Werner Winter - Academia.edu (original) (raw)
Papers by Werner Winter
Clinical Oral Implants Research, 2001
Preliminary to a study investigating the force transfer from osseointegrated dental implants to t... more Preliminary to a study investigating the force transfer from osseointegrated dental implants to the surrounding bone via various types of overdenture attachment, a stereolithographic model (SL-model) was constructed and compared to an in vivo situation in order to confirm the validity of the modeling technique for the planned measurements of implant strain and denture-bearing area loading. The SL-model was generated using the patient's computer tomographic data and duplicated in a material of known elastic properties. The model was fitted with sensors to measure strains in the peri-implant bone and loading forces within the posterior mandibular bone, i.e. the denture-bearing area of the mandible. Special telescopic copings were constructed to measure implant strain in this model as well as in vivo. Using these copings under identical overdenture loading conditions, the strains measured at the implants in vivo and in vitro were the same and never exceeded a tolerance of two standard deviations or a mean difference of ª8.5% of the in vitro value. This indicates that the model was reliable for the measurement of implant strain. Denture-bearing area loading within the alveolar ridge cannot be measured in vivo. Instead, a method of extrapolating in vivo denturebearing area loading figures from implant strain readings was developed and tested (better than 90% accuracy). These in vivo extrapolated figures were then compared to in vitro readings under otherwise identical loading conditions. The result indicated that the SL-model is reliable for measurements of denture-bearing area loading with an error of 10 to 20%.
Ingenieur-Archiv, 1988
Das WerkstoffverhMten vielkrista]liner Materialien wurde in [1] dutch elastisch-plastische Stabwe... more Das WerkstoffverhMten vielkrista]liner Materialien wurde in [1] dutch elastisch-plastische Stabwerke mit kinematischer Verfestigung modelliert. Wir konnten zeigen, dab das bei der (Kurzzeit-) Ermiidung (Low-cycle fatigue) makroskopisch beobachtbare Werkstoffverhalten schon an einem einfachen, statiseh fiberbestimmten Stabwerk simuliert werden kann. Neben der Akkumulation von Eigenspannungen [1] beobachtet man bei groBen Stabwerksverformungen aueh zyklische Ver-und Entfestigungserscheinungen mit sehlagartiger Entfestigung (Bruchversagen). Bei zweiparametriger Beanspruehung lassen sich allein durch Umkehrung der Vorspannung unterschiedliche Effekte hinsichtlich des Versagens bzw. der Dauerfestigkeit erzeugen. Auch treten jetzt Erscheinungen auf, die dem vom Torsionsversuch her bekannten Poynting-bzw. Ronay-Effekt entspreehen. Der Vergleich yon Rechenergebnissen mit elastisch-plastischen Modellstabwerken l~Bt erkennen, dab Stabwerke bei groBen Ver~ormungen aul~erordentlich empfindlich gegenfiber FlieSgrenzenunterschieden der Einzelsti~be bei Zug und Druck reagieren (materieller Bauschinger-Effekt). Elastic-plastic trusses with kinematic hardening as a model lor polyerystalline materials under cyclic loading. Part 2: Cyclic hardening Summary: The behaviour of polycrystalline materials including kinematic hardening was modelled in [1] by means of elastic-plastic trusses. We have shown that already simple, statically non-determined trusses simulate effects well known as low-cycle fatigue. Besides the accumulation of residual stresses [1] we observe for large deformation of the trusses, also cyclic hardening and softening, or even an abrupt softening (failure by crack). An opposite sign of the statical pre-stress may lead to a completely different behaviour with respect to shake-down or fatigue strength. We also obtain phenomena similar to the Poynting-and Ronayeffect well known from the torsion test. Comparing the theoretical results with experiments we recognize that trusses are highly sensitive to differences of the yield limits of the rods, with respect to extension or compression, respectively (material Bauschinger-effect).
