5,412 research outputs found
Lateral Inverse Proximity Effect in Ti/Au Transition Edge Sensors
No full textWe report measured Tc of superconducting Ti/Au bilayer strips with a width W varying from 5 to 50 µm. The strips were fabricated based on a Ti/Au bilayer that consists of a 41-nm-thick Ti layer to which a 280-nm-thick Au layer was added. We find that the Tc drops as W decreases and the declining trend almost perfectly follows Tc/ [mK] = - 738.4 [μ m] 2/ W2+ 91.0 , where Tc(W= ∞) of 91 mK is consistent with the intrinsic Tc of the bilayer. The result is interpreted as a consequence of the lateral inverse proximity effect originated in normal-metal microstructures, namely Au overhangs that exist at the edges of the Ti/Au bilayer. The Tc shift from the intrinsic Tc should be anticipated in addition to the longitudinal proximity effect from superconducting Nb leads when one designs Ti/Au TESs.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.ImPhys/Optic
Revealing the influence of Mo addition on interphase precipitation in Ti-bearing low carbon steels
No full textMo is widely used as an effective microalloying element to improve mechanical performance of interphase precipitation steels, but the precise role of Mo in interphase precipitation behavior is not fully understood. In this contribution, interphase precipitation behavior in a series of Ti-Mo-bearing low carbon steels is systematically studied, and the role of Mo in interphase precipitates and its coarsening behavior is revisited. It is found that (Ti, Mo)C precipitates instead of TiC are formed in the Mo-containing alloys, and the average site fraction of Mo in (Ti, Mo)C is almost independent of the bulk Mo content. Moreover, the number density of interphase precipitates can be substantially enhanced by a minor addition of Mo, albeit it does not further rise with increasing the bulk Mo content. This is because the Mo fraction in (Ti, Mo)C rather than the bulk Mo content governs the driving force for precipitation nucleation and the interfacial energy of the (Ti, Mo)C/α and (Ti, Mo)C/γ interfaces. In addition to the reduced interfacial energy, decrease of Ti trans-interface diffusivity has been identified as another key reason for the enhanced carbide coarsening resistance in Mo-containing alloys.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.Novel Aerospace Material
The Structure and Photocatalytic Function of Hydroxyapatite with Doped Ti (IV) Ion
No full textP(論文)Hydroxyapatite (HAp) has a molecular structure in which Ca^, PO_4^ and OH^- are major components. When hydroxyapatite is formed the Ca^, PO_4^ and OH^- ions can be substituted with other specific ions. When a specific ion is purposely replaced in the forming hydroxyapatite crystal, there is a possibility that the new hydroxyapatite might demonstrate properties that could be attributed to the substituted ion. This change in hydroxyapatite properties has been demonstrated when F^- has been substituted for OH^-, F^- has significant acid resistance. The acid resistance property of F^- was observed when F^- was substituted for OH^- in hydroxyapatite. Therefore, the author performed the following experiment : The first portion of the experiment was the synthesis of HAp using the coprecipitation method substituting Ti^ for Ca^. The Ti^ was doped to the Ca^ position in the forming hydroxyapatite crystal. In the next phase of this experiment the author analyzed whether the HAp had obtained photocatalytic function that is a major character of Ti^. HAp using the coprecipitation method was synthesized with different concentrations of Ti^. Respectively the HAp was prepared with Ti^ concentrations of 0.01, 0.005, 0.0025 and 0 moles. The determination of the elementary composition of the synthesized TiHAp was investigated with ICP analysis. The structure of the TiHAp crystal was also investigated by X-ray diffraction. The TiHAp was irradiated by ultraviolet light to determine and measure the presence of photocatalytic function. The formation of radicals and their strength were also measured by ESR spin trapping. A specimen was prepared with 1% TiHAp combined with polypropylene and a second specimen was prepared with 1% TiHAp combined acrylic denture base resins. These specimens were then investigated by a facilitated deterioration exposure test. The photocatalytic function of each specimen was also investigated. The following conclusions of the experiment were obtained : 1. The X-ray diffraction of the TiHAp showed a. reversed correlative phenomenon when anatase dioxide titanium was at 25° (2θ) and the peak strength of HAp was at 26° (2θ) due to the doped Ti^. Therefore, the observed change in the HAp must be a consequence of the doped Ti^ into the HAp molecule. The mole ratio of the Ca/P in the synthetic substance showed that the Ti^ concentration was dependent on the successful doping of Ti^ for Ca^. It was observed that the more successful the dope of Ti^ for Ca^ the mole ratio showed a rectilinear decrease. Therefore, this observation confirmed that Ti^ had replaced Ca^. 2. The OH radical was identified from the post ultraviolet irradiated synthesized substance. The strength of the OH radical increased when the success of the substitution of Ti^ for Ca^ increased. 3. The observation of a clear OH radical signal by ultraviolet irradiation was confirmed from the outer layers of both the polypropylene and acrylic denture base resins that had been combined with 1 % of the synthesized TiHAp. It was observed that there was delayed depletion in the resins that had been combined with the synthesized TiHAp. The results of this experiment provided these conclusions : When a desired concentration of Ti^ has been successfully substituted for Ca^ in a synthesized hydroxyapatite crystal the newly synthesized HAp obtained photocatalytic function that is a special characteristic of titanium.departmental bulletin pape
