Fine Deposits Research Articles

Time‐transgressive tunnel‐valley infill revealed by a three‐dimensional sedimentary model, Hamburg, north‐west Germany

AbstractDeep, elongated incisions, often referred to as tunnel valleys, are among the most characteristic landforms of formerly glaciated terrains. It is commonly thought that tunnel valleys were formed by meltwater flowing underneath large ice sheets. The sedimentary infill of these features is often highly intricate and therefore difficult to predict. This study intends to improve the comprehension of the sedimentology and to establish a conceptual model of tunnel‐valley infill, which can be used as a predictive tool. To this end, the densely sampled, Pleistocene tunnel valleys in Hamburg (north‐west Germany) were investigated using a dataset of 1057 deep wells containing lithological and geophysical data. The stratigraphic correlations and the resulting three‐dimensional lithological model were used to assess the spatial lithological distributions and sedimentary architecture. The sedimentary succession filling the Hamburg area tunnel valleys can be subdivided into three distinct units, which are distinguished by their inferred depositional proximity to the ice margin. The overall trend of the succession shows a progressive decrease in transport energy and glacial influence through time. The rate of glacial recession appears to have been an important control on the sedimentary architecture of the tunnel‐valley fill. During periods of stagnation, thick ice‐proximal deposits accumulated at the ice margin, while during rapid recession, only a thin veneer of such coarse‐grained sediments was deposited. Ice‐distal and non‐glaciogenic deposits (i.e. lacustrine, marine and terrestrial) fill the remaining part of the incision. The infill architecture suggests formation and subsequent infill of the tunnel valleys at the outer margin of the Elsterian ice sheet during its punctuated northwards recession. The proposed model shows how the history of ice‐sheet recession determines the position of coarse‐grained depocentres, while the post‐glacial history controls the deposition of fines through a progressive infill of remnant depressions.

Building an 18 000-year-long paleo-earthquake record from detailed deep-sea turbidite characterisation in Poverty Bay, New Zealand

Abstract. Two ~20 m-long sedimentary cores collected in two neighbouring mid-slope basins of the Paritu Turbidite System in Poverty Bay, east of New Zealand, show a high concentration of turbidites (5 to 6 turbidites per meter), interlaid with hemipelagites, tephras and a few debrites. Turbidites occur as both stacked and single, and exhibit a range of facies from muddy to sandy turbidites. The age of each turbidite is estimated using the statistical approach developed in the OxCal software from an exceptionally dense set of tephrochronology and radiocarbon ages (~1 age per meter). The age, together with the facies and the petrophysical properties of the sediment (density, magnetic susceptibility and P-wave velocity), allows the correlation of turbidites across the continental slope (1400–2300 m water depth). We identify 73 synchronous turbidites, named basin events, across the two cores between 819 ± 191 and 17 729 ± 701 yr BP. Compositional, foraminiferal and geochemical signatures of the turbidites are used to characterise the source area of the sediment, the origin of the turbidity currents, and their triggering mechanism. Sixty-seven basin events are interpreted as originated from slope failures on the upper continental slope in water depth ranging from 150 to 1200 m. Their earthquake trigger is inferred from the heavily gullied morphology of the source area and the water depth at which slope failures originated. We derive an earthquake mean return time of ~230 yr, with a 90% probability range from 10 to 570 yr. The earthquake chronology indicates cycles of progressive decrease of earthquake return times from ~400 yr to ~150 yr at 0–7 kyr, 8.2–13.5 kyr, 14.7–18 kyr. The two 1.2 kyr-long intervals in between (7–8.2 kyr and 13.5–14.7 kyr) correspond to basin-wide reorganisations with anomalous turbidite deposition (finer deposits and/or non deposition) reflecting the emplacement of two large mass transport deposits much more voluminous than the "classical" earthquake-triggered turbidites. Our results show that the progressive characterisation of a turbidite record from a single sedimentary system can provide a continuous paleo-earthquake history in regions of short historical record and incomplete onland paleo-earthquake evidences. The systematic description of each turbidite enables us to infer the triggering mechanism.