Archive of Applied Mechanics (Ingenieur Archiv), 2003
A theory of plasticity is proposed for cellular metals to describe their elastic-plastic transiti... more A theory of plasticity is proposed for cellular metals to describe their elastic-plastic transition zone at small strain. Under certain conditions, only a plane strain test is necessary to determine the yield surface. The method to derive the elastic-plastic behaviour [14, 15] was originally proposed for classical metals. A simple cubic model of a cellular metal is used to demonstrate the method by the finite element method. Recommendations for the numerical simulation are given. The influence of the relative density and the hardening behaviour of the cell wall material is investigated.
Materialwissenschaft und Werkstofftechnik, 2000
Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry, 1981
Tricarbonyl(1,2-di-tert-butyl-3,4,5,6-tetramethylbenzocyclobutadiene)iron, C23H30FeO3, is monocli... more Tricarbonyl(1,2-di-tert-butyl-3,4,5,6-tetramethylbenzocyclobutadiene)iron, C23H30FeO3, is monoclinic, P21/c, Z = 4, with a = 9.279 (3), b = 16.400 (3), c = 16.070 (3) A, fl = 120.10(2) °. Final R = 0.048 for 4656 observed reflections. The tricarbonyliron group coordinates in a tetrahapto mode to the four-membered ring, but the complex may not be regarded as a pure cyclobutadiene complex, because the Fe atom is shifted away from the middle above the four-membered ring, indicating a tendency of the benzene ring to retain some of its resonance energy. The structure of the complexed benzocyclobutadiene moiety is compared with that of the uncomplexed ligand.
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1998
Studying the structural and photoluminescence properties of pseudomorphic Si 1Ϫy C y and Si 1ϪxϪy... more Studying the structural and photoluminescence properties of pseudomorphic Si 1Ϫy C y and Si 1ϪxϪy Ge x C y multiple quantum well ͑QW͒ structures on ͑001͒ Si substrates offer a quantitative characterization of the band gap and band offset shifts caused by C alloying for yϽ3%. The main features of Si 1Ϫy C y alloys, which are a reduced lattice constant and a strong lowering of the conduction band energy, promise that C may serve as a counterpart to Ge in Si heteroepitaxy. The photoluminescent properties of Si 1Ϫy C y and SiGeC QWs are comparable to SiGe. Novel pseudomorphic Si 1Ϫy C y /SiGe coupled QW structures and Si 1Ϫy C y /Ge quantum dot structures result in a strong enhancement of the photoluminescent efficiency. The ternary SiGeC material system offers a higher degree of freedom in strain and band edge engineering of structures. We focus on our recent results on Si 1Ϫy C y and SiGeC QW layers embedded in Si concerning the growth by solid-source molecular beam epitaxy, structural properties, thermal stability, optical properties, and band offsets. The prospects of SiGeC alloys for realization of optoelectronic structures are discussed. First characteristics from 0.75 m p-channel modulation-doped field-effect transistor devices containing an active SiGeC layer demonstrate good electrical properties.
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz, 2003
HNO, 2005
... to tal in far zier ten War thin-Tu mor. So wohl im aus ge dehn ten Ent zün dungsa re-al als a... more ... to tal in far zier ten War thin-Tu mor. So wohl im aus ge dehn ten Ent zün dungsa re-al als auch in tra lu mi nal im vi tal er hal te nen War thin-Tu mor an teil fan den sich nicht dop-pel bre chen de Kris tal le. Un ter Ab wä gung ...
Archiv für klinische und experimentelle Dermatologie, Jan 17, 1965
Medizinische Klinik (Munich, Germany : 1983), Jan 19, 1958
Tropenmedizin und Parasitologie, 1978
Large quantities of Toxoplasma gondii were cultivated in human larynx carcinoma cells (H.Ep 2, he... more Large quantities of Toxoplasma gondii were cultivated in human larynx carcinoma cells (H.Ep 2, heteroploid). Virulent Toxoplasma gondii, strain RH, which were obtained from the peritoneal exsudate of mice 2 days after infection served as inoculum. As culture medium for the cells and for growth medium, Minimum Essential Medium (MEM) supplemented by 5% foetal calf serum and 200,000 IE/1 Penicillin plus 20 mg/1 Sulmycin was used. 2--3 days after inoculation, 150--200 times the amount of the inoculated Toxoplasmas could be harvested in one or several harvests.
