement of a liquid free-surface, as they incorporate discontinuous or nearly-discontinuous behavior of the liquid bulk in certain container geometries. Physical testing is planned in the forthcoming IML-2 space flight and in related preparatory ground-based experiments.

  14. Contact angle hysteresis at the nanometer scale.

    Science.gov (United States)

    Delmas, Mathieu; Monthioux, Marc; Ondarçuhu, Thierry

    2011-04-01

    Using atomic force microscopy with nonconventional carbon tips, the pinning of a liquid contact line on individual nanometric defects was studied. This mechanism is responsible for the occurrence of the contact angle hysteresis. The presence of weak defects which do not contribute to the hysteresis is evidenced for the first time. The dissipated energy associated with strong defects is also measured down to values in the range of kT, which correspond to defect sizes in the order of 1 nm.

  15. Primary open-angle glaucoma genes

    OpenAIRE

    Fingert, J.H.

    2011-01-01

    A substantial fraction of glaucoma has a genetic basis. About 5% of primary open angle glaucoma (POAG) is currently attributed to single-gene or Mendelian forms of glaucoma (ie glaucoma caused by mutations in myocilinor optineurin). Mutations in these genes have a high likelihood of leading to glaucoma and are rarely seen in normal subjects. Other cases of POAG have a more complex genetic basis and are caused by the combined effects of many genetic and environmental risk factors, each of whic...

  16. Investigation of the Dynamic Contact Angle Using a Direct Numerical Simulation Method.

    Science.gov (United States)

    Zhu, Guangpu; Yao, Jun; Zhang, Lei; Sun, Hai; Li, Aifen; Shams, Bilal

    2016-11-15

    A large amount of residual oil, which exists as isolated oil slugs, remains trapped in reservoirs after water flooding. Numerous numerical studies are performed to investigate the fundamental flow mechanism of oil slugs to improve flooding efficiency. Dynamic contact angle models are usually introduced to simulate an accurate contact angle and meniscus displacement of oil slugs under a high capillary number. Nevertheless, in the oil slug flow simulation process, it is unnecessary to introduce the dynamic contact angle model because of a negligible change in the meniscus displacement after using the dynamic contact angle model when the capillary number is small. Therefore, a critical capillary number should be introduced to judge whether the dynamic contact model should be incorporated into simulations. In this study, a direct numerical simulation method is employed to simulate the oil slug flow in a capillary tube at the pore scale. The position of the interface between water and the oil slug is determined using the phase-field method. The capacity and accuracy of the model are validated using a classical benchmark: a dynamic capillary filling process. Then, different dynamic contact angle models and the factors that affect the dynamic contact angle are analyzed. The meniscus displacements of oil slugs with a dynamic contact angle and a static contact angle (SCA) are obtained during simulations, and the relative error between them is calculated automatically. The relative error limit has been defined to be 5%, beyond which the dynamic contact angle model needs to be incorporated into the simulation to approach the realistic displacement. Thus, the desired critical capillary number can be determined. A three-dimensional universal chart of critical capillary number, which functions as static contact angle and viscosity ratio, is given to provide a guideline for oil slug simulation. Also, a fitting formula is presented for ease of use.

  17. 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.

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

    Science.gov (United States)

    Kılıç, Bayram; İpek, Osman

    2017-02-01

    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.

  19. Contact angle determination procedure and detection of an invisible surface film

    Science.gov (United States)

    Meyer, G.; Grat, R.

    1990-01-01

    The contact angle value, i.e., the tangent angle of liquid resting on a planar solid surface, is a basic parameter which can be applied to a wide range of applications. The goal is to provide a basic understanding of the contact angle measurement technique and to present a simple illustration that can be applied as a quality control method; namely, detection of a surface contaminant which exists on a surface that appears clean to the unaided eye. The equipment and experimental procedures are detailed.

  20. Change of Dynamic Contact Angle of a Drop Spreading over Copper Surface

    Directory of Open Access Journals (Sweden)

    Feoktistov D.V.

    2015-01-01

    Full Text Available This work presents the comparison between the change of a dynamic contact angle during drop spreading over copper surfaces obtained in the experiment and calculated by using empirical correlations (Bracke et al., Jiang et al., Seebergh et al.. It is found that these correlations are applicable for the case of drop spreading over a smooth surface or over a rough surface into the low capillary number region (2.5·10−7. Dynamic contact angles obtained experimentally increase with increasing capillary number, besides it increases significantly on more rough surfaces. However the calculated values of angles do not depend on Ca.

  1. 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)

  2. 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.

  3. Constitutive modeling of contact angle hysteresis.

    Science.gov (United States)

    Vedantam, Srikanth; Panchagnula, Mahesh V

    2008-05-15

    We introduce a phase field model of wetting of surfaces by sessile drops. The theory uses a two-dimensional non-conserved phase field variable to parametrize the Gibbs free energy of the three-dimensional system. Contact line tension and contact angle hysteresis arise from the gradient term in the free energy and the kinetic coefficient respectively. A significant advantage of this approach is in the constitutive specification of hysteresis. The advancing and receding angles of a surface, the liquid-vapor interfacial energy and three-phase line tension are the only required constitutive inputs to the model. We first simulate hysteresis on a smooth chemically homogeneous surface using this theory. Next we show that it is possible to study heterogeneous surfaces whose component surfaces are themselves hysteretic. We use this theory to examine the wetting of a surface containing a circular heterogeneous island. The contact angle for this case is found to be determined solely by the material properties at the contact line in accord with recent experimental data.

  4. Dynamic contact angle cycling homogenizes heterogeneous surfaces.

    Science.gov (United States)

    Belibel, R; Barbaud, C; Mora, L

    2016-12-01

    In order to reduce restenosis, the necessity to develop the appropriate coating material of metallic stent is a challenge for biomedicine and scientific research over the past decade. Therefore, biodegradable copolymers of poly((R,S)-3,3 dimethylmalic acid) (PDMMLA) were prepared in order to develop a new coating exhibiting different custom groups in its side chain and being able to carry a drug. This material will be in direct contact with cells and blood. It consists of carboxylic acid and hexylic groups used for hydrophilic and hydrophobic character, respectively. The study of this material wettability and dynamic surface properties is of importance due to the influence of the chemistry and the potential motility of these chemical groups on cell adhesion and polymer kinetic hydrolysis. Cassie theory was used for the theoretical correction of contact angles of these chemical heterogeneous surfaces coatings. Dynamic Surface Analysis was used as practical homogenizer of chemical heterogeneous surfaces by cycling during many cycles in water. In this work, we confirmed that, unlike receding contact angle, advancing contact angle is influenced by the difference of only 10% of acidic groups (%A) in side-chain of polymers. It linearly decreases with increasing acidity percentage. Hysteresis (H) is also a sensitive parameter which is discussed in this paper. Finally, we conclude that cycling provides real information, thus avoiding theoretical Cassie correction. H(10)is the most sensible parameter to %A.

  5. The Brewster angle effect in SAR polarimetry

    Science.gov (United States)

    Chapman, B.

    1993-01-01

    For the double bounce case, where the radar signal is reflected twice before returning to the radar antenna, some polarization effects may be observed related to the dielectric constant of the two surfaces causing the reflections. The most noticeable effect would be that the returned signal would be preferentially H polarized. In fact, it may be possible to discern the Brewster angle for both surfaces. The locations of the Brewster angle will depend on the dielectric constant and permittivity of each surface. If it is assumed that both reflections are in the same plane of incidence, and that both surfaces are smooth and flat, there is a straightforward relationship between the degree of linear polarization m and both the dielectric constants of the two reflecting surfaces and the angle of incidence of the illuminating wave: m carat = cos 2(arccot (square root of (R(sub v) / R(sub h)))) where R(sub v,h) are the V and H polarized Fresnel reflection coefficients for two surfaces perpendicular to each other. The degree of linear polarization may be calculated from AIRSAR compressed Stokes data and compared with the given equation. The degree of linear polarization may also be calculated using tree models and compared with AIRSAR data. With further work, it may be possible to use the degree of linear polarization to determine surface parameters of certain imaged areas.

  6. Protein Amyloidogenesis Investigated by Small Angle Scattering.

    Science.gov (United States)

    Ricci, Caterina; Spinozzi, Francesco; Mariani, Paolo; Ortore, Maria Grazia

    2016-01-01

    In the last decades, the study of the mechanisms inducing amyloid fibril formation has involved several experimental and theoretical biophysical approaches. Many efforts have been made by scientist at the borderline between biology, chemistry, biochemistry and physics in order to understand why and in which way a protein starts its amyloidogenic pattern. This fundamental research issue is evolving in parallel to the development of drugs and inhibitors able to modify protein self assembly towards amyloid fibrils. Small angle xray and neutron scattering experiments represent suitable methods to investigate protein amyloidogenesis and the possible effects of inhibitors: they are in-solution techniques, require low amount of sample and their time-resolution makes it possible to follow aggregation pattern. In this paper we review small angle x-ray and neutron scattering studies dedicated to investigate amyloid β peptide and α-synuclein, related to Alzheimer`s and Parkinson`s diseases, respectively, together with some other studies that introduced innovative models to describe with small angle scattering techniques amyloid fibrillation processes.

  7. 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

  8. Group sparsity based airborne wide angle SAR imaging

    Science.gov (United States)

    Wei, Zhonghao; Zhang, Bingchen; Bi, Hui; Lin, Yun; Wu, Yirong

    2016-10-01

    In this paper, we develop a group sparsity based wide angle synthetic aperture radar (WASAR) imaging model and propose a novel algorithm called backprojection based group complex approximate message passing (GCAMP-BP) to recover the anisotropic scene. Compare to conventional backprojection based complex approximate message passing (CAMP-BP) algorithm for the recovery of isotropic scene, the proposed method accommodates aspect dependent scattering behavior better and can produce better imagery. Simulated and experimental results are presented to demonstrate the validity of the proposed algorithm.

  9. 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.

  10. 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.

  11. Automatic Traffic Monitoring from an Airborne Wide Angle Camera System

    OpenAIRE

    Rosenbaum, Dominik; Charmette, Baptiste; Kurz, Franz; Suri, Sahil; Thomas, Ulrike; Reinartz, Peter

    2008-01-01

    We present an automatic traffic monitoring approach using data of an airborne wide angle camera system. This camera, namely the “3K-Camera”, was recently developed at the German Aerospace Center (DLR). It has a coverage of 8 km perpendicular to the flight direction at a flight height of 3000 m with a resolution of 45 cm and is capable to take images at a frame rate of up to 3 fps. Based on georeferenced images obtained from this camera system, a near real-time processing chain containing roa...

  12. Discrete angle biasing in Monte Carlo radiation transport

    Energy Technology Data Exchange (ETDEWEB)

    Cramer, S.N.

    1988-05-01

    An angular biasing procedure is presented for use in Monte Carlo radiation transport with discretized scattering angle data. As in more general studies, the method is shown to reduce statistical weight fluctuations when it is combined with the exponential transformation. This discrete data application has a simple analytic form which is problem independent. The results from a sample problem illustrate the variance reduction and efficiency characteristics of the combined biasing procedures, and a large neutron and gamma ray integral experiment is also calculated. A proposal is given for the possible code generation of the biasing parameter p and the preferential direction /ovr/Omega///sub 0/ used in the combined biasing schemes.

  13. Measurements related to CKM angle alpha in BABAR

    CERN Document Server

    Roos, L

    2004-01-01

    The BABAR collaboration measurements of the B -> pipi, B -> rhopi and B -> rhorho decays are presented. New results, from a 113 fb-1 data sample, on the time-dependent CP asymmetries of the longitudinally polarized component of the B0 -> rho+rho- channel are S_{rhorho,long}=-0.19 +/- 0.33 +/- 0.11 and C_{rhorho,long}=-0.23 +/- 0.24 +/- 0.14. Constraints on the Unitarity Triangle angle alpha from the pipi and the rhorho systems are derived.

  14. Surface nanobubbles: formation and universality of the contact angle

    CERN Document Server

    Weijs, J H; Lohse, D

    2011-01-01

    We study surface nanobubbles using molecular dynamics simulation of ternary (gas, liquid, solid) systems of Lennard-Jones fluids. They form for sufficiently low gas solubility in the liquid, i.e., for large relative gas concentration. For strong enough gas-solid attraction, the surface nanobubble is sitting on a gas layer, which forms in between the liquid and the solid. This gas layer is the reason for the universality of the contact angle, which we calculate from the microscopic parameters. Under the present equilibrium conditions the nanobubbles dissolve within less of a microsecond, consistent with the view that the experimentally found nanobubbles are stabilized by a nonequilibrium mechanism.

