Narrow Grain Size Distribution Research Articles

A Site-specific Comparison of Permeability Prediction Models in Alluvial Sediments from Physical and Geoelectrical Measurements

An evaluation of five petrophysical models for hydraulic permeability predication was completed for a site-specific set of alluvial sediments. The models considered were the Kozeny-Carmen (1927–1937), Börner (1996), Revil-Cathles (1999), and two Revil-Florsch (2010) models. The river deposited sediments represent a relatively narrow grain-size distribution, and were acquired adjacent to the Kansas River, in Olathe, Kansas. Using measured physical, electrical, and hydraulic data from Slater and Glaser (2003) , a comparison of the performance of these five petrophysical models for hydraulic permeability estimation of soils was completed. For models where the key parameter is effective grain-size, three model variations were considered using d10, d50, and d90, resulting in an evaluation of a total of eleven individual models. Parameters included in the models can be classified as three different types: a) physical parameters only, b) electrical parameters only, and c) physical and electrical parameters together. The performance of each model was rated in terms of linear regression R squared, slope, and y-intercept values when plotted against the measured hydraulic conductivities. The top three models were the Kozeny-Carmen, a modified Revil-Cathles, and the Börner model. The Kozeny-Carmen model performed with the highest rating, followed by the modified Revil-Cathles model, and the Börner model rounding out the top three. There was a significant disparity between the rating associated with the top three and the fourth best performing model suggested by Revil and Florsch. However, it should be noted that the Börner model and Revil-Florsch model are based entirely on electrical measurements. The Revil-Cathles model was greatly improved when d10 was substituted for d50 for this limited sediment grain-size range.

Tensile properties of three-dimensionally interconnected graphene-networked Cu composite and changes in its microstructure in relation to heat treatment temperature

An investigation of microstructure changes in a new, in situ-fabricated, three-dimensionally interconnected graphene-networked Cu composite was performed in relation to the heat treatment temperature in H2 and in air. Heat-treated in H2 revealed that recrystallization commenced at ~ 300 ℃ and the crystal grew afterward. However, the crystal growth was constrained within the initial Cu grains and inhibited due to Cu grains being wrapped by the stable graphene, even at 1000 ℃. This resulted in similar or narrower grain-size distribution. Meanwhile heat treatment in air resulted in the oxidation of carbon, instability of graphene, and crystal growth over the grain boundaries, which resulted in a wider grain-size distribution. Increases in tensile and plastic deformation (30% and 144%, respectively) were observed due to the grain size refinement and the strong interfacial bonds between graphene and the Cu matrix. The result was greater load bearing and toleration of a substantial load during plastic deformation.

The effect of Ni/Fe ratio on the physical properties of NiFe2O4 nanocomposites

Spinel ferrites nanoparticles were prepared using hydrothermal technique. The atomic ratio of Ni to Fe in the solution is ranged from 0 to 75% in order to investigate its effect on the structural, morphological and magnetic properties of the prepared spinel phases. The powder crystallographic structure was studied by means of x-ray diffraction (XRD). The morphology was studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) observations. Vibrating sample magnetometer (VSM) was used to characterize the magnetic properties of powders. The XRD analysis reveals that the powders prepared with ratios Ni/Fe of 25 and 50% are pure nickel ferrite phase. However, at 75% ratio the powder is a mixture of hematite and mainly nickel hydroxide. The obtained nickel ferrites show narrow distribution of grain size which is reduced with increasing the Ni/Fe ratio; this variation is explained in terms of nucleation and grain growth. Nickel ferrite nanopowders exhibit a superparamagnetic behavior, due to their small size, and high magnetization saturation of 29.88 emu g−1. Thereafter, the prepared powders may found biomedical applications such as drug delivery.