Wiederverkaufskultur im Internet, 2011
Im Schwerpunkt der Aktivitäten zur Intensivierung des Gebrauchtwarenhandels und zum Aufbau nachha... more Im Schwerpunkt der Aktivitäten zur Intensivierung des Gebrauchtwarenhandels und zum Aufbau nachhaltiger Handelskulturen standen fünf Leitfragen: 1. Welche Gruppen von Konsumenten nutzen den Gebrauchtwarenhandel mit dem Ergebnis, dass sie letztlich ...
Acta Hydrochimica et Hydrobiologica, 1985
Eight urea herbicides, as are used for weed control, are investigated for their effect on the gre... more Eight urea herbicides, as are used for weed control, are investigated for their effect on the green alga Ankistrodesmus falcatus and the warm-water fish Poecilia reticulata and found to be highly toxic for the test alga or highly to moderately toxic for the fish. If other criteria (acute toxicity to warm-blooded animals, carcinogenicity and biochemical degradability) are taken into account too, the tested herbicides have to be classified as very dangerous water pollutants. Legal sanctions to be applied in cases of exceeded limiting values are discussed.
The growing share of electricity generated from intermittent renewable energy sources as well as ... more The growing share of electricity generated from intermittent renewable energy sources as well as increasing market-based cross-border flows and related physical flows are leading to rising uncertainties in transmission network operation. This paper presents the current and possible future operational challenges from TSOs’ experiences, and provides a comprehensive overview of expected features that a toolbox should contain for the stable operation of the transmission network. In addition, it outlines the research vision of the UMBRELLA project, namely better use of renewable energy forecasts, optimization of transmission system operation, and risk-based security assessment, as the possible solution to tackle the aforementioned challenges. In the end, a brief introduction to the UMBRELLA project has been incorporated.
Thin Solid Films, 2000
Stranski-Krastanov growth in molecular beam epitaxy allows the preparation of self assembling InA... more Stranski-Krastanov growth in molecular beam epitaxy allows the preparation of self assembling InAs and InP quantum dots on GaAs and Ga0,521no,4,P buffer layers, respectively. InAs dots in GaAs prepared by slow growth rates and low temperature overgrowth provide intense photoluminescence at the technologically important wavelength of 1.3 p,m at room temperature. Strain induced vertical alignment, size modification and material interdiffusion for stacked dot layers are studied. A blue shift of the ground state transition energy is observed for the slowly deposited stacked InAs dots. This is ascribed to enhanced strain driven intermixing in vertically aligned islands. For very small densely stacked InP and InAs dots the reduced confinement shift causes a red shift of the ground state emission. The InP quantum dots show intense and narrow photoluminescence at room temperature in the visible red spectral range. First InP/Ga0,521no,4,P quantum dot injection lasers are prepared using threefold stacked InP dots. We observe lasing at room temperature in the wavelength range between 690-705 nm depending on the size of the stacked InP dots.
Semiconductors, 2001
ABSTRACT The transition from closed to open electron orbits in a magnetic field has been studied ... more ABSTRACT The transition from closed to open electron orbits in a magnetic field has been studied by polarized hot electron photoluminescence (HEPL) in superlattices with varied widths of electron minibands. The dependence of the HEPL depolarization on the miniband width is observed. The strong depolarization occurring when the kinetic energy of electrons exceeds the energy gap between the minibands is interpreted in terms of a magnetic-field-induced transition between the electron minibands (magnetic breakdown).