  15. Material loss angles from direct measurements of broadband thermal noise

    CERN Document Server

    Principe, Maria; Pierro, Vincenzo; DeSalvo, Riccardo; Taurasi, Ilaria; Villar, Akira E; Black, Eric D; Libbrecht, Kenneth G; Michel, Christophe; Morgado, Nazario; Pinard, Laurent

    2015-01-01

    We estimate the loss angles of the materials currently used in the highly reflective test-mass coatings of interferometric detectors of gravitational waves, namely Silica, Tantala, and Ti-dop ed Tantala, from direct measurement of coating thermal noise in an optical interferometer testbench, the Caltech TNI. We also present a simple predictive theory for the material properties of amorphous glassy oxide mixtures, which gives results in good agreement with our measurements on Ti-doped Tantala. Alternative measure ment methods and results are reviewed, and some critical issues are discussed.

  16. Aerial wetting contact angle measurement using confocal microscopy

    OpenAIRE

    Chesna, Jacob W.; Wiedmaier, Bob F.; Wang, Jinlin; Samara, Ayman; Leach, Richard K.; Her, Tsing-Hua; Smith, Stuart T.

    2016-01-01

    A method is presented in which the wetting contact angle of a sessile drop is acquired aerially using confocal techniques to measure the radius and the height of a droplet deposited on a planar surface. The repeatability of this method is typically less than 0.25°, and often less than 0.1°, for droplet diameters less than 1 mm. To evaluate accuracy of this method, an instrument uncertainty budget is developed, which predicts a combined uncertainty of 0.91° for a 1 mm diameter water droplet wi...

  17. Angle Resolved Performance Measurements on PV Glass and Modules

    DEFF Research Database (Denmark)

    Juutilainen, Line Tollund; Thorsteinsson, Sune; Poulsen, Peter Behrensdorff

    2016-01-01

    The angular response of PV-modules has significant impact on the energy production. This is especially pronounced in BIPV where installation angles often are far from optimal. Nevertheless, a gain in energy yield may be obtained by choosing a proper glass as superstrate. In this work we present...... the concept of PV balconies as cost efficient and easy way of integrating PV into buildings. The experimental work consists of the fabrication of single cell mini modules with different glass covering, and characterizing their angular response in a custom made setup, where only the direct sunlight is used...

  18. [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.

  19. Influence of visual angle on pattern reversal visual evoked potentials

    Directory of Open Access Journals (Sweden)

    Ruchi Kothari

    2014-01-01

    Full Text Available Purpose: The aim of this study was to find whether the visual evoked potential (VEP latencies and amplitude are altered with different visual angles in healthy adult volunteers or not and to determine the visual angle which is the optimum and most appropriate among a wide range of check sizes for the reliable interpretation of pattern reversal VEPs (PRVEPs. Materials and Methods: The present study was conducted on 40 healthy volunteers. The subjects were divided into two groups. One group consisted of 20 individuals (nine males and 11 females in the age range of 25-57 years and they were exposed to checks subtending a visual angle of 90, 120, and 180 minutes of arc. Another group comprised of 20 individuals (10 males and 10 females in the age range of 36-60 years and they were subjected to checks subtending a visual angle of 15, 30, and 120 minutes of arc. The stimulus configuration comprised of the transient pattern reversal method in which a black and white checker board is generated (full field on a VEP Monitor by an Evoked Potential Recorder (RMS EMG. EPMARK II. The statistical analysis was done by One Way Analysis of Variance (ANOVA using EPI INFO 6. Results: In Group I, the maximum (max. P100 latency of 98.8 ± 4.7 and the max. P100 amplitude of 10.05 ± 3.1 μV was obtained with checks of 90 minutes. In Group II, the max. P100 latency of 105.19 ± 4.75 msec as well as the max. P100 amplitude of 8.23 ± 3.30 μV was obtained with 15 minutes. The min. P100 latency in both the groups was obtained with checks of 120 minutes while the min. P100 amplitude was obtained with 180 minutes. A statistically significant difference was derived between means of P100 latency for 15 and 30 minutes with reference to its value for 120 minutes and between the mean value of P100 amplitude for 120 minutes and that of 90 and 180 minutes. Conclusion: Altering the size of stimulus (visual angle has an effect on the PRVEP parameters. Our study found that the 120

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

    OpenAIRE

    Mladen Brezović; Jaroslav Kljak; Stjepan Pervan; Alan Antonović

    2010-01-01

    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 o...

  1. Optimization of the space shuttle entry guidance lateral deadband, minimum bank angle logic

    Science.gov (United States)

    Bump, P. B.

    1977-01-01

    The lateral deadband and minimum bank angle schedule were studied. Results used by the analytic drag control entry guidance system are presented. Lateral deadband limits and configuration were investigated and possible changes in the minimum bank angle schedule to improve crossrange control and drag acceleration control for entry were examined. The study recommends a 12.5 deg lateral deadband to accommodate low dispersions of up to 23%.

  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. 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.

  4. Does the Panoramic Radiography Have the Power to Identify the Gonial Angle in Orthodontics?

    Science.gov (United States)

    Okşayan, Rıdvan; Aktan, Ali Murat; Sökücü, Oral; Haştar, Esin; Ciftci, Mehmet Ertuğrul

    2012-01-01

    Purpose. The objective of this study was to assess gonial angle under the angle classification by comparing panoramic radiograph and lateral cephalometric radiograph. Materials and Methods. 49 patients (25 males, 24 females) with an age range of 12–29 years participated in the present study. Subjects were retrospectively selected among those categorised as skeletal and dental Class I, II, and III malocclusion group. Using lateral cephalometric radiograph, mandibular and ramal planes were drawn and based on these planes. Gonial angle was determined from two tangents which were drawn from the inferior border of the mandible and posterior borders of the condyle and ramus of both sides in the panoramic radiographs. Multiple comparison tests (ANOVA) were used to determine differences between the three angle groups. Results. There were no significant differences between Class I, II, and III malocclusion group values of gonial angles determined by lateral cephalometric radiograph and panoramic radiographs (P > 0.05). Conclusion. Panoramic radiograph results were shown to be as reliable as lateral cephalometric radiograph in all angle classifications. Panoramic radiography can be used as an alternative radiographic technique to detect gonial angle in orthodontic patients. PMID:23365514

  5. 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.

  6. Precision determination of electron scattering angle by differential nuclear recoil energy method

    Energy Technology Data Exchange (ETDEWEB)

    Liyanage, N. [Physics Department, University of Virginia, Charlottesville, VA 22903 (United States); Saenboonruang, K., E-mail: fscikssa@ku.ac.th [Physics Department, University of Virginia, Charlottesville, VA 22903 (United States); Department of Applied Radiation and Isotopes, Faculty of Science, Kasetsart University, Chatuchak, Bangkok 10900 (Thailand)

    2015-12-01

    The accurate determination of the scattered electron angle is crucial to electron scattering experiments, both with open-geometry large-acceptance spectrometers and ones with dipole-type magnetic spectrometers for electron detection. In particular, for small central-angle experiments using dipole-type magnetic spectrometers, in which surveys are used to measure the spectrometer angle with respect to the primary electron beam, the importance of the scattering angle determination is emphasized. However, given the complexities of large experiments and spectrometers, the accuracy of such surveys is limited and insufficient to meet demands of some experiments. In this paper, we present a new technique for determination of the electron scattering angle based on an accurate measurement of the primary beam energy and the principle of differential nuclear recoil. This technique was used to determine the scattering angle for several experiments carried out at the Experimental Hall A, Jefferson Lab. Results have shown that the new technique greatly improved the accuracy of the angle determination compared to surveys.

  7. 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.

  8. 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.

  9. 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.

  10. A protocol for clinical evaluation of the carrying angle of the elbow by anatomic landmarks.

    Science.gov (United States)

    Zampagni, Maria Luisa; Casino, Daniela; Martelli, Sandra; Visani, Andrea; Marcacci, Maurilio

    2008-01-01

    The aim of this work was to present an in vivo protocol to estimate the carrying angle of the elbow in full extension. Forty-four arms were measured by using an electrogoniometer to acquire 3-dimensional coordinates of the landmarks. An algorithm based on the Cardan decomposition method was used to compute the carrying angle and the flexion and pronation angles of the elbow. The mean carrying angle was 12.42 degrees +/- 4.06 degrees , in agreement with the literature and with values obtained by a standard goniometer (r = 0.46; P = .000). Our protocol provided excellent repeatability (interclass correlation coefficient [ICC] = 0.85), greater than a goniometer (ICC = 0.76), and a standard error of measurement of only 1.62 degrees . Flexion was a significant factor (P = .01) in carrying angle estimation. This study suggests that the carrying angle cannot be estimated independently by the flexion angle, even when measured in apparently full extension, and it could be useful in elbow disorders, such as fractures or epicondylar disease management and evaluation of elbow reconstruction.

  11. Effect of anastomosis angle on hemodynamic of side-to-end radiocephalic arteriovenous fistula (RCAVF)

    Science.gov (United States)

    Hassan, Wan Anuar Wan; Osman, Kahar; Kadir, Mohammed Rafiq Abdul; Abdullah, Wan Ahmad Kamil Wan; Haron, Juhara; Ngali, Mohd Zamani

    2012-06-01

    Radiocephalic arteriovenous fistula (RCAVF) at wrist is the chosen access for hemodialysis. Most studies describe access complications without considering the effect of the anastomosis angle. In the present investigation, eighteen three-dimensional, simplified models of RCAVF were used to analyze the hemodynamic effect of anastomosis angle under fixed flow rate of 900 ml/min, corresponding to Reynolds number 950. EFD. Lab software was used in the flow simulation with steady flow conditions. The results show that high pressure drop was observed for RCAVF with smaller anastomosis angle. However, for cases with anastomosis angle larger than 45°, pressure drop became relatively constant. The results also show that large vortices appeared in cases with angle smaller than 30°. For cases with angle larger than 60°, low flow zone appeared at the inner wall that may lead to promotion of intimal thickening and formation of stenosis. Overall, for average flowrate, it is recommended that anastomosis angle should be maintained between 45° and 60° to minimize adverse effects.

  12. Proper Angle of Sono-guided Central Venous Line Insertion; a Brief Report

    Directory of Open Access Journals (Sweden)

    Hassan Barzegari

    2016-04-01

    Full Text Available Introduction: Determining the proper angle for inserting central venous catheter (CV line is of great importance for decreasing the complications and increasing success rate. The present study was designed to determine the proper angle of needle insertion for internal jugular vein catheterization. Methods: In the present case series study, candidate patients for catheterization of the right internal jugular vein under guidance of ultrasonography were studied. At the time of proper placing of the catheter, photograph was taken and Auto Cad 2014 software was used to measure the angles of the needle in the sagittal and axial planes, as well as patient’s head rotation. Result: 114 patients with the mean age of 56.96 ± 14.71 years were evaluated (68.4% male. The most common indications of catheterization were hemodialysis (55.3% and shock state (24.6%. The mean angles of needle insertion were 102.15 ± 6.80 for axial plane, 36.21 ± 3.12 for sagittal plane and the mean head rotation angle was 40.49 ± 5.09. Conclusion: Based on the results of the present study it seems that CV line insertion under the angles 102.15 ± 6.80 degrees in the axial plane, 36.21 ± 3.12 in the sagittal plane and 40.49 ± 5.09 head rotation yield satisfactory results. 

  13. 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.

  14. Low-angle X-ray scattering from spices

    Science.gov (United States)

    Desouky, Omar S.; 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°. This is equivalent to a value x=0.0565 Å -1, where x=sin( θ⧸2)⧸ λ. 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.

  15. 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…

  16. Develop your presentation skills

    CERN Document Server

    Theobald, Theo

    2016-01-01

    Going beyond handling nerves and presenting PowerPoint slides, the third edition of "Develop Your Presentation Skills "offers practical advice on developing a captivating presentation, constructing compelling content, and boosting self-confidence. The book includes three new chapters on delivering a "stripped down"presentation, using new media to engage with the audience, and handling being asked to present on short notice."

  17. 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.

  18. A simple method to obtain consistent and clinically meaningful pelvic angles from euler angles during gait analysis.

    Science.gov (United States)

    Wren, Tishya A L; Mitiguy, Paul C

    2007-08-01

    Clinical gait analysis usually describes joint kinematics using Euler angles, which depend on the sequence of rotation. Studies have shown that pelvic obliquity angles from the traditional tilt-obliquity-rotation (TOR) Euler angle sequence can deviate considerably from clinical expectations and have suggested that a rotation-obliquity-tilt (ROT) Euler angle sequence be used instead. We propose a simple alternate approach in which clinical joint angles are defined and exactly calculated in terms of Euler angles from any rotation sequence. Equations were derived to calculate clinical pelvic elevation, progression, and lean angles from TOR and ROT Euler angles. For the ROT Euler angles, obliquity was exactly the same as the clinical elevation angle, rotation was similar to the clinical progression angle, and tilt was similar to the clinical lean angle. Greater differences were observed for TOR. These results support previous findings that ROT is preferable to TOR for calculating pelvic Euler angles for clinical interpretation. However, we suggest that exact clinical angles can and should be obtained through a few extra calculations as demonstrated in this technical note.