Effect of the CoFe2O4 initial particle size when sintered by microwave on the microstructural, dielectric, and magnetic properties

AbstractThe particle size of CoFe2O4 powders (average particle size of 350 nm) was reduced to 50 nm by high‐energy milling. In this paper, special attention was given for analyzing the densification and grain growth of both particle sizes (350 and 50 nm) subject to ultrafast sintering assays using microwave sintering and their effect on the magnetic and electric properties. The results indicated that the grain growth was 10 times higher for the nanoparticle system, reaching similar sizes of ~1 μm in both cases after sintering. The relative density values were higher (95%) in the nanoparticle system due to the wide distribution of particle sizes generated in the grinding process. Qualitatively inferred microscopy analysis showed high sinterability of fine particles with a narrow distribution of grain size when subjected to ultrafast firing processes. Magnetization measurements at room temperature clearly show the reduction of Hc with increasing grain size. Electric resistivity, dielectric constant (ε′), and dielectric loss tangent (tan δ) were measured as a function of frequency at room temperature. The low values of dielectric constant (ε′) and dielectric loss (tan δ) in the low frequency range, shown for all samples sintered by microwave, prove the excellent uniformity in the microstructure.

Structural and electron spin resonance spectroscopic studies of MnxZn1−xFe2O4 (x = 0.5, 0.6, 0.7) nanoferrites synthesized by sol-gel auto combustion method

Nanoferrites with the chemical equation MnxZn1−xFe2O4 (x = 0.5, 0.6, 0.7) were prepared by sol-gel auto combustion method in order to study their structural, elastic and electron magnetic resonance properties. The Bragg reflections in the X-ray diffractograms matched with the formation of cubic spinel phase along with the secondary phases of α-Fe2O3 and Mn2O3. The uneven variation of lattice parameter was found to be depending on the possible cation redistribution in the spinel structure/or grain sizes. From the histograms of SEM studies, the composition x = 0.6 comparatively has a narrow distribution of grain sizes (5–11 μm) than those of compositions x = 0.5 (3.5–8.5 μm) and x = 0.7 (2.5–8.5 μm). The higher and lower vibrational frequencies in the FTIR spectra occurred around 560 cm−1 and 470 cm−1 confirm the cubic spinel phase of present ferrite systems in the line of XRD confirmation. The change in the vibrational frequencies supports the variation of lattice parameter. The variation of lattice energy is supportive for the elastic properties, but not to the structural parameters. The same value of Poisson’s ratio (∼0.35) for the three compositions is an indicative, representing the isotropic behaviour of spinel ferrite systems. The range (2.012–2.106) of Lande’s g-parameter indicates the change in Fe3+–O–Fe3+ superexchange interaction. The results are interpreted based on the possible cation redistribution, the secondary phases presuming the core-shell interactions.

Muddy sand and sandy mud on the distal Mississippi fan: Implications for lobe depositional processes

We used laser particle size analysis (LPSA) to quantitatively analyze grain-size characteristics from distal Mississippi submarine fan deposits (Gulf of Mexico) and relate them to established depositional models along the spectrum of sediment gravity flows. One hundred and seventy-nine (179) sediment samples from 22 beds were obtained from cores of Deep Sea Drilling Project Leg 96 Sites 614, 615, and 621. The sediment from Sites 614 and 615 was deposited in lobes ∼500 km downstream from the Mississippi canyon head. Most samples were described as sand from visual inspection of cores, containing >75% volume of sand grains, with clay content <5% based on LPSA. A muddy sand definition was given to sands comprising >20% silt and finer grains, with generally higher clay content (3%–16%). However, LPSA data show that facies assignments from visual core description overestimated the proportion of sand grains: 15% of samples initially interpreted as sand contain <75% sand grains; 40% of muddy sand samples have <50% sand. Samples from lobes at Sites 614 and 615 were compared to samples from Site 621, where beds are sandier with a relatively narrow distribution of grain sizes deposited in a more proximal channel setting, <250 km from the canyon head. We interpret the large proportion of silt and finer grains in the distal lobes to reflect diminished turbulence within sediment gravity flows as they expand from confined to unconfined settings downstream of channel conduits. Entrainment of finer-grained sediment at the channel-to-lobe transition could have also contributed to larger proportions of silt and finer grains in distal lobes.