Physical Review D, 2007
We discuss the physics of superbeam upgrades, where we focus on T2KK, a NuMI beam line based expe... more We discuss the physics of superbeam upgrades, where we focus on T2KK, a NuMI beam line based experiment NOνA*, and a wide band beam (WBB) experiment independent of the NuMI beam line. For T2KK, we find that the Japan-Korea baseline helps resolve parameter degeneracies, but the improvement due to correlated systematics between the two detectors (using identical detectors) is only moderate. For an upgrade of NOνA with a liquid argon detector, we demonstrate that the Ash River site is preferred compared to alternatives, such as at the second oscillation maximum, and is the optimal site within the U.S. For a WBB experiment, we find that high proton energies and long decay tunnels are preferable. We compare water Cherenkov and liquid argon technologies, and find the break-even point in detector cost at about 4:1. In order to compare the physics potential of the different experimental configurations, we use the concept of exposure to normalize the performance. We find that experiments with WBBs are the best experimental concept. NOνA* could be competitive with sufficient luminosity. If sin 2 2θ 13 > 0.01, a WBB experiment can perform better than a neutrino factory.
Nuclear Physics A, 2003
The neutrino spectrum from the decay of 8B is a crucial ingredient in interpreting recent data fr... more The neutrino spectrum from the decay of 8B is a crucial ingredient in interpreting recent data from solar neutrino detectors. Since 8B decays to a broad state in 8Be, the shape of the neutrino spectrum is best obtained from a measurement of the α spectrum following the β+ decay. A new technique has been used at the ATLAS accelerator to
Journal of Urban Affairs, 2013
This paper uses the "civic capacity" framework to analyze an emerging schoolcommunity reform init... more This paper uses the "civic capacity" framework to analyze an emerging schoolcommunity reform initiative, called 24:1, focused on an inner-ring suburban school district. Contrary to the existing literature on civic capacity, we argue that institutions strongly influence civic capacity building. A fragmented public sector and weak institutions of civil society, especially when combined with racial divisions and poverty, restrict the ability of local actors to collaborate among themselves and partner with outside institutions. Despite these daunting challenges, 24:1, led by a local nonprofit with a long history in the area and a school district with dynamic new leadership, has mobilized a diverse coalition of stakeholders and built consensus around a comprehensive plan for revitalization. But stronger indigenous institutions, as well as greater support from the business community, will be needed to sustain the initiative.
Clinical Oral Implants Research, 2001
Preliminary to a study investigating the force transfer from osseointegrated dental implants to t... more Preliminary to a study investigating the force transfer from osseointegrated dental implants to the surrounding bone via various types of overdenture attachment, a stereolithographic model (SL-model) was constructed and compared to an in vivo situation in order to confirm the validity of the modeling technique for the planned measurements of implant strain and denture-bearing area loading. The SL-model was generated using the patient's computer tomographic data and duplicated in a material of known elastic properties. The model was fitted with sensors to measure strains in the peri-implant bone and loading forces within the posterior mandibular bone, i.e. the denture-bearing area of the mandible. Special telescopic copings were constructed to measure implant strain in this model as well as in vivo. Using these copings under identical overdenture loading conditions, the strains measured at the implants in vivo and in vitro were the same and never exceeded a tolerance of two standard deviations or a mean difference of ª8.5% of the in vitro value. This indicates that the model was reliable for the measurement of implant strain. Denture-bearing area loading within the alveolar ridge cannot be measured in vivo. Instead, a method of extrapolating in vivo denturebearing area loading figures from implant strain readings was developed and tested (better than 90% accuracy). These in vivo extrapolated figures were then compared to in vitro readings under otherwise identical loading conditions. The result indicated that the SL-model is reliable for measurements of denture-bearing area loading with an error of 10 to 20%.