  19. 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.

  20. Rapidly-Indexing Incremental-Angle Encoder

    Science.gov (United States)

    Christon, Philip R.; Meyer, Wallace W.

    1989-01-01

    Optoelectronic system measures relative angular position of shaft or other device to be turned, also measures absolute angular position after device turned through small angle. Relative angular position measured with fine resolution by optoelectronically counting finely- and uniformly-spaced light and dark areas on encoder disk as disk turns past position-sensing device. Also includes track containing coarsely- and nonuniformly-spaced light and dark areas, angular widths varying in proportion to absolute angular position. This second track provides gating and indexing signal.

  1. 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.

  2. Haptic discrimination of two-dimensional angles: influence of exploratory strategy.

    Science.gov (United States)

    Levy, Myriam; Bourgeon, Stéphanie; Chapman, C Elaine

    2007-04-01

    The aim of this study was to define the relative contribution of self-generated cutaneous and proprioceptive feedback to haptic shape discrimination by systematically constraining the exploratory strategy. Subjects (n = 23) explored pairs of two-dimensional (2-D) angles (standard angle, 90 degrees; comparison angles, 91 degrees -103 degrees) placed at arm's length from the subject, and identified the larger angle of each pair. The exploratory strategies included a reference condition, dynamic scan of the index finger over the entire object [combined cutaneous and proprioceptive (shoulder) feedback], and modified conditions, static touch of the intersection of the two bars that formed the angle using the index finger (cutaneous feedback) and dynamic scans of the object using a hand-held tool (proprioceptive feedback, shoulder). Discrimination thresholds (75% correct) were very similar for dynamic and static touch with the index finger. Thresholds varied as a function of the static contact duration (static touch likely reflects movement-related gating of self-generated tactile inputs. Together, the results suggested that cutaneous feedback alone may be sufficient to explain 2-D angle discrimination, because the added proprioceptive feedback did not improve performance. Also, threshold did not vary with the number of dynamic scans (one or two), suggesting that the critical information was gathered on the first pass over the angle. In contrast, when the angles were explored with the tool, the threshold increased relative to the corresponding reference condition from the same session (tool, 9.6 degrees +/- 0.9 degrees; dynamic scan with the finger, 6.2 degrees +/- 1.0 degrees). Thus, performance was poorer with proprioceptive feedback alone, suggesting that cutaneous feedback was relatively more important for 2-D haptic angle discrimination in the present experiment.

  3. Incidence angle modifiers. A general approach for energy calculations

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Maria Joao; Horta, Pedro; Mendes, Joao Farinha [INETI - Inst. Nacional de Engenharia Tecnologia, Inovacao, IP, Lisboa (Portugal); Collares Pereira, Manuel; Carbajal, Wildor Maldonado [AO SOL, Energias Renovaveis, S.A., Samora Correia (Portugal)

    2008-07-01

    The calculation of the energy (power) delivered by a given solar collector, requires special care in the consideration of the way it handles the incoming solar radiation. Some collectors, e.g. flat plate types, are easy to characterize from an optical point of view, given their rotational symmetry with respect to the incident angle on the entrance aperture. This in contrast with collectors possessing a 2D (or cylindrical) symmetry, such as collectors using evacuated tubes or CPC collectors, requiring the incident radiation to be decomposed and treated in two orthogonal planes. Analyses of incidence angle modifier (IAM) along these lines were done in the past for parabolic through, evacuated tube (ETC) or compound parabolic concentrator (CPC) collectors. The present paper addresses a general approach to IAM calculation, treating in a general, equivalent and systematic way all collector types. This approach will allow the proper handling of the solar radiation available to each collector type, subdivided in its different components, folding that with the optical effects present in the solar collector and enabling more accurate comparisons between different collector types, in terms of long term performance calculation. (orig.)

  4. A MODIFIED METHOD FOR IMAGE TRIANGULATION USING INCLINED ANGLES

    Directory of Open Access Journals (Sweden)

    B. Alsadik

    2016-06-01

    Full Text Available 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.

  5. 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/).

  6. 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.

  7. 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.

  8. 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...

  9. Active limited-angle tomographic phase microscope.

    Science.gov (United States)

    Kus, Arkadiusz; Krauze, Wojciech; Kujawinska, Malgorzata

    2015-01-01

    We demonstrate an active, holographic tomography system, working with limited angle of projections, realized by optical-only, diffraction-based beam steering. The system created for this purpose is a Mach–Zehnder interferometer modified to serve as a digital holographic microscope with a high numerical aperture illumination module and a spatial light modulator (SLM). Such a solution is fast and robust. Apart from providing an elegant solution to viewing angle shifting, it also adds new capabilities of the holographic microscope system. SLM, being an active optical element, allows wavefront correction in order to improve measurement accuracy. Integrated phase data captured with different illumination scenarios within a highly limited angular range are processed by a new tomographic reconstruction algorithm based on the compressed sensing technique: total variation minimization, which is applied here to reconstruct nonpiecewise constant samples. Finally, the accuracy of full measurement and the proposed processing path is tested for a calibrated three-dimensional micro-object as well as a biological object--C2C12 myoblast cell.

  10. Hidden topological angles and Lefschetz thimbles

    CERN Document Server

    Behtash, Alireza; Schaefer, Thomas; Unsal, Mithat

    2015-01-01

    We demonstrate the existence of hidden topological angles (HTAs) in a large class of quantum field theories and quantum mechanical systems. HTAs are distinct from theta-parameters in the lagrangian. They arise as invariant angle associated with saddle points of the complexified path integral and their descent manifolds (Lefschetz thimbles). Physical effects of HTAs become most transparent upon analytic continuation in $n_f$ to non-integer number of flavors, reducing in the integer $n_f$ limit to a $\\mathbb Z_2$ valued phase difference between dominant saddles. In ${\\cal N}=1$ super Yang-Mills theory we demonstrate the microscopic mechanism for the vanishing of the gluon condensate. The same effect leads to an anomalously small condensate in a QCD-like $SU(N)$ gauge theory with fermions in the two-index representation. The basic phenomenon is that, contrary to folklore, the gluon condensate can receive both positive and negative contributions in a semi-classical expansion. In quantum mechanics, a HTA leads to ...

  11. Trajectory shaping guidance law based on virtual angle with terminal constraints

    Institute of Scientific and Technical Information of China (English)

    Xijing Hu; Xuemei Huang

    2013-01-01

    A trajectory shaping guidance law based on virtual angle (TSGLBVA) is proposed for a re-entry vehicle with the con-straints of terminal impact angles and their time derivatives. In the view of differential properties of the maneuvering trajectory, a virtual angle and a virtual radius are defined. Also, the shaping trajectory of the vehicle is established by the polynomials of the virtual angle. Then, four optimized parameters are selected ac-cording to the theorem of parameters transformation presented in this paper. Final y, a convergent variant of the Nelder-Mead algo-rithm is adopted to obtain the reference trajectory, and a trajectory feedback tracking guidance law is designed. The simulation re-sults demonstrate that the TSGLBVA ensures the re-entry vehicle to impact a target precisely from a specified direction with smal terminal load factor command, as wel as to obtain a maximum or constrained terminal velocity according to various requirements.

  12. Small-angle X-ray scattering at the ESRF high-brillance beamline

    Energy Technology Data Exchange (ETDEWEB)

    Boesecke, P.; Diat, O. [European Synchrotron Radiation Facility (ESRF), 38 -Grenoble (France)

    1997-10-01

    The high-brilliance beamline (BL4/ID2) at the European synchrotron radiation facility (ESRF) in Grenoble has been constructed with the emphasis on time-resolved small-angle X-ray scattering and macromolecular crystallography. It has been open to users for two years. The beamline has opened up new areas in small-angle scattering research, facilitating (a) small-angle crystallography on structures with unit cells of several hundredths of nanometres, (b) overlap with the light scattering range for the study of optical systems, (c) high photon flux for time-resolved experiments and (d) a high spatial coherence allowing submicrometre imaging with X-rays. The set-up and the detector system of the small-angle scattering station are presented. A method for obtaining absolute scattering intensities is described. The parasitic background at the station is discussed in terms of absolute scattering intensities. (orig.). 22 refs.

  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. Estimation Normal Vector of Triangular Mesh Vertex by Angle and Centroid Weights and its Application

    Directory of Open Access Journals (Sweden)

    Yueping Chen

    2013-04-01

    Full Text Available To compute vertex normal of triangular meshes more accurately, this paper presents an improved algorithm based on angle and centroid weights. Firstly, four representational algorithms are analyzed by comparing their weighting characteristics such as angles, areas and centroids. The drawbacks of each algorithm are discussed. Following that, an improved algorithm is put forward based on angle and centroid weights. Finally, by taking the deviation angle between the nominal normal vector and the estimated one as the error evaluation standard factor, the triangular mesh models of spheres, ellipsoids, paraboloids and cylinders are used to analyze the performance of all these estimation algorithms. The machining and inspection operations of one mould part are conducted to verify the improved algorithm. Experimental results demonstrate that the algorithm is effective.

  15. 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.

  16. 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.

  17. The Interpretation of Dynamic Contact Angles Measured by the Wilhelmy Plate Method

    Science.gov (United States)

    Ramé

    1997-01-01

    We present an analysis for properly interpreting apparent dynamic contact angles measured using the Wilhelmy plate method at low capillary numbers, Ca. This analysis removes the ambiguity in current dynamic measurements which interpret data with the same formula as static measurements. We properly account for all forces, including viscous forces, acting on the plate as it moves into or out of a liquid bath. Our main result, valid at O(1) as Ca --> 0, relates the apparent dynamic contact angle to material-dependent, geometry-independent parameters necessary for describing dynamic wetting of a system. The special case of the apparent contact angle = pi/2 was solved to O(Ca). This O(Ca) solution can guide numerical work necessary for higher Ca's and arbitrary values of the apparent contact angle. These results make the Wilhelmy plate a viable method for determining material parameters for dynamic spreading.

  18. A Hydrodynamic Model of Dynamic Contact Angle Hysteresis.

    Science.gov (United States)

    contact angle hysteresis is developed in terms of the interaction of capillary, viscous, and...used to obtain the equations which describe the contact angle region and thereby to define the dynamic contact angle . The analysis is limited to...velocity dependence of the receding contact angle and of the thickness of the deposited film of the receding interface of a wetting liquid are determined as functions of the capillary, viscous, and disjoining forces.

  19. Studying of the Contact Angle Hysteresis on Various Surfaces

    OpenAIRE

    Kirichenko E. O.; Gatapova E. Ya.

    2016-01-01

    This paper is devoted to investigation of the contact angle hysteresis on various surfaces. It was carried out by two different methods: measuring the advancing and the receding contact angles and measuring the contact angles at water droplet evaporation under isothermal conditions. Data obtained using two methods have been compared. The influence of the contact angle hysteresis on the mode of the drop evaporation has been shown.

  20. Studying of the Contact Angle Hysteresis on Various Surfaces

    Directory of Open Access Journals (Sweden)

    Kirichenko E. O.

    2016-01-01

    Full Text Available This paper is devoted to investigation of the contact angle hysteresis on various surfaces. It was carried out by two different methods: measuring the advancing and the receding contact angles and measuring the contact angles at water droplet evaporation under isothermal conditions. Data obtained using two methods have been compared. The influence of the contact angle hysteresis on the mode of the drop evaporation has been shown.

  1. 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

  2. Modeling granular material flows: The angle of repose, fluidization and the cliff collapse problem

    Science.gov (United States)

    Holsapple, Keith A.