Formation of Fine Iron Ore Tailings Deposits

Deposit formation back analysis of a two-year iron ore slime impoundment managed by the sub-aerial method is performed using two complementary approaches. The first one tries to identify the deposit stratigraphy and its formation history. This is made possible through sorted document review (reports, design documents, personal communication, photos, etc.) and by means of an extensive geotechnical investigation program, including laboratory and field testing. The second approach, considered more quantitative, deals with modeling the sub-aerial deposition method, using a numerical solution for events such as large strain consolidation and desiccation of fine, soft tailings, following filling and waiting periods, according to that disposal technique. For modeling, the computer program CONDES is used with constitutive functions of available material, also using actual slime management data. The numerical model rendered a final deposit height of 8.16 m, very close to the actual height measured in the field, providing the model validation. The analyses suggest that the desiccation process inherent to the sub-aerial method had a minimal effect or did not even occur during the impoundment operation. Other potential disposal schemes were also evaluated and comparisons were made. The study has shown the ability to understand the formation of fine iron ore mining tailing deposits, and how to make use of this tool in projects.

Fine Particle Dispersion and Deposition in Three Different Square Pore Flow Structures

This paper investigates numerically the motion and deposition behaviors of micro- or nano-scaled particles in fluid passing three different kinds of square pores. The three kinds of square pores represent different pore structures in porous medium. The flow fields are numerically simulated by lattice Boltzmann method (LBM). The computation procedure code was validated by comparing the results with those of the previous works for the case of particle fluid passing a square block in a two dimensional channel flow. The results show that the dispersion of particles in three different square pore structures are much different, and vary with Stokes numbers for the same square pore even the Reynolds numbers are the same. In addition, the number and the position of deposited particles are analyzed. It shows that the deposition characteristics of each wall are mainly influenced by Stokes number, Reynolds number and the pore structure.

Filtration and Catalytic Reaction in Trickle Beds: The Use of Solid Foam Guard Beds To Mitigate Fines Plugging

The sensitivity of catalytic reactions to concurrent filtration and fines deposition in trickle-bed reactors (TBRs) was assessed by means of the catalytic hydrogenation of α-methylstyrene from kaolin–kerosene suspension flows. A negative correlation between catalytic conversion and the specific deposit of the bed resulted from the extra mass-transfer step that built up on the collectors in the course of filtration. The severity of the evolving extra mass-transfer step was sensitive to deposit compaction resulting from higher gas superficial velocities. Furthermore, irreversible catalyst activity losses were observed after catalyst cleanup and were ascribed to irretrievable active sites by catalyst intraparticle fines trapping. Fines accumulation in the catalyst bed was notably reduced by means of high-porosity solid-foam modules used as guard filters and placed upstream of, and adjacent to, the trickle bed. Hydrodynamic studies were carried out with alumina and silicon carbide solid foams to assess their role on the distribution of suspension and the reduction of specific deposit and pressure drop in trickle beds. It was found that the foam capture efficiency critically depended on the open connectivity of foam cells and the physicochemical nature of foam materials. The numbering up of foam modules led to reduced overall specific deposits of the beds and pressure drops, foreseeing a prospect for prolonging the hydrotreatment TBR lifetime, using solid foam as guard beds.