Ingenieur-Archiv, 1988
Das WerkstoffverhMten vielkrista]liner Materialien wurde in [1] dutch elastisch-plastische Stabwe... more Das WerkstoffverhMten vielkrista]liner Materialien wurde in [1] dutch elastisch-plastische Stabwerke mit kinematischer Verfestigung modelliert. Wir konnten zeigen, dab das bei der (Kurzzeit-) Ermiidung (Low-cycle fatigue) makroskopisch beobachtbare Werkstoffverhalten schon an einem einfachen, statiseh fiberbestimmten Stabwerk simuliert werden kann. Neben der Akkumulation von Eigenspannungen [1] beobachtet man bei groBen Stabwerksverformungen aueh zyklische Ver-und Entfestigungserscheinungen mit sehlagartiger Entfestigung (Bruchversagen). Bei zweiparametriger Beanspruehung lassen sich allein durch Umkehrung der Vorspannung unterschiedliche Effekte hinsichtlich des Versagens bzw. der Dauerfestigkeit erzeugen. Auch treten jetzt Erscheinungen auf, die dem vom Torsionsversuch her bekannten Poynting-bzw. Ronay-Effekt entspreehen. Der Vergleich yon Rechenergebnissen mit elastisch-plastischen Modellstabwerken l~Bt erkennen, dab Stabwerke bei groBen Ver~ormungen aul~erordentlich empfindlich gegenfiber FlieSgrenzenunterschieden der Einzelsti~be bei Zug und Druck reagieren (materieller Bauschinger-Effekt). Elastic-plastic trusses with kinematic hardening as a model lor polyerystalline materials under cyclic loading. Part 2: Cyclic hardening Summary: The behaviour of polycrystalline materials including kinematic hardening was modelled in [1] by means of elastic-plastic trusses. We have shown that already simple, statically non-determined trusses simulate effects well known as low-cycle fatigue. Besides the accumulation of residual stresses [1] we observe for large deformation of the trusses, also cyclic hardening and softening, or even an abrupt softening (failure by crack). An opposite sign of the statical pre-stress may lead to a completely different behaviour with respect to shake-down or fatigue strength. We also obtain phenomena similar to the Poynting-and Ronayeffect well known from the torsion test. Comparing the theoretical results with experiments we recognize that trusses are highly sensitive to differences of the yield limits of the rods, with respect to extension or compression, respectively (material Bauschinger-effect).
Archive of Applied Mechanics (Ingenieur Archiv), 2003
A theory of plasticity is proposed for cellular metals to describe their elastic-plastic transiti... more A theory of plasticity is proposed for cellular metals to describe their elastic-plastic transition zone at small strain. Under certain conditions, only a plane strain test is necessary to determine the yield surface. The method to derive the elastic-plastic behaviour [14, 15] was originally proposed for classical metals. A simple cubic model of a cellular metal is used to demonstrate the method by the finite element method. Recommendations for the numerical simulation are given. The influence of the relative density and the hardening behaviour of the cell wall material is investigated.
Materialwissenschaft und Werkstofftechnik, 2000
Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry, 1981
Tricarbonyl(1,2-di-tert-butyl-3,4,5,6-tetramethylbenzocyclobutadiene)iron, C23H30FeO3, is monocli... more Tricarbonyl(1,2-di-tert-butyl-3,4,5,6-tetramethylbenzocyclobutadiene)iron, C23H30FeO3, is monoclinic, P21/c, Z = 4, with a = 9.279 (3), b = 16.400 (3), c = 16.070 (3) A, fl = 120.10(2) °. Final R = 0.048 for 4656 observed reflections. The tricarbonyliron group coordinates in a tetrahapto mode to the four-membered ring, but the complex may not be regarded as a pure cyclobutadiene complex, because the Fe atom is shifted away from the middle above the four-membered ring, indicating a tendency of the benzene ring to retain some of its resonance energy. The structure of the complexed benzocyclobutadiene moiety is compared with that of the uncomplexed ligand.