    2013-07-01

    I discuss theories of granular material flows, with application to granular flows on the earth and planets. There are two goals. First, there is a lingering belief of some that the standard continuum plasticity Mohr-Coulomb and/or Drucker-Prager models are not adequate for many large-scale granular flow problems. The stated reason for those beliefs is the fact that the final slopes of the run-outs in collapse, landslide problems, and large-scale cratering are well below the angle of repose of the material. That observation, combined with the supposition that in those models flow cannot occur with slopes less than the angle of repose, has led to a number of researchers suggesting a need for lubrication or fluidization mechanisms and modeling. That issue is investigated in detail and shown to be false. A complete analysis of slope failures according to the Mohr-Coulomb model is presented, with special attention to the relations between the angle of repose and slope failures. It is shown that slope failure can occur for slope angles both larger than and smaller than the angle of repose. Second, to study the details of landslide run-outs, finite-difference continuum code simulations of the prototypical cliff collapse problem, using the classical plasticity models, are presented, analyzed and compared to experiments. Although devoid of any additional fluidization models, those simulations match experiments in the literature extremely well. The dynamics of this problem introduces additional important features relating to the run-out and final slope angles. The vertical free surface begins to fall at the initial 90° and flow continues to a final slope less than 10°. The detail in the calculation is examined to show why flow persists at slope angles that appear to be less than the angle of repose. The motions include regions of solid-like, fluid-like, and gas-like flows without invoking any additional models.

  3. Maximum Atmospheric Entry Angle for Specified Retrofire Impulse

    Directory of Open Access Journals (Sweden)

    T. N. Srivastava

    1969-07-01

    Full Text Available Maximum atmospheric entry angles for vehicles initially moving in elliptic orbits are investigated and it is shown that tangential retrofire impulse at the apogee results in the maximum entry angle. Equivalence of maximizing the entry angle and minimizing the retrofire impulse is also established.

  4. INFLUENCE OF SURFACE-ROUGHNESS ON THE WETTING ANGLE

    NARCIS (Netherlands)

    Zhou, X.B; de Hosson, J.T.M.

    1995-01-01

    In this paper the influence of surface roughness on contact angles in the system of liquid Al wetting solid surfaces of Al2O3 has been studied. It was observed that contact angles of liquid Al vary significantly on different rough surfaces of Al2O3 A model is proposed to correlate contact angles wit

  5. Influence of higher order modes on angled-facet amplifiers

    DEFF Research Database (Denmark)

    Wang, Z.; Mikkelsen, B.; Stubkjær, Kristian

    1991-01-01

    The influence of the first-order mode on the residual reflectivity of angled-facet amplifiers is analyzed. For a 7 degrees angled-facet ridge waveguide amplifier with a single-layer antireflective (AR) coating, a gain ripple lower than 1-dB at 25-dB gain can be obtained independent...... by increasing the facet angles to 10 degrees...

  6. 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

  7. Optimal angle reduction - a behavioral approach to linear system approximation

    NARCIS (Netherlands)

    Roorda, Berend; Fuhrmann, P.A.

    2001-01-01

    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 analyz

  8. 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.

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

    Science.gov (United States)

    Barreto, Gustavo Mattos

    2013-01-01

    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.

  10. 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.

  11. Filtering chromatic aberration for wide acceptance angle electrostatic lenses.

    Science.gov (United States)

    Fazekas, Ádám; Tóth, László

    2014-07-01

    Chromatic aberration is a major issue for imaging mainly with large acceptance angle electrostatic lenses. Its correction is necessary to take advantage of the outstanding spatial and angular resolution that these lenses provide. We propose a method to eliminate the effect of chromatic aberration on the measured images by determining the impact resulting from higher and lower kinetic energies. Based on a spectral image sequence and a matrix, which describes the transmission function of the lens, a system of linear equations is solved to approximate the 2D spectral intensity distribution of the sample surface. We present the description of our method and preliminary test results, which show significant contrast and image quality improvement. The presented algorithm can also be applied as a software-based energy analyzer.

  12. 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.

  13. 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 contain...

  14. Marketing through Video Presentations.

    Science.gov (United States)

    Newhart, Donna

    1989-01-01

    Discusses the advantages of using video presentations as marketing tools. Includes information about video news releases, public service announcements, and sales/marketing presentations. Describes the three stages in creating a marketing video: preproduction planning; production; and postproduction. (JOW)

  15. 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.

  16. 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.)

  17. The effect of shoreline recreational angling activities on aquatic and riparian habitat within an urban environment: implications for conservation and management.

    Science.gov (United States)

    O'Toole, Amanda C; Hanson, Kyle C; Cooke, Steven J

    2009-08-01

    There is growing concern that recreational shoreline angling activity may negatively impact littoral and riparian habitats independent of any direct or indirect influences of fish harvest or fishing mortality through mechanisms such as disturbance (e.g., trampling, erosion) and pollution (e.g., littering). We sampled a suite of aquatic and terrestrial variables (i.e., water quality, aquatic and terrestrial macrophytes, soil compaction, anthropogenic refuse) at 14 high shoreline angling-activity sites (identified by way of interviews with conservation officers and angling clubs) within an urban area (Ottawa, Canada). For each high angling-activity site, a nearby corresponding low angling-activity site was sampled for comparison. We found that the percentage of barren area and soil compaction were greater in areas of high angling activity compared with areas that experienced relatively low angling activity. In addition, terrestrial and aquatic macrophyte density, height, and diversity were lower at high angling-activity sites. Angling- and non-angling-related litter was present in large quantities at each of the high angling-activity sites, and comparatively little litter was found at low angling-activity sites. Collectively, these findings indicate that shoreline angling does alter the riparian environment, contributing to pollution and environmental degradation in areas of high angling intensity. With growing interest in providing urban angling opportunities and in response to increasing interest in developing protected areas and parks, a better understanding of the ecologic impacts of shoreline angling is necessary to address multiuser conflicts, to develop angler outreach and educational materials, and to optimize management of angling effort to maintain ecologic integrity of riparian and aquatic ecosystems.

  18. Make Your Presentation Powerful

    Science.gov (United States)

    Palmer, Erik

    2015-01-01

    "I was planning on doing a lot of work today during your presentation, but I couldn't get anything done. I just had to pay attention!" The author received this unexpected feedback from a teacher at the end of a presentation he gave, and although he considered it a compliment, it made him reflect on the dire state of presentations in…

  19. 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…

  20. 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

  1. 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

  2. Characterisation of High Grazing Angle X-band Sea-clutter Doppler Spectra

    Science.gov (United States)

    2013-08-01

    Pustovoytenko 1976, Lewis & Olin 1980] propose that ‘wedge scattering’ is present at low grazing angles where surface elements are present with a small...1998) Lineshape analysis of breaking- wave doppler spectra, IEE Proceedings of Radar, Sonar and Navigation 145(2), 135–139. Lewis, R. L. & Olin , I. D

  3. Mesoscopic modeling of a two-phase flow in the presence of boundaries: The contact angle

    NARCIS (Netherlands)

    Benzi, R.; Biferale, L.; Sbragaglia, M.; Succi, S.; Toschi, F.

    2006-01-01

    We present a mesoscopic model, based on the Boltzmann equation, for the interaction between a solid wall and a nonideal fluid. We present an analytic derivation of the contact angle in terms of the surface tension between the liquid-gas, the liquid-solid, and the gas-solid phases. We study the depen

  4. Wide Angle Michelson Doppler Imaging Interferometer (WAMDII)

    Science.gov (United States)

    Roberts, B.

    1986-01-01

    The wide angle Michelson Doppler imaging interferometer (WAMDII) is a specialized type of optical Michelson interferometer working at sufficiently long path difference to measure Doppler shifts and to infer Doppler line widths of naturally occurring upper atmospheric Gaussian line emissions. The instrument is intended to measure vertical profiles of atmospheric winds and temperatures within the altitude range of 85 km to 300 km. The WAMDII consists of a Michelson interferometer followed by a camera lens and an 85 x 106 charge coupled device photodiode array. Narrow band filters in a filter wheel are used to isolate individual line emissions and the lens forms an image of the emitting region on the charge coupled device array.

  5. Wide-angle energy-momentum spectroscopy

    CERN Document Server

    Dodson, Christopher M; Li, Dongfang; Zia, Rashid

    2014-01-01

    Light emission is defined by its distribution in energy, momentum, and polarization. Here, we demonstrate a method that resolves these distributions by means of wide-angle energy-momentum spectroscopy. Specifically, we image the back focal plane of a microscope objective through a Wollaston prism to obtain polarized Fourier-space momentum distributions, and disperse these two-dimensional radiation patterns through an imaging spectrograph without an entrance slit. The resulting measurements represent a convolution of individual radiation patterns at adjacent wavelengths, which can be readily deconvolved using any well-defined basis for light emission. As an illustrative example, we use this technique with the multipole basis to quantify the intrinsic emission rates for electric and magnetic dipole transitions in europium-doped yttrium oxide (Eu$^{3+}$:Y$_{2}$O$_{3}$) and chromium-doped magnesium oxide (Cr$^{3+}$:MgO). Once extracted, these rates allow us to reconstruct the full, polarized, two-dimensional radi...

  6. Intrinsic polarization angle ambiguity in Faraday tomography

    CERN Document Server

    Kumazaki, Kohei; Ideguchi, Shinsuke; Kurayama, Tomoharu; Takahashi, Keitaro

    2014-01-01

    Faraday tomography is a powerful method to diagnose polarizations and Faraday rotations along the line of sight. Quality of Faraday tomography is, however, limited by several conditions. Recently, it is reported that Faraday tomography indicates false signals in some specific situations. In this paper, we systematically investigate the condition of the appearance of false signals in Faraday tomography. We study the situations that we observe two sources within a beam, and change the intrinsic polarization angles, rotation measures, intensities, and frequency coverage. We find that false signals arise when rotation measure between the sources is less than 1.5 times the full width at half maximum of the rotation measure spread function. False signals also depend on the intensity ratio between the sources and are reduced for large ratio. On the other hand, the appearance of false signals does not depend on frequency coverage, meaning that the uncertainty should be correctly understood and taken into consideratio...

  7. Sinusoidal Order Estimation Using Angles between Subspaces

    Directory of Open Access Journals (Sweden)

    Søren Holdt Jensen

    2009-01-01

    Full Text Available We consider the problem of determining the order of a parametric model from a noisy signal based on the geometry of the space. More specifically, we do this using the nontrivial angles between the candidate signal subspace model and the noise subspace. The proposed principle is closely related to the subspace orthogonality property known from the MUSIC algorithm, and we study its properties and compare it to other related measures. For the problem of estimating the number of complex sinusoids in white noise, a computationally efficient implementation exists, and this problem is therefore considered in detail. In computer simulations, we compare the proposed method to various well-known methods for order estimation. These show that the proposed method outperforms the other previously published subspace methods and that it is more robust to the noise being colored than the previously published methods.

  8. 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.

  9. 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...

  10. 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.

  11. Pneumatic Rotary Actuator Angle Control System

    Institute of Scientific and Technical Information of China (English)

    王鹏; 彭光正; 伍清河

    2003-01-01

    Based on the adaptive control method, a kind of parameter adjustor was used to control pneumatic rotary actuator to track the expected output. The system uses electropneumatic proportional valve as control device, which adjusts the gas flow of actuator 's two cavities, then changes the pressure of cavity and pushes the piston of actuator to move, so the rotary actuator 's axis can be made to revolve to the required angle at last. According to the characteristic of pneumatic system, the control system was described with a fourth-order mathematic model. The control rule is deduced by model reference adaptive control method. By the result of experiment, it was proved that by using the adaptive control method, the output of rotary actuator could track the expected value timely and accurately.

  12. A superconducting large-angle magnetic suspension

    Science.gov (United States)

    Downer, James R.; Anastas, George V., Jr.; Bushko, Dariusz A.; Flynn, Frederick J.; Goldie, James H.; Gondhalekar, Vijay; Hawkey, Timothy J.; Hockney, Richard L.; Torti, Richard P.

    1992-01-01

    SatCon Technology Corporation has completed a Small Business Innovation Research (SBIR) Phase 2 program to develop a Superconducting Large-Angle Magnetic Suspension (LAMS) for the NASA Langley Research Center. The Superconducting LAMS was a hardware demonstration of the control technology required to develop an advanced momentum exchange effector. The Phase 2 research was directed toward the demonstration for the key technology required for the advanced concept CMG, the controller. The Phase 2 hardware consists of a superconducting solenoid ('source coils') suspended within an array of nonsuperconducting coils ('control coils'), a five-degree-of-freedom positioning sensing system, switching power amplifiers, and a digital control system. The results demonstrated the feasibility of suspending the source coil. Gimballing (pointing the axis of the source coil) was demonstrated over a limited range. With further development of the rotation sensing system, enhanced angular freedom should be possible.

  13. Disequilibrium dihedral angles in dolerite sills

    Science.gov (United States)

    Holness, Marian B.; Richardson, Chris; Helz, Rosalind T.