Corneal endothelial decompensation: a novel ocular manifestation of multiple sclerosis

Abstract Purpose To report the in vivo and ex vivo histopathologic features of the cornea in a patient with endothelial decompensation within the scope of multiple sclerosis (MS). Methods During a 2‐year period a 64‐year‐old male patient, suffering from multiple sclerosis and unilateral bullous keratopathy, was repeatedly examined by slit‐lamp and in vivo confocal microscopy (IVCM). Light microscopy with histochemical staining, transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were performed on the corneal button obtained at penetrating keratoplasty. Results Besides corneal decompensation on his left eye, slit‐lamp examination of both eyes showed a deposition of translucent vesicles on the iris and fine deposits on the corneal endothelium and anterior lens pole. Observation of the endothelium by IVCM confirmed fine precipitates in the right eye, and displayed larger deposits in the left eye. After further deterioration, the left eye showed endothelial denudation. Light microscopy of the corneal button showed periodic acid‐Shiff and Giemsa positive granular deposits in the epithelium and stroma. The same electron dense deposits displayed a fingerprint configuration with TEM. This finding corresponds with a deposition of neurodegenerative origin. SEM disclosed similar unique morphological changes of the endothelial cells as detected by IVCM. Lichen‐like deposits were observed on the endothelial cells. Conclusion IVCM enabled us to obtain high resolution images of the endothelial layer in an obscured cornea. This resulted in the discovery of a new ocular manifestation of multiple sclerosis.

Effect of channel size and flow modulation on filtration in monolith reactors with cocurrent gas-suspension downflow

Filtration and catalytic reaction studies of gas/(kaolin-kerosene) suspension flows through monolith reactors were conducted in isoflow-rate and in flow modulation modes in cocurrent downflow. Monoliths with small (1-mm) and large (4-mm) square channel openings were investigated. The effect of deposition of fines on the catalytic conversion in monolith reactors was assessed using the catalytic hydrogenation of α-methylstyrene as a model reaction on 1%Pd–alumina washcoated monolith blocks. The catalytic tests revealed that conversion was a decreasing function of monolith bed specific deposit. To reduce the impact of deposition on catalytic conversion, three feed flow rate modulation strategies (ON–OFF liquid-, ON–OFF gas- and gas/liquid alternating modes) for on-line self-cleaning of deposits were tested. The dynamics of liquid pulsations generated via these cyclic operation strategies was monitored using electrical capacitance tomography imaging. The corresponding liquid saturation, pressure drop and pulsation intensity were compared for clean fines-free two-phase flows. Under isoflow filtration, monoliths with large opening channels were found to favor detachment of kaolin deposit layers and to promote sieving filtration. Instabilities induced by the three flow modulation strategies favored detachment and removal of the deposits only for the large-opening channel monoliths. Conversely, detachment followed by re-deposition downstream in the bed in small-channel opening monoliths aggravated the deposition and pressure buildup in flow modulation. Hence, small-opening channels can be recommended for isoflow filtration of suspensions whereas large-diameter channels are preferable for cyclic operations.

The Kano–Kazaure highway, north central Nigeria: the significance of the engineering geology in construction

Kano–Kazaure highway traverses granitic rock with minor occurrences of metasediments and fine sandy deposits. The soil profiles were studied to determine their suitability in the proposed dualization of the highway route as part of the Trans-Sahara international highway construction project. The soils derived from the granitic rocks are well graded, with a high maximum dry density and low optimum moisture content. The soils derived from the schistose and quartzite zone are also suitable for road base and sub-base but the transported loose silty fine sand/sandy silty soils of the Chad Formation are only limited suitability.