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1998
Studying the structural and photoluminescence properties of pseudomorphic Si 1Ϫy C y and Si 1ϪxϪy... more Studying the structural and photoluminescence properties of pseudomorphic Si 1Ϫy C y and Si 1ϪxϪy Ge x C y multiple quantum well ͑QW͒ structures on ͑001͒ Si substrates offer a quantitative characterization of the band gap and band offset shifts caused by C alloying for yϽ3%. The main features of Si 1Ϫy C y alloys, which are a reduced lattice constant and a strong lowering of the conduction band energy, promise that C may serve as a counterpart to Ge in Si heteroepitaxy. The photoluminescent properties of Si 1Ϫy C y and SiGeC QWs are comparable to SiGe. Novel pseudomorphic Si 1Ϫy C y /SiGe coupled QW structures and Si 1Ϫy C y /Ge quantum dot structures result in a strong enhancement of the photoluminescent efficiency. The ternary SiGeC material system offers a higher degree of freedom in strain and band edge engineering of structures. We focus on our recent results on Si 1Ϫy C y and SiGeC QW layers embedded in Si concerning the growth by solid-source molecular beam epitaxy, structural properties, thermal stability, optical properties, and band offsets. The prospects of SiGeC alloys for realization of optoelectronic structures are discussed. First characteristics from 0.75 m p-channel modulation-doped field-effect transistor devices containing an active SiGeC layer demonstrate good electrical properties.
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz, 2003
HNO, 2005
... to tal in far zier ten War thin-Tu mor. So wohl im aus ge dehn ten Ent zün dungsa re-al als a... more ... to tal in far zier ten War thin-Tu mor. So wohl im aus ge dehn ten Ent zün dungsa re-al als auch in tra lu mi nal im vi tal er hal te nen War thin-Tu mor an teil fan den sich nicht dop-pel bre chen de Kris tal le. Un ter Ab wä gung ...
Archiv für klinische und experimentelle Dermatologie, Jan 17, 1965
Medizinische Klinik (Munich, Germany : 1983), Jan 19, 1958
Tropenmedizin und Parasitologie, 1978
Large quantities of Toxoplasma gondii were cultivated in human larynx carcinoma cells (H.Ep 2, he... more Large quantities of Toxoplasma gondii were cultivated in human larynx carcinoma cells (H.Ep 2, heteroploid). Virulent Toxoplasma gondii, strain RH, which were obtained from the peritoneal exsudate of mice 2 days after infection served as inoculum. As culture medium for the cells and for growth medium, Minimum Essential Medium (MEM) supplemented by 5% foetal calf serum and 200,000 IE/1 Penicillin plus 20 mg/1 Sulmycin was used. 2--3 days after inoculation, 150--200 times the amount of the inoculated Toxoplasmas could be harvested in one or several harvests.
Wiederverkaufskultur im Internet, 2011
Im Schwerpunkt der Aktivitäten zur Intensivierung des Gebrauchtwarenhandels und zum Aufbau nachha... more Im Schwerpunkt der Aktivitäten zur Intensivierung des Gebrauchtwarenhandels und zum Aufbau nachhaltiger Handelskulturen standen fünf Leitfragen: 1. Welche Gruppen von Konsumenten nutzen den Gebrauchtwarenhandel mit dem Ergebnis, dass sie letztlich ...
Acta Hydrochimica et Hydrobiologica, 1985
Eight urea herbicides, as are used for weed control, are investigated for their effect on the gre... more Eight urea herbicides, as are used for weed control, are investigated for their effect on the green alga Ankistrodesmus falcatus and the warm-water fish Poecilia reticulata and found to be highly toxic for the test alga or highly to moderately toxic for the fish. If other criteria (acute toxicity to warm-blooded animals, carcinogenicity and biochemical degradability) are taken into account too, the tested herbicides have to be classified as very dangerous water pollutants. Legal sanctions to be applied in cases of exceeded limiting values are discussed.
The growing share of electricity generated from intermittent renewable energy sources as well as ... more The growing share of electricity generated from intermittent renewable energy sources as well as increasing market-based cross-border flows and related physical flows are leading to rising uncertainties in transmission network operation. This paper presents the current and possible future operational challenges from TSOs’ experiences, and provides a comprehensive overview of expected features that a toolbox should contain for the stable operation of the transmission network. In addition, it outlines the research vision of the UMBRELLA project, namely better use of renewable energy forecasts, optimization of transmission system operation, and risk-based security assessment, as the possible solution to tackle the aforementioned challenges. In the end, a brief introduction to the UMBRELLA project has been incorporated.