    2012-01-01

    The geometry of clinopyroxene-plagioclase-plagioclase junctions in mafic rocks, measured by the median dihedral angle Θcpp, is created during solidification. In the solidifying Kilauea Iki (Hawaii) lava lake, the wider junctions between plagioclase grains are the first to be filled by pyroxene, followed by the narrower junctions. The final Θcpp, attained when all clinopyroxene-plagioclase-plagioclase junctions are formed, is 78° in the upper crust of the lake, and 85° in the lower solidification front. Θcpp in the 3.5-m-thick Traigh Bhàn na Sgùrra sill (Inner Hebrides) is everywhere 78°. In the Whin Sill (northern England, 38 m thick) and the Portal Peak sill (Antarctica, 129 m thick), Θcpp varies symmetrically, with the lowest values at the margins. The 266-m-thick Basement Sill (Antarctica) has asymmetric variation of Θcpp, attributed to a complex filling history. The chilled margins of the Basement Sill are partially texturally equilibrated, with high Θcpp. The plagioclase grain size in the two widest sills varies asymmetrically, with the coarsest rocks found in the upper third. Both Θcpp and average grain size are functions of model crystallization times. Θcpp increases from 78° to a maximum of ∼100° as the crystallization time increases from 1 to 500 yr. Because the use of grain size as a measure of crystallization time is dependent on an estimate of crystal growth rates, dihedral angles provide a more direct proxy for cooling rates in dolerites.

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

    Science.gov (United States)

    Senthilkumaran, S; Balamurgan, N; Arthanari, K; Thirumalaikolundusubramanian, P

    2010-01-01

    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.

  17. Mandibular advancement surgery in high-angle and low-angle class II patients: different long-term skeletal responses.

    Science.gov (United States)

    Mobarak, K A; Espeland, L; Krogstad, O; Lyberg, T

    2001-04-01

    The objective of this cephalometric study was to compare skeletal stability and the time course of postoperative changes in high-angle and low-angle Class II patients after mandibular advancement surgery. The subjects were 61 consecutive mandibular retrognathism patients whose treatment included bilateral sagittal split osteotomy and rigid fixation. The patients were divided according to the preoperative mandibular plane angle; the 20 patients with the lowest mandibular plane angle (20.8 degrees +/- 4.9 degrees ) constituted the low-angle group, while the 20 cases with the highest mandibular plane angle (43.0 degrees +/- 4.0 degrees ) represented the high-angle group. Lateral cephalograms were taken on 6 occasions: immediately before surgery, immediately after surgery, 2 and 6 months after surgery, and 1 and 3 years after surgery. Results demonstrated that the high-angle and low-angle groups had different patterns of surgical and postoperative changes. High-angle patients were associated with both a higher frequency and a greater magnitude of horizontal relapse. While 95% of the total relapse took place during the first 2 months after surgery in the low-angle group, high-angle patients demonstrated a more continuous relapse pattern, with a significant proportion (38%) occurring late in the follow-up period. Possible reasons for the different postsurgical response are discussed.

  18. Optimal relative view angles for an object viewed multiple times

    Science.gov (United States)

    Gilani, Syed U.; Shende, Apoorva; Nguyen, Bao; Stilwell, Daniel J.

    2015-05-01

    Typically, the detection of an object of interest improves as we view the object from multiple angles. For cases where viewing angle matters, object detection can be improved further by optimally selecting the relative angles of multiple views. This motivates the search for viewing angles that maximize the expected probability of detection. Although our work is motivated by applications in subsea sensing, our fundamental analysis is easily adapted for other classes of applications. The specific challenge that motivates our work is the selection of optimal viewing angles for subsea sensing in which sonar is used for bathymetric imaging.

  19. Measurement of dihedral angles by scanning electron microscopy.

    Science.gov (United States)

    Achutaramayya, G.; Scott, W. D.

    1973-01-01

    The extension of Hoover's (1971) technique to the case of dihedral-angle measurement is described. Dihedral angles are often determined by interferometry on thermally grooved grain boundaries to obtain information on relative interfacial energies. In the technique considered the measured angles approach the true angles as the tilt angle approaches 90 deg. It is pointed out that the scanning electron microscopy method provides a means of seeing the real root of a groove at a lateral magnification which is higher than that obtainable with interferometry.

  20. Development of a Contact Angle Measurement Method Based Upon Geometry

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Su; Pyo, Na Young; Seo, Seung Hee [Ewha Womans University, Seoul (Korea); Choi, Woo Jin [Suwon University, Suwon (Korea); Kwon, Young Shik [Suwon Science College, Suwon (Korea)

    1998-12-31

    A new way of contact angle measurement is derived based on simple geometrical calculation. Without using complicated contact angle measurement instrument, just measuring the diameter and height of liquid lens made it possible to calculate the contact angle value with a reasonable reliability. To validate the contact angle value obtained by this method, contact angle of the same liquid lens is measured using conventional goniometer and it is verified that two values are nearly same within the limit of observational error. (author). 6 refs., 2 tabs., 3 figs.

  1. 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.

  2. A robust polynomial fitting approach for contact angle measurements.

    Science.gov (United States)

    Atefi, Ehsan; Mann, J Adin; Tavana, Hossein

    2013-05-14

    Polynomial fitting to drop profile offers an alternative to well-established drop shape techniques for contact angle measurements from sessile drops without a need for liquid physical properties. Here, we evaluate the accuracy of contact angles resulting from fitting polynomials of various orders to drop profiles in a Cartesian coordinate system, over a wide range of contact angles. We develop a differentiator mask to automatically find a range of required number of pixels from a drop profile over which a stable contact angle is obtained. The polynomial order that results in the longest stable regime and returns the lowest standard error and the highest correlation coefficient is selected to determine drop contact angles. We find that, unlike previous reports, a single polynomial order cannot be used to accurately estimate a wide range of contact angles and that a larger order polynomial is needed for drops with larger contact angles. Our method returns contact angles with an accuracy of contact angles in a wide range with a fourth-order polynomial. We show that this approach returns dynamic contact angles with less than 0.7° error as compared to ADSA-P, for the solid-liquid systems tested. This new approach is a powerful alternative to drop shape techniques for estimating contact angles of drops regardless of drop symmetry and without a need for liquid properties.

  3. Profile of angle closure in a tertiary care center in north India

    Directory of Open Access Journals (Sweden)

    Ichhpujani Parul

    2010-01-01

    Full Text Available Purpose: To study the demographic and clinical profile of the types of primary angle closure patients presenting at a tertiary care center in North India. Materials and Methods: Clinic records of patients diagnosed as primary angle closure were reviewed. International Society of Geographical and Epidemiological Ophthalmology (ISGEO classification scheme was used to categorize patients. Demographic and clinical data including prior management was collected and analyzed. Main Outcome measures were age, sex, symptomatology, best corrected visual acuity (BCVA, intraocular pressure (IOP, gonioscopy, optic disc assessment and visual field defects. Logistic regression model and receiver operating curve (ROC were calculated for predictors of type of glaucoma. Results: Eight hundred and fourteen patients (1603 eyes; males: 380, females: 434 were diagnosed to have various subtypes of angle closure. Mean (±SD age at presentation was significantly higher for males (57.57 ± 11.62 years as compared to females (53.64 ± 10.67 years ( P < 0001. Primary angle closure glaucoma (PACG was most frequently diagnosed subtype (49.38% followed by Primary angle closure (PAC (39.68% and Primary angle closure suspect (PACS (10.93% respectively. The three subtypes differed significantly among their mean IOP (on ANOVA, F = 14.04; P < 0001 using Greenhouse-Geisser correction. Univariate analysis was done to find significant predictors for the outcome of PACG. Logistic regression model and ROC containing the significant predictors yielded a very high AUC of 0.93 with strong discriminatory ability for PACG. Conclusion: In our hospital-based study, the significant predictors for the outcome of PACG included male gender, diminution of vision, the presence of pain and worsening grades of BCVA. Nearly half of PACG presented with advanced disease. In spite of one-third of the patients being diagnosed as angle closure prior to referral, only 8.34% had iridotomy (laser or surgical

  4. 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.

  5. The effect of insertion angle on orthodontic mini-screw torque

    Directory of Open Access Journals (Sweden)

    Seyed Hamid Raji

    2014-01-01

    Full Text Available Background: Primary stability is an important factor for the clinical success of orthodontic mini-screws. The present study made an attempt to evaluate the effect of insertion angle changes on the maximum insertion and removal torque of orthodontic mini-screws. Materials and Methods: In this experimental study, 72 mini-screws (Dual Top Anchor System, Jeil, 1.6 mm diameter, 8 mm length were used. They were randomly divided into four equal groups and inserted in poly-carbonate plates with 3 mm thickness. Then, their maximum insertion torque (MIT and maximum removal torque (MRT were recorded using a digital torque tester/screwdriver. Each group had a different insertion angle (90°, 75°, 60° and 45°. The data were analyzed by SPSS software (version 18 using one-way ANOVA and post-hoc Tukey′s tests. The level of significance was set at 0.05. Results: The maximum MIT was observed in 45° insertion angle (14.84 Ncm and the minimum MIT was reported in 75° insertion angle (12.66 Ncm. The maximum MRT was observed in 45° insertion angle (23.21 Ncm and the minimum MRT was reported in the 90° insertion angle (17.43 Ncm. Conclusion: Oblique insertion of the mini-screws results in higher insertion and removal torques and probably more primary stability compared to the vertical insertion.

  6. Multilevel Models for the Analysis of Angle-Specific Torque Curves with Application to Master Athletes.

    Science.gov (United States)

    Carvalho, Humberto M

    2015-12-22

    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 60º·s(-1) were considered within a range of motion between 5º and 85º (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 angle-specific 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.

  7. UV-Vis reflection spectroscopy under variable angle incidence at the air-liquid interface.

    Science.gov (United States)

    Roldán-Carmona, Cristina; Rubia-Payá, Carlos; Pérez-Morales, Marta; Martín-Romero, María T; Giner-Casares, Juan J; Camacho, Luis

    2014-03-07

    The UV-Vis reflection spectroscopy (UV-Vis-RS) in situ at the air-liquid interface provides information about tilt and aggregation of chromophores in Langmuir monolayers. This information is particularly important given in most cases the chromophore is located at the polar region of the Langmuir monolayer. This region of the Langmuir monolayers has been hardly accessible by other experimental techniques. In spite of its enormous potential, the application of UV-Vis-RS has been limited mainly to reflection measurements under light normal incidence or at lower incidence angles than the Brewster angle. Remarkably, this technique is quite sensitive to the tilt of the chromophores at values of incidence angles close to or larger than the Brewster angle. Therefore, a novel method to obtain the order parameter of the chromophores at the air-liquid interface by using s- and p-polarized radiation at different incidence angles is proposed. This method allowed for the first time the experimental observation of the two components with different polarization properties of a single UV-Vis band at the air-liquid interface. The method of UV-Vis spectroscopy under variable angle incidence is presented as a new tool for obtaining rich detailed information on Langmuir monolayers.

  8. Development of empirical correlation of peak friction angle with surface roughness of discontinuities using tilt test

    Science.gov (United States)

    Serasa, Ailie Sofyiana; Lai, Goh Thian; Rafek, Abdul Ghani; Simon, Norbert; Hussein, Azimah; Ern, Lee Khai; Surip, Noraini; Mohamed, Tuan Rusli

    2016-11-01

    The significant influence of surface roughness of discontinuity surfaces is a quantity that is fundamental to the understanding of shear strength of geological discontinuities. This is due to reason that the shear strength of geological discontinuities greatly influenced the mechanical behavior of a rock mass especially in stability evaluation of tunnel, foundation, and natural slopes. In evaluating the stability of these structures, the study of peak friction angle (Φpeak) of rough discontinuity surfaces has become more prominent seeing that the shear strength is a pivotal factor causing failures. The measurement of peak friction angle however, requires an extensive series of laboratory tests which are both time and cost demanding. With that in mind, this publication presents an approach in the form of an experimentally determined polynomial equation to estimate peak friction angle of limestone discontinuity surfaces by measuring the Joint Roughness Coefficient (JRC) values from tilt tests, and applying the fore mentioned empirical correlation. A total of 1967 tilt tests and JRC measurements were conducted in the laboratory to determine the peak friction angles of rough limestone discontinuity surfaces. A polynomial equation of ɸpeak = -0.0635JRC2 + 3.95JRC + 25.2 that exhibited 0.99 coefficient of determination (R2) were obtained from the correlation of JRC and peak friction angles. The proposed correlation offers a practical method for estimation of peak friction angles of rough discontinuity surfaces of limestone from measurement of JRC in the field.

  9. 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.

  10. Behavioural present value

    OpenAIRE

    Krzysztof Piasecki

    2013-01-01

    Impact of chosen behavioural factors on imprecision of present value is discussed here. The formal model of behavioural present value is offered as a result of this discussion. Behavioural present value is described here by fuzzy set. These considerations were illustrated by means of extensive numerical case study. Finally there are shown that in proposed model the return rate is given, as a fuzzy probabilistic set.

