284 research outputs found
Universal field-tunable terahertz emission by ultrafast photoinduced demagnetization in Fe, Ni, and Co ferromagnetic films
No full textWe report a universal terahertz (THz) emission behavior from simple Ni, Fe, and Co metallic ferromagnetic films, triggered by the femtosecond laser pulse and subsequent photoinduced demagnetization on an ultrafast time scale. THz emission behavior in ferromagnetic films is found to be consistent with initial magnetization states controlled by external fields, where the hysteresis of the maximal THz emission signal is observed to be well-matched with the magnetic hysteresis curve. It is experimentally demonstrated that the ultrafast THz emission by the photoinduced demagnetization is controllable in a simple way by external fields as well as pump fluences. © 2020, The Author(s).1
Surface Oxidation and Wettability of Fe–Mn and Fe–Mn–Si-Alloyed Steel After Annealing
No full textThe surface oxidation and wettability of Mn and Si-alloyed steel after annealing at different conditions are studied with scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and a so-called de-wetting method. After exposure at 950 °C for 1 hour in an Ar + 5 vol pct H2 gas atmosphere with dew points (DP) ranging from – 40 °C to 10 °C, oxides were observed along the grain boundaries or dispersed on the surface for the Fe–1.8 Mn steels while a continuous oxides layer was formed on Fe–1.9 Mn–0.94 Si steels (composition in weight fractions). The oxides formed at different DPs were predicted based on thermodynamic calculations. (Fe,Mn)O was formed on Fe–1.8 Mn steel at the whole range of DPs, while the oxide phase on Fe–1.9 Mn–0.94 Si steel depends on the DP. At low-DP SiO2 were formed and with increasing the DP (Fe,Mn)SiO3 or (Fe,Mn)SiO3 + (Fe,Mn)2SiO4 were formed and finally (Fe,Mn)2SiO4 were formed. An increase of the fraction of Fe in the oxide with increasing DP for both steels was observed with XPS analysis. As a measure for the surface wettability, the contact angle of Pb droplets on the annealed steels surfaces was determined with SEM and image analysis software. Also, the contact angle of Pb on pure Fe and on the Mn and Si alloyed steels free of surface oxides was measured for comparison. The results show that the contact angle of Pb on the steel surfaces after annealing decreases with increasing DP. This improved wettability with increasing dew point is related to the Fe fraction of the oxides formed on the surface.Team Kevin RossiTeam Maria Santofimia NavarroTeam Marcel Herman
Bank presence and health
No full textThis paper demonstrates that increasing bank presence in underserved areas can substantially improve households’ health. I apply a regression discontinuity design to a policy of the Reserve Bank of India. Six years after the policy introduction, treatment districts have 19% more branches than control districts. Households’ probability of suffering from a non-chronic disease in a given month is 36% lower. I show evidence that two understudied aspects of banking play a role: banks provide health insurance to households and credit to hospitals. In equilibrium, I observe an increase in health care demand and supply
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Finance and Development
No full textIn the first chapter of this dissertation, I ask what role bank presence plays in improving health of households. To explore this question, I use a policy of the Reserve Bank of India from 2005 that incentivizes banks to set up new branches in underbanked districts, defined as having a population-to-branch ratio larger than the national average. In a regression discontinuity design, I compare households in districts just above and just below the national average.
Six years after the policy introduction, households in treatment districts are a third less likely to be affected by an illness in a month. They miss fewer days of work or school due to an illness and have lower medical expenses. Ten years after the policy was introduced, I observe persistently lower morbidity rates, higher vaccination rates, and lower risks associated with pregnancies.
I provide evidence that two previously understudied aspects of banking contribute to the effect: households gain access to health insurance and health care providers gain access to credit. In equilibrium, I observe an increase in healthcare demand and supply. In the second chapter of this dissertation, co-authored with Naz Koont, we provide first empirical evidence that consumer peer effects matter for banks’ deposit demand. Using a novel measure that depicts for each county how exposed peers are to a specific bank in a given year, we tightly identify the causal effect of peer exposure on deposit demand through a fixed effects identification strategy. We address key empirical challenges such as time-invariant homophily.