Inbound and outbound trucks scheduling at crossdocks:
No full textIn today’s customer driven economy, moving products quickly, efficiently, and cost effectively offers crucial advantages to companies. To achieve these goals, more and more companies are finding that cross-docking can play an integral part in their distribution model by partially replacing or complementing existing warehousing facilities. Crossdocking is a material handling and distribution operation, which moves products quickly and directly from inbound trucks (ITs) to outbound trucks (OTs) through the crossdock facility where products are being resorted or consolidated, without being stored or only with a short-term storage, usually within 24 hours or sometimes only within one hour.
This research deals with the scheduling of both ITs and OTs at a crossdocking facility where three objectives are considered: The first objective is to minimize the starting and handling time of all ITs; the second objective is to minimize the total weighted distance of pallets traveled inside the crossdock facility; and the third objective is to minimize the total departure time of all OTs. Multi-objective mixed-integer program formulations are built in order to address the problem. Justification for the use of these objectives in optimizing cross-dock operations is given. Different models are built for three different door layouts at crossdocking facility.
Since the problems are NP-hard, we consider the problem size limitations to obtain an exact solution. In addition, a restriction-approximation approach to solve the models is proposed and the efficiency of our approximation method is proved based on generated data. Finally, numerical examples are provided using the mathematical models built and the approximation approaches. Results for different layouts and scenarios are compared to evaluate the characteristics of different crossdock layouts.M.S.Includes bibliographical references (p. 129-133)by Ti Zhan
Microstructure in rapidly solidified Al-Ti-Si and Al-Ti-Fe alloys
No full textThis thesis was scanned from the print manuscript for digital preservation and is copyright the author.
Researchers can access this thesis by asking their local university, institution or public library to
make a request on their behalf. Monash staff and postgraduate students can use the link in the References field
elliegiulietti/V-Cr-Ti-for-Fusion-Reactors: Vanadium_Alloys (V-Cr-Ti)_for_Fusion_Reactors_AM_Study_Release_v1.0
No full text<h2>Vanadium Alloys (V-Cr-Ti) for Fusion Reactors AM Study</h2>
<p>This repository contains the research and experimental data related to the study on vanadium alloys (specifically V-Cr-Ti alloys, V44 and V1515) for fusion reactors using additive manufacturing (AM) techniques.</p>
<h3>Overview</h3>
<p>Vanadium alloys are potential materials for nuclear fusion reactors due to their structural durability and irradiation resistance. This study focuses on investigating the viability of V-Cr-Ti alloys for AM procedures, aiming to understand crack behaviour and optimise laser parameters for better melt track formation.</p>
<h3>Key Findings</h3>
<ul>
<li>Experimental investigations involved varying laser power and speed on V-Cr-Ti alloys (V44 and V1515) to observe crack behaviour across melt tracks on a laser powder bed fusion (LPBF) machine.</li>
<li>Main types of cracks associated with AM melt tracks were identified, including liquation cracks (LC), solidification cracks (SC), and solid-state cracks (SSC).</li>
<li>Qualitative analysis involved visually determining crack types using optical microscopes and scanning electron microscopy (SEM), while quantitative analysis measured crack density using ImageJ software.</li>
<li>Results indicate that high laser power and low laser speeds result in increased cracking, while low laser power with a mid-range of laser speeds result in less cracking and a more optimal melt track.</li>
<li>An operating window between 60 and 150 W laser power and 850 to 1500 mm/s has been identified, with further studies required for confirmation and comparison to powder processing.</li>
</ul>
<h3>Future Directions</h3>
<ul>
<li>Future studies should focus on comparing data with similar alloys, refining laser parameters, and exploring microstructural properties for deeper insights into crack formation mechanisms.</li>
<li>Sharing of experimental data to facilitate accessibility and reusability for the scientific community.</li>
</ul>
<h3>Dissertation Details</h3>
<p>Dissertation submitted to the University of Sheffield in partial fulfilment of the requirements for the degree of Master of Engineering.