  11. 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.

  12. Modeling Vehicle Collision Angle in Traffic Crashes Based on Three-Dimensional Laser Scanning Data

    Directory of Open Access Journals (Sweden)

    Nengchao Lyu

    2017-02-01

    Full Text Available In road traffic accidents, the analysis of a vehicle’s collision angle plays a key role in identifying a traffic accident’s form and cause. However, because accurate estimation of vehicle collision angle involves many factors, it is difficult to accurately determine it in cases in which less physical evidence is available and there is a lack of monitoring. This paper establishes the mathematical relation model between collision angle, deformation, and normal vector in the collision region according to the equations of particle deformation and force in Hooke’s law of classical mechanics. At the same time, the surface reconstruction method suitable for a normal vector solution is studied. Finally, the estimation model of vehicle collision angle is presented. In order to verify the correctness of the model, verification of multi-angle collision experiments and sensitivity analysis of laser scanning precision for the angle have been carried out using three-dimensional (3D data obtained by a 3D laser scanner in the collision deformation zone. Under the conditions with which the model has been defined, validation results show that the collision angle is a result of the weighted synthesis of the normal vector of the collision point and the weight value is the deformation of the collision point corresponding to normal vectors. These conclusions prove the applicability of the model. The collision angle model proposed in this paper can be used as the theoretical basis for traffic accident identification and cause analysis. It can also be used as a theoretical reference for the study of the impact deformation of elastic materials.

  13. 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.

  14. Statistical contact angle analyses; "slow moving" drops on a horizontal silicon-oxide surface.

    Science.gov (United States)

    Schmitt, M; Grub, J; Heib, F

    2015-06-01

    Sessile drop experiments on horizontal surfaces are commonly used to characterise surface properties in science and in industry. The advancing angle and the receding angle are measurable on every solid. Specially on horizontal surfaces even the notions themselves are critically questioned by some authors. Building a standard, reproducible and valid method of measuring and defining specific (advancing/receding) contact angles is an important challenge of surface science. Recently we have developed two/three approaches, by sigmoid fitting, by independent and by dependent statistical analyses, which are practicable for the determination of specific angles/slopes if inclining the sample surface. These approaches lead to contact angle data which are independent on "user-skills" and subjectivity of the operator which is also of urgent need to evaluate dynamic measurements of contact angles. We will show in this contribution that the slightly modified procedures are also applicable to find specific angles for experiments on horizontal surfaces. As an example droplets on a flat freshly cleaned silicon-oxide surface (wafer) are dynamically measured by sessile drop technique while the volume of the liquid is increased/decreased. The triple points, the time, the contact angles during the advancing and the receding of the drop obtained by high-precision drop shape analysis are statistically analysed. As stated in the previous contribution the procedure is called "slow movement" analysis due to the small covered distance and the dominance of data points with low velocity. Even smallest variations in velocity such as the minimal advancing motion during the withdrawing of the liquid are identifiable which confirms the flatness and the chemical homogeneity of the sample surface and the high sensitivity of the presented approaches.

  15. VizieR Online Data Catalog: Jet angles and gamma-ray energetics estimations (Goldstein+, 2016)

    Science.gov (United States)

    Goldstein, A.; Connaughton, V.; Briggs, M. S.; Burns, E.

    2016-04-01

    We present a method to estimate the jet opening angles of long duration gamma-ray bursts (GRBs) using the prompt gamma-ray energetics and an inversion of the Ghirlanda relation, which is a correlation between the time-integrated peak energy of the GRB prompt spectrum and the collimation-corrected energy in gamma-rays. The derived jet opening angles using this method and detailed assumptions match well with the corresponding inferred jet opening angles obtained when a break in the afterglow is observed. Furthermore, using a model of the predicted long GRB redshift probability distribution observable by the Fermi Gamma-ray Burst Monitor (GBM), we estimate the probability distributions for the jet opening angle and rest-frame energetics for a large sample of GBM GRBs for which the redshifts have not been observed. Previous studies have only used a handful of GRBs to estimate these properties due to the paucity of observed afterglow jet breaks, spectroscopic redshifts, and comprehensive prompt gamma-ray observations, and we potentially expand the number of GRBs that can be used in this analysis by more than an order of magnitude. In this analysis, we also present an inferred distribution of jet breaks which indicates that a large fraction of jet breaks are not observable with current instrumentation and observing strategies. We present simple parameterizations for the jet angle, energetics, and jet break distributions so that they may be used in future studies. (1 data file).

  16. Investigation of surface porosity measurements and compaction pressure as means to ensure consistent contact angle determinations.

    Science.gov (United States)

    Holm, René; Borkenfelt, Simon; Allesø, Morten; Andersen, Jens Enevold Thaulov; Beato, Stefania; Holm, Per

    2016-02-10

    Compounds wettability is critical for a number of central processes including disintegration, dispersion, solubilisation and dissolution. It is therefore an important optimisation parameter both in drug discovery but also as guidance for formulation selection and optimisation. Wettability for a compound is determined by its contact angle to a liquid, which in the present study was measured using the sessile drop method applied to a disc compact of the compound. Precise determination of the contact angle is important should it be used to either rank compounds or selected excipients to e.g. increase the wetting from a solid dosage form. Since surface roughness of the compact has been suggested to influence the measurement this study investigated if the surface quality, in terms of surface porosity, had an influence on the measured contact angle. A correlation to surface porosity was observed, however for six out of seven compounds similar results were obtained by applying a standard pressure (866 MPa) to the discs in their preparation. The data presented in the present work therefore suggest that a constant high pressure should be sufficient for most compounds when determining the contact angle. Only for special cases where compounds have poor compressibility would there be a need for a surface-quality-control step before the contact angle determination.

  17. ESTIMATING LONG GRB JET OPENING ANGLES AND REST-FRAME ENERGETICS

    Energy Technology Data Exchange (ETDEWEB)

    Goldstein, Adam [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Connaughton, Valerie [Science and Technology Institute, Universities Space Research Association, Huntsville, AL 35805 (United States); Briggs, Michael S.; Burns, Eric, E-mail: adam.m.goldstein@nasa.gov [Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35899 (United States)

    2016-02-10

    We present a method to estimate the jet opening angles of long duration gamma-ray bursts (GRBs) using the prompt gamma-ray energetics and an inversion of the Ghirlanda relation, which is a correlation between the time-integrated peak energy of the GRB prompt spectrum and the collimation-corrected energy in gamma-rays. The derived jet opening angles using this method and detailed assumptions match well with the corresponding inferred jet opening angles obtained when a break in the afterglow is observed. Furthermore, using a model of the predicted long GRB redshift probability distribution observable by the Fermi Gamma-ray Burst Monitor (GBM), we estimate the probability distributions for the jet opening angle and rest-frame energetics for a large sample of GBM GRBs for which the redshifts have not been observed. Previous studies have only used a handful of GRBs to estimate these properties due to the paucity of observed afterglow jet breaks, spectroscopic redshifts, and comprehensive prompt gamma-ray observations, and we potentially expand the number of GRBs that can be used in this analysis by more than an order of magnitude. In this analysis, we also present an inferred distribution of jet breaks which indicates that a large fraction of jet breaks are not observable with current instrumentation and observing strategies. We present simple parameterizations for the jet angle, energetics, and jet break distributions so that they may be used in future studies.

  18. 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.

  19. Conjugando el presente

    Directory of Open Access Journals (Sweden)

    Héctor Rojas Herazo

    1968-06-01

    Full Text Available La añoranza suele ser, casi siempre, la línea critica de menor resistencia. El lema de que "todo tiempo pasado fue mejor" tiene un poco la culpa. En cualquier orden del conocimiento el pasado sigue el verdadero presente. Ese presente en que nos gusta respirar y vivir. Nada de compromiso circundante. Nada de inmediatez.

  20. 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.

  1. 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.

  2. The small angle tile calorimeter in the DELPHI experiment

    CERN Document Server

    Alvsvaag, S J; Barreira, G; Benvenuti, Alberto C; Bigi, M; Bonesini, M; Bozzo, M; Camporesi, T; Carling, H; Cassio, V; Castellani, L; Cereseto, R; Chignoli, F; Della Ricca, G; Dharmasiri, D R; Espirito-Santo, M C; Falk, E; Fenyuk, A; Ferrari, P; Gamba, D; Giordano, V; Guz, Yu; Guerzoni, M; Gumenyuk, S A; Hedberg, V; Jarlskog, G; Karyukhin, A N; Klovning, A; Konoplyannikov, A K; Kronkvist, I J; Lanceri, L; Leoni, R; Maeland, O A; Maio, A; Mazza, R; Migliore, E; Navarria, Francesco Luigi; Negri, P; Nossum, B; Obraztsov, V F; Onofre, A; Paganoni, M; Pegoraro, M; Peralta, L; Petrovykh, L P; Pimenta, M; Poropat, P; Prest, M; Read, A L; Romero, A; Shalanda, N A; Simonetti, L; Skaali, T B; Stugu, B; Terranova, F; Tomé, B; Torassa, E; Trapani, P P; Verardi, M G; Vallazza, E; Vlasov, E; Zaitsev, A

    1999-01-01

    The {\\bf S}mall angle {\\bf TI}le {\\bf C}alorimeter ({\\bf STIC}) provides calorimetric coverage in the very forward region of the DELPHI experiment at the CERN LEP collider. The structure of the calorimeters, built with a so-called ``shashlik'' technique, gives a perfectly hermetic calorimeter and still allows for the insertion of tracking detectors within the sampling structure to measure the direction of the showering particle. A charged-particle veto system, composed of two scintillator layers, makes it possible to trigger on single photon events and provides e-$\\gamma$ separat ion. Results are presented from the extensive studies of these detectors in the CERN testbeams prior to installation and of the detector performance at LEP.

  3. 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.

  4. Wide-angle cherenkov telescope prototype preliminary data

    Science.gov (United States)

    Timofeev, Lev; Anatoly, Ivanov

    2016-07-01

    This report presents an observation method of Cherenkov light from extensive air showers (EAS) generated by cosmic rays (CRs) above 10^16eV and preliminary observations. The interest in Cherenkov light differential detectors of EAS is caused by the possibility to measure the depth of cascade maximum, Xmax, and/or the shower age via angular and temporal distributions of the Cherenkov signal. In particular, it was shown using EAS model simulations that the pulse width measured at the periphery of the shower, r > 300 m, at sea level is pronouncedly connected with Xmax. Cherenkov detector is a wide-angle telescope working in coincidence with scintillation detectors, integral and differential Cherenkov detectors Yakutsk complex EAS.

  5. Angle Class I malocclusion with anterior negative overjet

    Directory of Open Access Journals (Sweden)

    Paulo Ávila de Souza

    2016-04-01

    Full Text Available ABSTRACT This clinical case report describes the orthodontic treatment of an 8-year and 9-month old female patient with Angle Class I malocclusion, anterior crossbite and canine Class III relationship. Orthodontic treatment was carried out in two stages. The first one was orthopedic, while the second one included the use of a fixed appliance and the need for space gain for reshaping of maxillary lateral incisors. The two-stage treatment combined with multidisciplinary Restorative Cosmetic Dentistry allowed excellent esthetic and functional outcomes to be achieved. This case was presented to the Brazilian Board of Orthodontics and Dentofacial Orthopedics (BBO as a requirement for the title of certified by the BBO.

  6. 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.

  7. Dynamic contact angle of water-based titanium oxide nanofluid.

    Science.gov (United States)

    Radiom, Milad; Yang, Chun; Chan, Weng Kong

    2013-06-11

    This paper presents an investigation into spreading dynamics and dynamic contact angle of TiO2-deionized water nanofluids. Two mechanisms of energy dissipation, (1) contact line friction and (2) wedge film viscosity, govern the dynamics of contact line motion. The primary stage of spreading has the contact line friction as the dominant dissipative mechanism. At the secondary stage of spreading, the wedge film viscosity is the dominant dissipative mechanism. A theoretical model based on combination of molecular kinetic theory and hydrodynamic theory which incorporates non-Newtonian viscosity of solutions is used. The model agreement with experimental data is reasonable. Complex interparticle interactions, local pinning of the contact line, and variations in solid-liquid interfacial tension are attributed to errors.

  8. 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.