Thin Solid Films, 2000
Stranski-Krastanov growth in molecular beam epitaxy allows the preparation of self assembling InA... more Stranski-Krastanov growth in molecular beam epitaxy allows the preparation of self assembling InAs and InP quantum dots on GaAs and Ga0,521no,4,P buffer layers, respectively. InAs dots in GaAs prepared by slow growth rates and low temperature overgrowth provide intense photoluminescence at the technologically important wavelength of 1.3 p,m at room temperature. Strain induced vertical alignment, size modification and material interdiffusion for stacked dot layers are studied. A blue shift of the ground state transition energy is observed for the slowly deposited stacked InAs dots. This is ascribed to enhanced strain driven intermixing in vertically aligned islands. For very small densely stacked InP and InAs dots the reduced confinement shift causes a red shift of the ground state emission. The InP quantum dots show intense and narrow photoluminescence at room temperature in the visible red spectral range. First InP/Ga0,521no,4,P quantum dot injection lasers are prepared using threefold stacked InP dots. We observe lasing at room temperature in the wavelength range between 690-705 nm depending on the size of the stacked InP dots.
Semiconductors, 2001
ABSTRACT The transition from closed to open electron orbits in a magnetic field has been studied ... more ABSTRACT The transition from closed to open electron orbits in a magnetic field has been studied by polarized hot electron photoluminescence (HEPL) in superlattices with varied widths of electron minibands. The dependence of the HEPL depolarization on the miniband width is observed. The strong depolarization occurring when the kinetic energy of electrons exceeds the energy gap between the minibands is interpreted in terms of a magnetic-field-induced transition between the electron minibands (magnetic breakdown).
Physical Review D, 2007
We discuss the physics of superbeam upgrades, where we focus on T2KK, a NuMI beam line based expe... more We discuss the physics of superbeam upgrades, where we focus on T2KK, a NuMI beam line based experiment NOνA*, and a wide band beam (WBB) experiment independent of the NuMI beam line. For T2KK, we find that the Japan-Korea baseline helps resolve parameter degeneracies, but the improvement due to correlated systematics between the two detectors (using identical detectors) is only moderate. For an upgrade of NOνA with a liquid argon detector, we demonstrate that the Ash River site is preferred compared to alternatives, such as at the second oscillation maximum, and is the optimal site within the U.S. For a WBB experiment, we find that high proton energies and long decay tunnels are preferable. We compare water Cherenkov and liquid argon technologies, and find the break-even point in detector cost at about 4:1. In order to compare the physics potential of the different experimental configurations, we use the concept of exposure to normalize the performance. We find that experiments with WBBs are the best experimental concept. NOνA* could be competitive with sufficient luminosity. If sin 2 2θ 13 > 0.01, a WBB experiment can perform better than a neutrino factory.
Nuclear Physics A, 2003
The neutrino spectrum from the decay of 8B is a crucial ingredient in interpreting recent data fr... more The neutrino spectrum from the decay of 8B is a crucial ingredient in interpreting recent data from solar neutrino detectors. Since 8B decays to a broad state in 8Be, the shape of the neutrino spectrum is best obtained from a measurement of the α spectrum following the β+ decay. A new technique has been used at the ATLAS accelerator to
Journal of Urban Affairs, 2013
This paper uses the "civic capacity" framework to analyze an emerging schoolcommunity reform init... more This paper uses the "civic capacity" framework to analyze an emerging schoolcommunity reform initiative, called 24:1, focused on an inner-ring suburban school district. Contrary to the existing literature on civic capacity, we argue that institutions strongly influence civic capacity building. A fragmented public sector and weak institutions of civil society, especially when combined with racial divisions and poverty, restrict the ability of local actors to collaborate among themselves and partner with outside institutions. Despite these daunting challenges, 24:1, led by a local nonprofit with a long history in the area and a school district with dynamic new leadership, has mobilized a diverse coalition of stakeholders and built consensus around a comprehensive plan for revitalization. But stronger indigenous institutions, as well as greater support from the business community, will be needed to sustain the initiative.