Dissertation title: Vanadium Alloys for Fusion Reactors: Determining their Viability for Additive Manufacturing Procedures.
Author: Ellie Giulietti
Supervisor: Dr Russell Goodall
May 2024</p>
Precipitation behaviour of Ti enriched phase in Ti bearing slag
No full textIn the present paper, a high titanium molten (high Ti) slag was employed as an additive to modify the titanium bearing blast furnace (Ti-BF) slag in order to investigate the influence of the addition of high Ti slag on the crystallisation behaviour of the Ti-BF slag. The variation in the Ti enriched phase and the precipitation behaviour of the Ti enriched phase in the Ti bearing slag were studied in this paper. The Ti bearing slag in this paper was composed of different proportions of high Ti slag and Ti-BF slag. A combination of X-ray powder diffraction, scanning electron microscope equipped with energy dispersive X-ray spectroscope and optical microscopy was applied to determine the crystal structure, clarify the chemical composition and observe the morphology of the Ti enriched phase. It was found that the Ti enriched phase transformed from CaTiO3 to Mg4Al2Ti9O25 with the addition of high Ti slag. When the Ti bearing slag contained 60 wt-% high Ti slags, Mg4Al2Ti9O25 became the only Ti enriched phase, and it could crystallise completely when the slag was held at 1450 degrees C for 25 min. The formation mechanism of Mg4Al2Ti9O25 is also discussed in this paper.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000306071700004&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Metallurgy & Metallurgical EngineeringSCI(E)EI8ARTICLE6414-4183
FTIR spectroscopy of Ti-chondrodite, Ti-clinohumite, and olivine in deeply subducted serpentinites and implications for the deep water cycle
No full textInternational audienceSeparated olivine grains from a deeply subducted serpentinized wehrlite (Changawuzi in the western Tianshan ultrahigh-pressure belt, China) were analysed with unpolarized transmission FTIR and the Ti contents were determined using LA-ICP-MS. The major bands in the olivine spectra display striking similarities to Ti-clinohumite and are interpreted as OH in lamellae. The quantification of the water content in lamellae requires calibration of the IR-absorption for such bands. We have obtained a new absorption coefficient for Ti-clinohumite of 0.125+/−0.017 ppm cm2 based on polarized FTIR measurements on three orthogonal sections through a large single crystal of Ti-clinohumite from Val Malenco, which has a known water content of 1.53 wt%. The resulting water content in olivine using this calibration factor ranges from 440 to 2,600 ppm and correlates positively with the Ti content that ranges from 130 to 1,400 ppm. For the quantification of the water content in Ti-chondrodite and Ti-clinohumite that are associated with olivine, we developed a new method using attenuated total reflectance FTIR spectroscopy. Ti-chondrodite and Ti-clinohumite display similar IR bands at ~3,562, 3,525 and ~3,583–3,586 cm−1. As in olivine, the water content and Ti content correlate in both Ti-clinohumite and Ti-chondrodite, indicating an intergrowth of these minerals, which has been confirmed by TEM analyses. Our results confirm previous suggestions that there is a strong correlation between the Ti content of ultramafic rocks and their capacity to transport water to the deeper mantle in subduction zones beyond conditions where hydrous phases are stable
On energy storage of Lu2O3:Tb,M (M=Hf, Ti, Nb) sintered ceramics: Glow curves, dose-response dependence, radiation hardness and self-dose effect