  9. Magnetic Resonance Velocimetry analysis of an angled impinging jet

    Science.gov (United States)

    Irhoud, Alexandre; Benson, Michael; Verhulst, Claire; van Poppel, Bret; Elkins, Chris; Helmer, David

    2016-11-01

    Impinging jets are used to achieve high heat transfer rates in applications ranging from gas turbine engines to electronics. Despite the importance and relative simplicity of the geometry, simulations historically fail to accurately predict the flow behavior in the vicinity of the flow impingement. In this work, we present results from a novel experimental technique, Magnetic Resonance Velocimetry (MRV), which measures three-dimensional time-averaged velocity without the need for optical access. The geometry considered in this study is a circular jet angled at 45 degrees and impinging on a flat plate, with a separation of approximately seven jet diameters between the jet exit and the impingement location. Two flow conditions are considered, with Reynolds numbers of roughly 800 and 14,000. Measurements from the MRV experiment are compared to predictions from Reynolds Averaged Navier Stokes (RANS) simulations, thus demonstrating the utility of MRV for validation of numerical analyses of impinging jet flow.

  10. Decorative power generating panels creating angle insensitive transmissive colors.

    Science.gov (United States)

    Lee, Jae Yong; Lee, Kyu-Tae; Seo, Sungyong; Guo, L Jay

    2014-02-28

    We present ultra-thin (6 to 31 nm) undoped amorphous silicon/organic hybrid solar cell structure, which can transmit desired color of light. The transmitted colors show great angular tolerance due to the negligible optical phase associated with light propagating in ultra-thin amorphous silicon (a-Si) layers. We achieved the power conversion efficiency of the hybrid cells up to 2 %; and demonstrated that most of the absorbed photons in the undoped a-Si layer contributed to the extracted electric charges due to the suppressed electron-hole recombination in the ultra-thin a-Si layer. We also show the resonance is invariant with respect to the angle of incidence up to ± 70° regardless of the polarization of the incident light. Our exploration provides a design to realize energy harvesting colored photovoltaic panels for innovative applications.

  11. 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

  12. 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.

  13. 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.

  14. Study of the advancing and receding contact angles: liquid sorption as a cause of contact angle hysteresis.

    Science.gov (United States)

    Lam, C N C; Wu, R; Li, D; Hair, M L; Neumann, A W

    2002-02-25

    Two types of experiments were used to study the behavior of both advancing and receding contact angles, namely the dynamic one-cycle contact angle (DOCA) and the dynamic cycling contact angle (DCCA) experiments. For the preliminary study, DOCA measurements of different liquids on different solids were performed using an automated axisymmetric drop shape analysis-profile (ADSA-P). From these experimental results, four patterns of receding contact angle were observed: (1) time-dependent receding contact angle; (2) constant receding contact angle; (3) 'stick/slip'; (4) no receding contact angle. For the purpose of illustration, results from four different solid surfaces are shown. These solids are: FC-732-coated surface; poly(methyl methacrylate/n-butyl methacrylate) [P(MMA/nBMA)]; poly(lactic acid) (DL-PLA); and poly(lactic/glycolic acid) 50/50 (DL-PLGA 50/50). Since most of the surfaces in our studies exhibit time dependence in the receding contact angle, a more extended study was conducted using only FC-732-coated surfaces to better understand the possible causes of decreasing receding contact angle and contact angle hysteresis. Contact angle measurements of 21 liquids from two homologous series (i.e. n-alkanes and 1-alcohols) and octamethylcyclotetrasiloxane (OCMTS) on FC-732-coated surfaces were performed. It is apparent that the contact angle hysteresis decreases with the chain length of the liquid. It was found that the receding contact angle equals the advancing angle when the alkane molecules are infinitely large. These results strongly suggest that the chain length and size of the liquid molecule could contribute to contact angle hysteresis phenomena. Furthermore, DCCA measurements of six liquids from the two homologous series on FC-732-coated surfaces were performed. With these experimental results, one can construe that the time dependence of contact angle hysteresis on relatively smooth and homogeneous surfaces is mainly caused by liquid retention

  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. 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...

  17. 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...

  18. 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

  19. Presenting New Grammar

    Institute of Scientific and Technical Information of China (English)

    WU Cai-ling; WANG Xi

    2015-01-01

    More and more researchers have now agreed upon the necessity of teaching grammar, but it still remains controversial as how to teach the forms, with the central consideration of not to harm the meaning-focused communicative teaching method. In this essay, one of the issues in grammar teaching will be discussed as how to present new grammar to learners, through evaluating and modifying a particular presentation activity in a grammar-teaching textbook.

  20. Blade Testing Trends (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Desmond, M.

    2014-08-01

    As an invited guest speaker, Michael Desmond presented on NREL's NWTC structural testing methods and capabilities at the 2014 Sandia Blade Workshop held on August 26-28, 2014 in Albuquerque, NM. Although dynamometer and field testing capabilities were mentioned, the presentation focused primarily on wind turbine blade testing, including descriptions and capabilities for accredited certification testing, historical methodology and technology deployment, and current research and development activities.

  1. Communication and presentation skills

    OpenAIRE

    Lorencová, Ivana

    2014-01-01

    This bachelor thesis deals with individual factors of communication and basic presentations skills. The theoretical part specifies the basic elements of verbal and non-verbal communication and basic factors connected with preparation and realisation of a presentation. The practical part of the thesis comprises an analysis of impacts of speaker's visual and other communication influences over an audience. The results are applied to a Multimedia Display exhibition taking place during the bachel...

  2. Stellar Presentations (Abstract)

    Science.gov (United States)

    Young, D.

    2015-12-01

    (Abstract only) The AAVSO is in the process of expanding its education, outreach and speakers bureau program. powerpoint presentations prepared for specific target audiences such as AAVSO members, educators, students, the general public, and Science Olympiad teams, coaches, event supervisors, and state directors will be available online for members to use. The presentations range from specific and general content relating to stellar evolution and variable stars to specific activities for a workshop environment. A presentation—even with a general topic—that works for high school students will not work for educators, Science Olympiad teams, or the general public. Each audience is unique and requires a different approach. The current environment necessitates presentations that are captivating for a younger generation that is embedded in a highly visual and sound-bite world of social media, twitter and U-Tube, and mobile devices. For educators, presentations and workshops for themselves and their students must support the Next Generation Science Standards (NGSS), the Common Core Content Standards, and the Science Technology, Engineering and Mathematics (STEM) initiative. Current best practices for developing relevant and engaging powerpoint presentations to deliver information to a variety of targeted audiences will be presented along with several examples.

  3. Effect of contact angle hysteresis on the measurement of capillary forces.

    Science.gov (United States)

    De Souza, E J; Gao, L; McCarthy, T J; Arzt, E; Crosby, A J

    2008-02-19

    We conduct experimental investigations of macroscopic capillary forces between two flat rigid substrates characterized by their advancing and receding contact angles with water. Our results exhibit excellent agreement with theoretical predictions obtained by the numerical solution of the capillary equation. On the basis of this comparison, we use the measurements of the capillary force to investigate the phenomenon of contact angle hysteresis. We present examples of force measurements for surfaces that display low, moderate, and high contact angle hysteresis and compare results for a larger variety of substrates. Finally, we show that for the case of water, the role of viscosity is insignificant within the range of force and velocity measured in the present work.

  4. 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.

  5. [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.

  6. Computer programs for the calculation of dual sting pitch and roll angles required for an articulated sting to obtain angles of attack and sideslip on wind-tunnel models

    Science.gov (United States)

    Peterson, John B., Jr.

    1991-01-01

    Two programs were developed to calculate the pitch and roll position of the conventional sting drive and the pitch of a high angle articulated sting to position a wind tunnel model at the desired angle of attack and sideslip and position the model as near as possible to the centerline of the tunnel. These programs account for the effects of sting offset angles, sting bending angles, and wind-tunnel stream flow angles. In addition, the second program incorporates inputs form on-board accelerometers that measure model pitch and roll with respect to gravity. The programs are presented and a description of the numerical operation of the programs with a definition of the variables used in the programs is given.

  7. Magic angle spinning NMR of paramagnetic proteins.

    Science.gov (United States)

    Knight, Michael J; Felli, Isabella C; Pierattelli, Roberta; Emsley, Lyndon; Pintacuda, Guido

    2013-09-17

    Metal ions are ubiquitous in biochemical and cellular processes. Since many metal ions are paramagnetic due to the presence of unpaired electrons, paramagnetic molecules are an important class of targets for research in structural biology and related fields. Today, NMR spectroscopy plays a central role in the investigation of the structure and chemical properties of paramagnetic metalloproteins, linking the observed paramagnetic phenomena directly to electronic and molecular structure. A major step forward in the study of proteins by solid-state NMR came with the advent of ultrafast magic angle spinning (MAS) and the ability to use (1)H detection. Combined, these techniques have allowed investigators to observe nuclei that previously were invisible in highly paramagnetic metalloproteins. In addition, these techniques have enabled quantitative site-specific measurement of a variety of long-range paramagnetic effects. Instead of limiting solid-state NMR studies of biological systems, paramagnetism provides an information-rich phenomenon that can be exploited in these studies. This Account emphasizes state-of-the-art methods and applications of solid-state NMR in paramagnetic systems in biological chemistry. In particular, we discuss the use of ultrafast MAS and (1)H-detection in perdeuterated paramagnetic metalloproteins. Current methodology allows us to determine the structure and dynamics of metalloenzymes, and, as an example, we describe solid-state NMR studies of microcrystalline superoxide dismutase, a 32 kDa dimer. Data were acquired with remarkably short times, and these experiments required only a few milligrams of sample.

  8. 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.

  9. Apparent contact angle of an evaporating drop

    Science.gov (United States)

    Morris, S. J. S.

    2012-11-01

    In experiments by Poulard et al. (2005), a sessile drop of perfectly wetting liquid evaporates from a non-heated substrate into an under-saturated mixture of vapour with an inert gas; evaporation is limited by vapour diffusion. The system exhibits an apparent contact angle θ that is a flow property. Under certain conditions, the apparent contact line was stationary relative to the substrate; we predict θ for this case. Observed values of θ are small, allowing lubrication analysis of the liquid film. The liquid and vapour flows are coupled through conditions holding at the phase interface; in particular, vapour partial pressure there is related to the local value of liquid pressure through the Kelvin condition. Because the droplet is shallow, the interfacial conditions can be transferred to the solid-liquid interface at y = 0 . We show that the dimensionless partial pressure p (x , y) and the film thickness h (x) are determined by solving ∇2 p = 0 for y > 0 subject to a matching condition at infinity, and the conditions - p = L hxx +h-3 and (h3px) x + 3py = 0 at y = 0 . The parameter L controls the ratio of Laplace to disjoining pressure. We analyse this b.v.p. for the experimentally-relevant case L --> 0 .

  10. Rubber hand illusion affects joint angle perception.

    Directory of Open Access Journals (Sweden)

    Martin V Butz

    Full Text Available The Rubber Hand Illusion (RHI is a well-established experimental paradigm. It has been shown that the RHI can affect hand location estimates, arm and hand motion towards goals, the subjective visual appearance of the own hand, and the feeling of body ownership. Several studies also indicate that the peri-hand space is partially remapped around the rubber hand. Nonetheless, the question remains if and to what extent the RHI can affect the perception of other body parts. In this study we ask if the RHI can alter the perception of the elbow joint. Participants had to adjust an angular representation on a screen according to their proprioceptive perception of their own elbow joint angle. The results show that the RHI does indeed alter the elbow joint estimation, increasing the agreement with the position and orientation of the artificial hand. Thus, the results show that the brain does not only adjust the perception of the hand in body-relative space, but it also modifies the perception of other body parts. In conclusion, we propose that the brain continuously strives to maintain a consistent internal body image and that this image can be influenced by the available sensory information sources, which are mediated and mapped onto each other by means of a postural, kinematic body model.

  11. Angle resolved photoemission spectroscopy and surface states

    Science.gov (United States)

    Kar, Nikhiles

    2016-10-01

    Angle Resolved Photo Emission Spectroscopy (ARPES) has been a very effective tool to study the electronic states of solids, from simple metals to complex systems like cuprate superconductors. For photon energy in the range of 10 - 100 eV, it is a surface sensitive process as the free path of the photo emitted electrons is of the order of a few lattice parameters. However to interpret the experimental data one needs to have a theoretical foundation for the photoemission process. From the theory of photoemission it may be seen that one can get information about the state from which the electron has been excited. As the translational periodicity is broken normal to the surface, a new type of electron state in the forbidden energy gap can exist localized in the surface region. ARPES can reveal the existence and the property of such surface states. We shall also discuss briefly how the electromagnetic field of the photons are influenced by the presence of the surface and how one can try to take that into account in photoemission theory.

  12. 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.