相対的海水準の急激な上昇イベントが示唆する養老断層系の完新世活動―濃尾平野西縁におけるボーリングコアの解析から―

A 6000-year history of relative sea-level change on the western Nobi plain, at the footwall side of the Yoro fault, was reconstructed from three drilling cores based on analyses of sedimentary facies, grain-size distributions and electrical conductivity (EC), as well as 20 14C age determination. The Yoro fault comprises the northern part of the Yoro fault system. These cores show a prograding delta sequence. Two intervals characterized by fine deposits, mainly composed of fine sand, and high EC value are identified in sandy delta front deposits showing a general coarsening upward sequence. In synchronous with these changes in the delta front, a rapid rise of EC value is recognized in the abandoned channel fill deposits on the delta plain. These data suggest that temporal sea-level rise events occurred during the progradation process of the delta system. A probable cause of these events is coseismic subsidence. These subsidence events are dated at around 5600-4700 cal BP and 4600-3800 cal BP, respectively. The above-mentioned subsidence events broadly correspond with previously known faulting events at the Kuwana fault to the south of the Yoro fault. Evidence for the faulting of the Yoro and Kuwana faults associated with two historical earthquakes (AD 745 and AD 1586) accompanied by coseismic subsidence and synchronicity of the subsidence events identified in this study and faulting events at the Kuwana faults suggest that subsidence events identified in this study are caused by faulting at the Yoro fault. These results are consistent with the notion that the Yoro and Kuwana faults comprise a behavioral segment in the Yoro fault system.

562 レーザ・アシスト超微粒子エアロゾルデポジション法に関する研究 : 超微粒子流-レーザ光同軸ノズルを用いた微小タワー成形(GS 機械材料・材料加工・潤滑)

562 レーザ・アシスト超微粒子エアロゾルデポジション法に関する研究 : 超微粒子流-レーザ光同軸ノズルを用いた微小タワー成形(GS 機械材料・材料加工・潤滑)

Morava River floodplain development during the last millennium, Strážnické Pomoraví, Czech Republic

Floodplain sediments deposited along the lower course of the Morava River (eastern Czech Republic), were studied in the Strážnické Pomoraví region to describe the alluvial history of the river over the last millennium. The sediments exposed in up to 5 m high erosional river banks were analysed using mineral magnetic, geochemical and chemical approaches. The age model of the sedimentary sequences was constructed from radiocarbon dates in association with 206Pb/207Pb and POP (DDT, PCB) analysis and 137Cs activity data. The Cu-trien method was used for stratigraphically correlating these deposits based on the variation of expandable clay minerals in the sediments. The resulting stratigraphic pattern reveals the alluvial history of the currently active river channel system since the end of the first millennium AD. Fine overbank clayey sediments deposited during the `Mediaeval Warm Period' were eroded from cultivated fields newly formed during Mediaeval colonization between 1250 and 1450. These fine deposits are overlain by coarser floodplain sediments of the `Little Ice Age', indicating a change in the sediment source since the sixteenth century AD, and a substantial increase in the sediment load in the second half of twentieth century. The Strážnické Pomoraví floodplain deposits represent a valuable palaeoenvironmental archive of the last millennium, containing records of fluvial processes considerably altered by human activities.

Reactivity of α,ω-dibromoalkanes at copper and silver cathodes: (I) Behaviour of 1,3-dibromopropane

Evidence is presented that copper, silver, and their alloys with palladium, may display an exceptional reactivity in the contact of α,ω-alkanes [Br–(CH 2) n –Br]. Thus, the use of coppered surfaces as cathode materials shows a spectacular potential shift ( ΔE ≈ 1 V) for the main reduction step when compared to glassy carbon taken as a standard interface. Such cathodic reactions are particularly easy and fast with 1,3-dibromopropane ( DB3). Thus, it is expected that a preliminarily transient [(CH 2) 3Cu (II),2Br −] monomer or polymer, is formed: the indirect reduction by use of 3D electrodes from copper powder in suspension may produce at electrified surfaces (made of glassy carbon, platinum, or nickel) fine deposits of copper nano-particles. Oppositely, silver (essentially by means of Ag–Pd alloy employed as cathode material) reacts with each C–Br bond and the observed cathodic behaviour is uniform with all α,ω-alkanes. A special attention is drawn on the nature of modified surfaces and the enhancement of catalysis kinetics brought by the use of copperized and silverized electrodes.