No full textThermoluminescent properties and energy storage characteristics of Lu2O3:Tb,M (M = Hf, Ti, Nb) sintered ceramics induced by ionizing radiation are presented and discussed. Dose-response dependence, radiation hardness and fading are studied. A linearity of the former exceeding seven orders of magnitude is confirmed for Lu2O3:Tb,Hf and Lu2O3:Tb,Nb ceramics. Lu2O3:Tb,Hf shows the best TL performance and also its fading is the lowest reaching 15% over 7 h and shows tendency to saturate. During the same period of time the Lu2O3:Tb,Ti, despite having TL at higher temperatures, losses about 25% of the stored energy and the TL signal of Lu2O3:Tb,Nb fades by almost 40% over 7 h. First order TL kinetics is confirmed for all three compositions. A self-dose effect in Lu2O3:Tb,Hf due to a natural content of the radioactive isotope (2.6%) is proved to be important for long-time reading of low doses.Accepted Author ManuscriptRST/Luminescence Material
UHP Metamorphism Documented in Ti-chondrodite- and Ti-clinohumite-bearing Serpentinized Ultramafic Rocks from Chinese Southwestern Tianshan
No full textThe southwestern Tianshan (China) metamorphic belt records high-pressure (HP) to ultrahigh-pressure (UHP) conditions corresponding to a cold oceanic subduction-zone setting. Serpentinites enclosing retrogressed eclogite and rodingite occur as lenses within metapelites in the UHP unit, which also hosts coesite-bearing eclogites. Based on the petrology and petrography of these serpentinites, five events are recognized: (1) formation of a wehrlite–harzburgite–dunite association in the mantle; (2) retrograde metamorphism and partial hydration during exhumation of the mantle rocks close to the seafloor; (3) oceanic metamorphism leading to the first serpentinization and rodingitization; (4) UHP metamorphism during subduction; (5) retrograde metamorphism during exhumation together with a second serpentinization. The peak metamorphic mineral assemblage of the serpentinized wehrlite comprises Ti-chondrodite + olivine + antigorite + chlorite + magnetite + brucite. A computed pseudosection for this serpentinized wehrlite shows that the Al content in antigorite is mostly sensititive to temperature but can also be used to constrain pressure. The average XAl = 0·204 ± 0·026 of antigorite (XAl = Al (a.p.f.u.)/8, where Al is in atoms per formula unit for a structural formula M48T34O85(OH)62, and M and T are octahedral and tetrahedral sites, respectively) included in Ti-chondrodite and average XAl = 0·203 ± 0·019 of antigorite in the matrix result in a well-constrained peak metamorphic temperature of 510–530°C. Peak pressures are less precisely constrained at 37 ± 7 kbar. The Tianshan serpentinites thus record UHP metamorphic conditions and represent the deepest subducted serpentinites discovered so far. The retrograde evolution occurs within the stability field of brucite + antigorite + olivine + chlorite and formation of Ti-clinohumite at the expense of Ti-chondrodite has been observed, suggesting isothermal decompression. The resulting P–T path is in excellent agreement with the metamorphic evolution of country rocks, indicating that the UHP unit in Tianshan was subducted and exhumed as a coherent block. To refine the metamorphic path of the ultramafic rocks, we have investigated the stability fields of Ti-chondrodite and Ti-clinohumite using piston-cylinder experiments. A total of 11 experiments were conducted at 25–55 kbar and 600–750°C in a F-free natural system. Combined with previous experiments and information from natural rocks we constructed a petrogenetic grid for the stability of Ti-chondrodite and Ti-clinohumite in F-free peridotite compositions. The formation of Ti-chondrodite in serpentinites requires a minimum pressure of about 26 kbar, whereas in Ti-rich systems it can form at considerably lower pressures. A key finding is that at UHP conditions, F-free Ti-chondrodite or Ti-clinohumite breaks down in the presence of orthopyroxene between 700 and 750°C, at temperatures that are significantly lower than those of the terminal breakdown reactions of these humite minerals. These breakdown reactions are an additional source of fluid during prograde subduction of serpentinites
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