  13. The psychological present.

    Science.gov (United States)

    Hayes, L J

    1992-01-01

    The present paper compares behavior-analytic and cognitive treatments of the concept of psychological history with regard to its role in current action. Both treatments take the position that the past bears some responsibility for the present, and are thereby obligated to find a means of actualizing the past in the present. Both do so by arguing that the past is brought to bear in the present via the organism. Although the arguments of the two positions differ on this issue, neither provides a complete account. An unconventional treatment of psychological history is proposed, the logic of which is exemplified in anthropological, biological, and psychological perspectives. The unconventional treatment in psychological perspective holds that (a) the organism's interaction with its environment, not the organism itself, changes with experience; and (b) the past interactions of an organism exist as, and only as, the present interactions of that organism. This solution to the problem of psychological history provides obligations and opportunities for analysis that are not available when the more conventional positions of cognitivism and behavior analysis are adopted.

  14. TUBERCULOSIS PRESENTING AS EPIGLOTTITIS

    Directory of Open Access Journals (Sweden)

    FAHIM AHMED SHAH

    2015-03-01

    Full Text Available We report a rare case of laryngeal tuberculosis in Oman Tuberculous affection of larynx is un-common in Oman and is rarely been reported. Tuberculosis is a chronic illness, acute clinical presentation is unusual. We report the case of a thirty One year old lady, post renal transplant with tuberculous involvement of the larynx, who presented with symptoms and clinical signs of acute epiglottitis. ENT examination showed initially a severely swollen epiglottis which turned nodular in about two weeks. The patient had been on immunosuppressive medications and glucocorticoids post renal trans-plant. Tuberculosis still presents sporadically in countries where the overall incidence of tuber-culosis is much lower as compared to developing countries. A strong index of suspicion is needed in immunocompromised patients with suboptimal response to routine medications. Diagnostic difficulty in this peculiar situation with differential diagnosis and management of laryngeal tuberculosis is discussed along with review of literature.

  15. 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.

  16. 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.

  17. Variable angle transmittance of silver grid transparent electrodes

    Science.gov (United States)

    Zhao, Yuan-Yuan; Zheng, Mei-Ling; Dong, Xian-Zi; Zhao, Zhen-Sheng; Duan, Xuan-Ming

    2016-10-01

    We focus on investigating the optical transmittance of silver grid transparent electrodes (SGTEs) in variable angle view theoretically and experimentally, rather than the optical transmittance under the normal incidence. The variable angle transmittance (VAT) values of SGTEs are measured on a home-made experimental setup. The experimental results about difference of the transmittance difference under different angles are small and negligible, although the measured angle is changed. Theoretically, the physical mechanism on nearly constant transmittance for different angle view can be well explained according to the theory of geometrical optics. This study provides an approach for investigating the VAT values of SGTEs in a controllable fashion and the influence of viewing angle of the touch screen.

  18. Study of the course of the incidence angle during growth.

    Science.gov (United States)

    Mangione, P; Gomez, D; Senegas, J

    1997-01-01

    Standing posture is made possible by hip extension and lumbar lordosis. Lumbar lordosis is correlated with pelvic parameters, such as the declivity angle of the upper surface of the sacrum and the incidence angle, which determine the sagittal morphotype. Incidence angle, which is different for each individual, is known to be very important for up-right posture, but its course during life has not yet been established. Incidence angle was measured on radiographs of 30 fetuses, 30 children and 30 adults, and results were analysed using the correlation coefficient r and Student's t test. A statistically significant correlation between age and incidence angle was observed. Incidence angle considerably increases during the first months, continues to increase during early years, and stabilizes around the age of 10 years. Incidence is a mark of bipedism, and its role in sagittal balance is essential.

  19. The Earth: Present Scenario

    OpenAIRE

    Nishad Gopal Deshpande

    2009-01-01

    In this article, the present scenario of our motherly loved planet ‘Earth’ is presented. We are living in one of the most developed phases of the Earth’s life cycle. The choices we make today will determine the life on the Earth, tomorrow. Problems that are been created by us and the consequences we are going to face are discussed in length. Some statistical data is provided to get a brief idea. Measure/prevention(s) to combat the upcoming problems have been putforth.

  20. [Atypical presentation of preeclampsia].

    Science.gov (United States)

    Ditisheim, A; Boulvain, M; Irion, O; Pechère-Bertschi, A

    2015-09-09

    Preeclampsia is a pregnancy-related syndrome, which still represents one of the major causes of maternal-fetal mortality and morbidity. Diagnosis can be made difficult due to the complexity of the disorder and its wide spectrum of clinical manifestations. In order to provide an efficient diagnostic tool to the clinician, medical societies regularly rethink the definition criteria. However, there are still clinical presentations of preeclampsia that escape the frame of the definition. The present review will address atypical forms of preeclampsia, such as preeclampsia without proteinuria, normotensive preeclampsia, preeclampsia before 20 weeks of gestation and post-partum preeclampsia.

  1. Book Presentation | 27 February

    CERN Multimedia

    The CERN Library

    2013-01-01

    "A caccia del bosone di Higgs. Magneti, governi, scienziati e particelle nell'impresa scientifica del secolo" by Luciano Maiani and Romeo Bassoli, published by Mondadori. On Wednesday 27 February Luciano Maiani will present the book "A caccia del bosone di Higgs. Magneti, governi, scienziati e particelle nell'impresa scientifica del secolo". More information here. The presentation will take place in the Council Chamber at 16.00 and will be followed by a debate and book signing. The book will be on sale. You are cordially invited.

  2. UPPER LIMITS FOR THE CONTACT ANGLES OF LIQUIDS ON SOLIDS

    Science.gov (United States)

    available on equilibrium contact angles . These data were obtained under well- controlled and comparable experimental conditions for many liquids on...Earlier systematic studies of the angle of contact (theta) exhibited by drops of liquid on plane solid surfaces of low surface energy have made data...From the parameters defining this straight line, estimates can be made of the limiting contact angles for each liquid.

  3. Dynamic contact angle at nano-scale: a unified view

    OpenAIRE

    Lukyanov, Alex V.; Likhtman, Alexei E.

    2016-01-01

    Generation of dynamic contact angle in the course of wetting is a fundamental phenomenon of nature. Dynamic wetting processes have a direct impact on flows at nano-scale, and therefore their understanding is exceptionally important to emerging technologies. Here, we reveal the microscopic mechanism of dynamic contact angle generation. It has been demonstrated using large-scale molecular dynamics simulations of bead-spring model fluids that the main cause of local contact angle variations is t...

  4. Shape, gravity, and the perception of the right angle.

    Science.gov (United States)

    Maniatis, Lydia M

    2010-01-01

    Past efforts to determine whether orientation-dependent sensitivity to right angles is due to retinal or environmental/gravitational frames of reference have produced conflicting conclusions. I attempt to show that the chief factor underlying this phenomenon is, rather, the shape of the object containing the angle. This shape mediates the typical orientation of the object in a ground- gravity context and the consequent force-structure of the incorporated angle-a force structure that is reflected in the percept.

  5. Rotating Shaft Tilt Angle Measurement Using an Inclinometer

    OpenAIRE

    2015-01-01

    This paper describes a novel measurement method to accurately measure the rotating shaft tilt angle of rotating machine for alignment or compensation using a dual-axis inclinometer. A model of the rotating shaft tilt angle measurement is established using a dual-axis inclinometer based on the designed mechanical structure, and the calculation equation between the rotating shaft tilt angle and the inclinometer axes outputs is derived under the condition that the inclinometer axes are perpendic...

  6. 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.

  7. 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...

  8. Presentation design: pecha kucha

    OpenAIRE

    Aníbal, J.

    2011-01-01

    Global presentation phenomena has started in 2003. Pecha Kucha: change in attitude • wonderfully creative • unconventional way “to do PowerPoint". Design is about people creating solutions that help or improve the lives of other people. "Design is not an art although there is art in it", Garr Reynolds.

  9. Neurosyphilis: Various Presentations

    Directory of Open Access Journals (Sweden)

    Kezban Aslan

    2012-12-01

    Full Text Available Neurosphylisis develops in about 5 % of untreated patients infected with Treponema pallidum. Spirocet, disseminates systemically hours to days after inoculation. Early invasion to central nervous system can be seen in infected patients without symptomatic. In these lecture we presented three patients with different complain. The patients have had; diplopia, headache and blurred vision, numness and slimming of legs.

  10. The Persistence of Presentism

    Science.gov (United States)

    Hargreaves, Andy; Shirley, Dennis

    2009-01-01

    Background/Context: This study draws on the voluminous research on teachers' workplace orientations and especially on Dan Lortie's documentation of conservatism, individualism, and presentism among teachers. Purpose/Objective/Research Question/Focus of Study: This study investigated a school reform network of over 300 secondary schools entitled…

  11. Creating Meaningful Multimedia Presentations

    NARCIS (Netherlands)

    Hardman, L.; Ossenbruggen, J.R. van

    2006-01-01

    Finding relevant information is one step in the chain of understanding information. Presenting material to a user in a suitable way is a further step. Our research focuses on using semantic annotations of multimedia elements to increase the ”presentability” of retrieved info

  12. Presentation of 2004 earnings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-03-01

    This presentation offers financial information on the AREVA Group earnings for the year 2004. With manufacturing facilities in over 40 countries and a sales network in over 100, Areva offers customers technological solutions for nuclear power generation and electricity transmission and distribution. The Group also provides interconnect systems to the telecommunications, computer and automotive markets. (A.L.B.)

  13. Generating Embodied Information Presentations

    NARCIS (Netherlands)

    Theune, M.; Heylen, D.; Nijholt, A.; Stock, O.; Zancanaro, M.

    2005-01-01

    The output modalities available for information presentation by embodied, human-like agents include both language and various nonverbal cues such as pointing and gesturing. These human, nonverbal modalities can be used to emphasize, extend or even replace the language output produced by the agent. T

  14. Managing Presentation Anxiety

    Science.gov (United States)

    Hartman, Jackie L.; LeMay, Elaine

    2004-01-01

    All business communication professors struggle with anxiety-ridden students when discussing public speaking. To alleviate students' fears of speaking in public a process was designed to allow business communication students to acknowledge, address, and annul their presentation fears. A six-year comparative study using qualitative methods and…

  15. 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.

  16. Angle Class II correction with MARA appliance

    Directory of Open Access Journals (Sweden)

    Kelly Chiqueto

    2013-02-01

    Full Text Available OBJECTIVE: To assess the effects produced by the MARA appliance in the treatment of Angle's Class II, division 1 malocclusion. METHODS: The sample consisted of 44 young patients divided into two groups: The MARA Group, with initial mean age of 11.99 years, treated with the MARA appliance for an average period of 1.11 years, and the Control Group, with initial mean age of 11.63 years, monitored for a mean period of 1.18 years with no treatment. Lateral cephalograms were used to compare the groups using cephalometric variables in the initial and final phases. For these comparisons, Student's t test was employed. RESULTS: MARA appliance produced the following effects: Maxillary growth restriction, no change in mandibular development, improvement in maxillomandibular relationship, increased lower anterior facial height and counterclockwise rotation of the functional occlusal plane. In the upper arch, the incisors moved lingually and retruded, while the molars moved distally and tipped distally. In the lower arch, the incisors proclined and protruded, whereas the molars mesialized and tipped mesially. Finally, there was a significant reduction in overbite and overjet, with an obvious improvement in molar relationship. CONCLUSIONS: It was concluded that the MARA appliance proved effective in correcting Angle's Class II, division 1 malocclusion while inducing skeletal changes and particularly dental changes.OBJETIVO: avaliar os efeitos proporcionados pelo aparelho MARA no tratamento da má oclusão de Classe II, 1ª divisão. MÉTODOS: utilizou-se uma amostra de 44 jovens, divididos em dois grupos - Grupo MARA, com idade inicial média de 11,99 anos e tratado com o aparelho MARA por um período médio de 1,11 ano; e Grupo Controle, com idade inicial média de 11,63 ano e observado por um período médio de 1,18 ano, sem nenhum tratamento. Utilizou-se as telerradiografias em norma lateral para comparar os grupos quanto às variáveis cefalométricas das

  17. Present status of silicon detectors in COMPASS

    CERN Document Server

    Angerer, H; Esposito, A; Friedrich, J M; Gerassimov, S G; Grube, B; Ketzer, B; Konorov, I; Kühn, R; Paul, S; Schmitt, L; Wagner, R M; Wiesmann, M

    2003-01-01

    In 2002 the COMPASS experiment at CERN has started to take first physics data. The fixed target experiment at the SPS uses muon and hadron beams of very high intensity to investigate the structure of the nucleon. For beam definition and small angle tracking silicon microstrip detectors are used. This article describes the requirements which are set by the physics program of COMPASS for these detectors and the ways they were met, amongst which the operation at a temperature around 130 K (Lazarus effect) is the most prominent. Measurements at low temperatures as well as first results from the operation at room temperature in the COMPASS physics run 2002 are presented.

  18. 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.

  19. 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.

  20. 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.