Responses of Aquatic Macroinvertebrates to Stream Channel Reconstruction in a Degraded Rangeland Creek in the Sierra Nevada

Streams on western rangelands are sometimes degraded to the point that reestablishing lost ecological values requires rebuilding their physical structure, shape, and form. We evaluated the biological response to reconstruction of a small rangeland stream channel through comparisons of aquatic invertebrate communities before and after engineering activities and in relation to local and regional reference stream conditions. We measured geomorphic and riparian habitat features along with benthic macroinvertebrates for two years prior to restoration actions and for two years afterward. Stream restoration activities included the construction of a new channel to replace an incised meadow stream reach (including addition of coarse rock substrate, erosion control fabric, and willow planting) and the rehabilitation of gullies and roads in the meadow and its watershed. In postproject monitoring, we found statistically significant changes in the macroinvertebrate community and trophic structure at the restored site. These were exhibited as increases in EPT taxa (mayflies, stoneflies, caddisflies) and the proportion and diversity of sensitive taxa, decreased tolerant taxa, and an increase in consumers of riparian organic matter (shredders) and decrease in fine organic particle filter-feeders. A site monitored downstream of the restoration activities exhibited increased deposition of fines and sand one year after project construction, but was similar to preproject conditions in the second year, and the macroinvertebrate community was unchanged. Improved biological integrity at the restored site showed that rapid recovery can occur in rebuilt streams within rehabilitated watersheds, but neither degraded nor enhanced conditions were transferred to downstream habitat, at least over the initial postproject period.

Solidification mechanism of allophane by hydrothermal reaction

Solidified materials were prepared by subjecting powder compacts consisting of allophane and slaked lime to hydrothermal reaction at various temperatures. Hydrogarnet was formed after the hydrothermal reaction because of the reaction between allophane and slaked lime. The bending strength of the materials solidified by hydrothermal reaction at 80 °C was greater than 6 MPa. The improvement in the strength of materials by hydrothermal reaction at 80 °C was due to the formation of fine deposits at the surface of allophane aggregates; these deposits filled the spaces between particles of the starting materials. Hydrothermal reaction at temperatures greater than 120 °C resulted in the collapse of the allophane structure, leading to a decrease in the strength of the materials.

Post Service Examination of a Tritium Permeator and a Turbomolecular Pump from the CAPER Facility at the Tritium Laboratory Karlsruhe

After 8 years of operation at the CAPER facility at the Tritium Laboratory Karlsruhe, a permeator used to separate hydrogen species from processed gases ceased operation due to multiple heater failures. This was subjected to post service examination to find the cause of the failures. This paper describe the methods used to locate the failures in the heaters and the likely cause. It was also necessary to determine the tritium inventory embedded in the structure for safe disposal. Destructive examination, adapted from a full combustion technique, was used on sections of the permeator. A fine black powder deposit, presumed to be mostly carbon, coated the surfaces of the inlet section of the feed side. This powder contained nearly half of the tritium within the permeator. The likely source of the powder and the consequences for the operation and eventual decommissioning of the ITER Tritium Plant are discussed. A failed turbomolecular pump from CAPER was also examined. There was evidence of wear on the emergency support bearing, but more importantly, when the pump internals were exposed to the glove box atmosphere (dry air) large quantities of tritium were rapidly released, this despite the isotopic swamping before removal from the CAPER glove box. Significant uptake of tritium in electrical insulation was also found.

The effect of nonylphenylpolyethylene glycol on the kinetics and morphology of silver cemented using zinc, iron, copper and aluminum

The effect of nonylphenylpolyethylene glycol (D1) and cementing agents zinc, iron, copper and aluminum on silver cementation kinetics and deposit morphology was investigated. It was found that D1 inhibits both silver cementation and cementing agent dissolution with greater effect on cementing agent dissolution. The silver deposition rate and metal consumption per mole silver decreased in the order Zn, Fe, Cu, Al. The addition of D1 resulted in the rate of cementation decreasing to 77–90% of that when D1 was absent. The slower deposition resulted in more efficient consumption of cementing agent with 15–34% less dissolved when D1 was present. The deposit morphology strongly depends on the cementing agent: a coarse layer with high porosity was obtained on zinc, a fish-gill deposit morphology on iron, a compact fine deposit on copper and a patchy dendritic deposit on aluminum. D1 strikingly decreased the porosity of the deposits on zinc and iron.