We find that a one percent increase in a bank’s peer exposure leads to a 0.05 percent increase in deposit market share. This effect has become stronger over time with the rise of the internet and social media, which facilitate cross-county communication. Peer exposure is especially relevant for smaller banks and customers that have access to the internet
Bank presence and health
No full textThis article examines whether more bank presence in underserved areas can improve households’ health. Leveraging a 2005 Reserve Bank of India policy and a regression discontinuity design, I demonstrate that 5 years post-policy, treatment districts have twenty-seven more bank branches than control districts. This expansion increases household employment and access to savings accounts, enhancing health investments. On the healthcare supply side, hospitals utilize more credit and expand services. Six years after the policy, households in treatment districts are nineteen percentage points less likely to suffer from non-chronic illnesses in a given month. Chronic diseases remain unaffected
Peer effects in deposit markets
No full textWe provide first empirical evidence that consumer peer effects matter for banks' deposit demand. Using a novel measure that depicts for each county how exposed peers are to a specific bank in a given year, we tightly identify the causal effect of peer exposure on deposit demand through a fixed effects identification strategy. We address key empirical challenges such as time-invariant homophily. We find that a one percent increase in a bank's peer exposure leads to a 0.05 percent increase in deposit market share. This effect has become stronger over time with the rise of the internet and social media, which facilitate cross-county communication. Peer exposure is especially relevant for smaller banks and customers that have access to the internet
Theoretical aspects of spinodal decomposition in Fe-C
No full textCarbon redistribution is known to occur during room temperature aging of Fe-C martensite. One of the proposed mechanisms in the literature by which carbon redistributes is spinodal decomposition, a thermodynamically driven reaction in which the alloy undergoes separation into carbon-rich and carbon-poor regions, giving rise to modulations in carbon concentration. Despite the substantial experimental evidence supporting the occurrence of spinodal decomposition in Fe-C, its theoretical formulation requires attention. In the present study, a theoretical framework based on the regular solution model is built for evaluating the thermodynamics of the Fe-C system, with particular emphasis on the interstitial nature of carbon atoms within the ferrite lattice. Assuming a defect-free lattice, the model explains a miscibility gap in the Fe-C system. The limitations of the current model are critically evaluated.(OLD) MSE-3Materials Science and Engineerin
Absence of significant association of trace elements in nails with urinary KIM-1 biomarker among residents of Addis Ababa in Upper Awash Basin, Ethiopia: a cross-sectional study
No full text\ua9 2022, The Author(s), under exclusive licence to Springer Nature B.V. The Akaki River in the Upper Awash Basin, which flows through Addis Ababa, the capital city of Ethiopia, has been highly polluted by sewage from factories and residential areas. A population-based cross-sectional study was used to assess the association between trace elements and kidney injury from residents living in polluted areas downstream (Akaki-Kality) versus upstream (Gullele) in Sub-Cities of Addis Ababa. A total of 95 individuals (53 from Akaki-Kality and 42 from Gullele) were included in the study. Kidney injury molecule 1 (KIM-1), lead, arsenic, cadmium, cobalt, lead, manganese, zinc, iron, copper, chromium and nickel were evaluated in residents’ urine and nail samples. A large proportion (74%) of the sample population contained KIM-1, including 81% residents in Akaki-Kality and 64% residents in Gullele. KIM-1 was, however, not significantly different (p = 0.05) between the two Sub-Cities, with median of 0.224 ng/mL in Akaki-Kality and 0.152 ng/mL in Gullele. Most of the analyzed elements, except Pb, As, Cd and Co, were found in all of the nail samples, with median (\ub5g/g) in the range of 442‒714 Fe, 97.0‒246 Zn, 11.6‒24.1 Mn, 4.49‒5.85 Cu, 1.46‒1.66 Cr and 1.22‒1.41 Ni. The high incidence of KIM-1 indicates a potential for long term renal tubular damage among residents of the Sub-Cities. The concentrations of the elements in nails were, however, not significantly associated (p = 0.05) with the corresponding levels of KIM-1 in urine. Hence, the observed KIM-1 might be related to exposure to toxic substances or factors other than those included in this study
Estimation of Facial Contact Pressure Based on Finite Element Analysis
No full textA 3D head and face scan data can be usefully applied in the ergonomic design of a wearable product such as an oxygen mask or a virtual reality (VR) headset to support the safety as well as comfort for a certain amount of a target population. This study is aimed to develop analysis and design methods of an ergonomic facial wearable products (e.g., pilot oxygen mask, VR headsets) based on numerous 3D face scan data (366 faces and 2,299 heads) through the template registration and the finite element (FE) analysis methods to predict the contact pressure between the face and a product. The application of the FE analysis on numerous 3D images to find an optimal form of a product is a novel approach in product design. The proposed methods on contact pressure analysis could be usefully applied for wearable products, which fit body parts.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Applied Ergonomics and Desig
Kondo interaction in FeTe and its potential role in the magnetic order
No full textFinding d-electron heavy fermion states has been an important topic as the diversity in d-electron materials can lead to many exotic Kondo effect-related phenomena or new states of matter such as correlation-driven topological Kondo insulator. Yet, obtaining direct spectroscopic evidence for a d-electron heavy fermion system has been elusive to date. Here, we report the observation of Kondo lattice behavior in an antiferromagnetic metal, FeTe, via angle-resolved photoemission spectroscopy, scanning tunneling spectroscopy and transport property measurements. The Kondo lattice behavior is represented by the emergence of a sharp quasiparticle and Fano-type tunneling spectra at low temperatures. The transport property measurements confirm the low-temperature Fermi liquid behavior and reveal successive coherent-incoherent crossover upon increasing temperature. We interpret the Kondo lattice behavior as a result of hybridization between localized Fe 3dxy and itinerant Te 5pz orbitals. Our observations strongly suggest unusual cooperation between Kondo lattice behavior and long-range magnetic order. © 2023. The Author(s).11Nsciescopu
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