Dynamics of fines deposition in an alternating semifluidized bed

A semifluidized bed was proposed to allay bed plugging during the filtration of fines-hydrocarbon suspensions. Mitigation of plugging was allowed by alternating semifluidization during capture with unconstrained fluidization for removal of deposits. Solids holdup conditions were established to prevent deposition in the fluidization section. The cyclic parameters were varied to allow efficient removal of deposits during washing. Analysis with a filtration model accounting for solids detachment in the fixed bed section revealed that the fluidization section favored growth of aggregate size entering the fixed bed. Analysis of the split ratios between fixed and fluidized bed heights revealed that the shallowest fluidization sections delayed deposition in the fixed bed. In cyclic operation, reversibility of the semifluidized bed was best recovered via gas injection during the washing stages. However, the filtration times in successive cycles shortened with increasing washing times but lengthened with increasing the washing superficial suspension velocity. © 2008 American Institute of Chemical Engineers AIChE J, 2008

Amiodarone-Induced Keratopathy: Full-Thickness Corneal Involvement

To report a case of amiodarone-induced keratopathy involving the entire cornea, including the endothelium. Clinical case description and documentation with confocal laser scanning microscopy using the Heidelberg Retinal Tomography II (HRT II). A 65 year-old man with a history of blurred vision and seeing halos around lights had been treated with amiodarone for 6 years. Best-corrected visual acuity was 20/25 in each eye. Slitlamp examination of both eyes showed a bilateral, symmetric, whorllike pattern of brown deposits in the inferocentral corneal epithelium. Diffuse and fine deposits resembling keratic precipitates in the central part of the endothelial face were also detected. Examination of the lens, optic nerve, and fundus in each eye did not show any abnormalities that could be attributed to the amiodarone therapy. Severe endothelial deposition was documented with the confocal laser scanning microscope of the HRT II. Amiodarone-induced keratopathy with confluent and diffuse endothelial deposition is rare, and it may be indicative of a more severe toxicity associated with amiodarone.

Long-term changes of intertidal and subtidal sediment compositions in a tidal basin in the northern Wadden Sea (SE North Sea)

Wadden Sea tidal flats are highly dynamic regarding the spatial distribution and the grain size composition of their sediments. From 2003 to 2006 surface sediments have been surveyed in an intertidal and a subtidal area within the tidal inlet Königshafen (south-eastern North Sea, northern Wadden Sea, island of Sylt) with the goal to gain information on short-term development trends in the grain size composition. The average grain size (Mean) becomes finer in the sheltered part of the intertidal survey area whereas a coarsening tendency can be observed in the more exposed part of the intertidal and especially in the subtidal survey area. The trend of the most frequent grain size (first Mode) shows the same spatial distribution pattern but is far less distinct. Thus, the changing Mean must be related to an increase in the deposition of fines in the sheltered part of the intertidal Königshafen as well as a general removal of fine-grained material in the exposed intertidal and subtidal Königshafen. In order to see long-term trends the surveys of 2003–2006 were compared to earlier studies conducted in 1932/1933, 1981 and 1989. A significant depletion of mud can be observed in the entire survey area. It is concluded that primarily changed hydrodynamics that may accompany ongoing climate change are responsible for this. However, the loss of fine-grained sediments is additionally amplified by a reduced vegetation cover and coastal protection measures.

Sol‐Gel Inks for Direct‐Write Assembly of Functional Oxides

The ability to pattern oxide structures at the microscale in both planar and three-dimensional forms is important for a broad range of emerging applications, including sensors, micro-fuel cells and batteries, photocatalysts, solar arrays, and photonic bandgap (PBG) materials. Here, we report the fabrication of micro-periodic oxide structures by direct-write assembly of sol-gel inks. Specifically, we create both planar and three-dimensional (3D) architectures composed of submicron features, which are converted to the desired oxide phase upon calcination. Atomic force microscopy (AFM) and optical reflectivity measurements acquired on these micro-periodic structures reveal their high degree of structural uniformity. Several techniques have recently been introduced for patterning materials, including colloidal self-assembly, holographic lithography, and direct laser and ink writing approaches. Unfortunately, these approaches, apart from two notable exceptions, are confined to polymeric systems that lack the specific functionality required for a given application. As a consequence, the as-patterned structures require additional processing step(s) to produce the desired functional replicas. For example, 3D micro-fuel cells and photonic bandgap materials with inverse face centered cubic (fcc) structures have been templated from colloidal crystals, while silicon photonic crystals in both normal and inverse woodpile architectures have been templated from polymer structures produced by direct laser and ink writing, respectively. To circumvent the need for complicated templating schemes, we are developing a family of sol-gel inks that enable the direct ink writing (DIW) of functional oxides at the microscale. DIW is a layer-by-layer assembly technique, in which materials are fabricated in arbitrary planar and 3D forms with lateral dimensions that are two orders of magnitude lower than those achieved by ink-jet printing. Paramount to our approach is the creation of concentrated inks that can be extruded through fine deposition nozzles as filament(s), which then undergo rapid solidification to maintain their shape even as they span gaps in underlying layer(s). Unlike our prior efforts based on polyelectrolyte inks that require a reservoir-induced coagulation to enable 3D printing, these new inks can be directly printed in air providing exquisite control over the deposition process (e.g., the ink flow can now be started/stopped repeatedly during assembly). We first demonstrate this new ink design by creating a solgel precursor solution based on a chelated titanium alkoxide, titanium diisopropoxide bisacetylacetonate (TIA). TIA has an octahedral coordination of two isopropoxide and two acetylacetone (acac) groups about a central titanium (Ti) atom (Fig. 1a). This molecular structure is ideal, as it leads to the formation of soluble linear chains upon hydrolysis and condensation of the labile isopropoxide groups in the presence of a base catalyst. Subsequent slow hydrolysis of the acac groups leads to further gelation, which when coupled with solvent evaporation, results in the formation of a concentrated ink (Fig. 1b). An organic polymer, polyvinyl-pyrrolidone (PVP), is also incorporated to mitigate stresses that occur during drying and calcination of the as-patterned structures. We tailor the ink viscosity for DIW through micron-sized nozzles by regulating the solids content, defined as Ti + PVP concentration (wt %). The initial precursor solution contains 6.6 wt % solids and possesses a low viscosity ∼ 0.01 Pa·s, as shown in Figure 1c. However, upon concentrating the ink via solvent evaporation, a dramatic rise in viscosity is observed. For example, a nearly four-fold increase in ink concentration leads to a three orders of magnitude rise in its viscosity. Using an approximation of the Hagen–Poiseuille model, we estimate that the optimal ink viscosity ranges from 2.1– 4.2 Pa·s for the DIW conditions employed in this study (i.e., 1 lm deposition nozzle, 400 lm s deposition speed, and an applied pressure of 275–550 kPa). There is good agreement between the predicted values and those deemed optimal experimentally for microscale printing, as highlighted by the shaded region in Figure 1c. These inks not only flow readily, but are concentrated enough to rapidly solidify and maintain their cylindrical shape upon exiting the nozzle. The ink solidification mechanism can be understood by examining its elastic (G′) and viscous (G′′) moduli in the presence and absence of an ethanol solvent trap (Fig. 1d). The asprinted ink exhibits a liquid-like response (i.e., G′′> G′). HowC O M M U N IC A IO N