Microstructure and mechanical behavior of an AISI 304 austenitic stainless steel prepared by cold- or cryogenic-rolling and annealing

An AISI 304 austenitic stainless steel (ASS) with various ultrafine- or fine-grained structures was fabricated by cold- or cryogenic-rolling and annealing. The microstructure and mechanical properties of the ultrafine- or fine-grained ASS were investigated based on statistical data and physical metallurgy. The results showed that much more volume fraction of α′-martensite can be obtained by cryogenic-rolling in comparison with cold-rolling under a similar rolling strain, and ε-martensite was a medium to transform into α′-martensite finally during cryogenic-rolling. The deformed ASS with larger volume fraction of α′-martensite was beneficial to obtaining finer structure with a narrow distribution of grain sizes after the similar annealing process. The cycle annealing was a feasible method to make reverse transformation completely and to inhibit the structural coarsening simultaneously for the cold- or cryogenic-rolling ASS. The yield strength was enhanced by cryogenic-rolling and cycle annealing to be approximately 2.7 times higher than that of solution-treatment state. The tensile strength was not changed evidently, and the uniform strain was apparently decreased with reducing grain size. There is no significant relevance between the mechanical stability of austenite and average grain size for the ultrafine- or fine-grained ASS; however, their mechanical stability was less than that of solution-treatment state.

Synthesis of MFe2O4 (M=Mg2+, Zn2+, Mn2+) spinel ferrites and their structural, elastic and electron magnetic resonance properties

Structural, elastic and electron magnetic resonance investigations of spinel ferrites with the formula MFe2O4 (M = Mg2+, Zn2+, Mn2+) synthesized by the sol-gel auto-combustion method are reported here. XRD patterns revealed the co-existence of secondary phases along with the ferrite phase. The lattice parameter (8.301 Å, 8.366 Å and 8.434 Å) was found to be varying according to the ionic radii of cations. As determined by scanning electron microscopy (SEM), ZnFe2O4 has a comparatively narrow distribution of grain sizes (1.3–3.8 µm) compared to those in MnFe2O4 (0.8–4.3 µm) and MgFe2O4 (0.3–4.8 µm). The estimated values of average crystallite sizes (17.5 nm, 21.3 nm and 23.3 nm) determined from the X-ray diffraction peaks are considerably less than the average grain sizes (1.3 µm, 1.6 µm and 2.7 µm) estimated from the SEM histograms. The vibrational frequencies in FTIR spectra are in the conformity with the cubic spinel structure and their variation supports the variation of lattice parameter. Equal values of Poission's ratio (0.35) were obtained for the three systems which represent the isotropic behaviour of spinel ferrite systems. The exceptional low value of Lande's g-parameter for ZnFe2O4 indicates the dominance of Fe3+–O–Fe3+ superexchange interaction. Though cation redistribution is possible in the present ferrite systems, the secondary phases existed in these ferrite systems are predominantly influencing the structural, elastic and electron magnetic resonance properties.

Facile Preparation of Core-Shell Magnetic Metal-Organic Framework Nanoparticles for the Selective Capture of Phosphopeptides.

In regard to the phosphoproteome, highly specific and efficient capture of heteroideous kinds of phosphopeptides from intricate biological sample attaches great significance to comprehensive and in-depth phosphorylated proteomics research. However, until now, it has been a challenge. In this study, a new-fashioned porous immobilized metal ion affinity chromatography (IMAC) material was designed and fabricated to promote the selectivity and detection limit for phosphopeptides by covering a metal-organic frameworks (MOFs) shell onto Fe3O4 nanoparticles, taking advantage of layer-by-layer method (the synthesized nanoparticle denoted as Fe3O4@MIL-100 (Fe)). The thick layer renders the nanoparticles with perfect hydrophilic character, super large surface area, large immobilization of the Fe(3+) ions and the special porous structure. Specifically, the as-synthesized MOF-decorated magnetic nanoparticles own an ultra large surface area which is up to 168.66 m(2) g(-1) as well as two appropriate pore sizes of 1.93 and 3.91 nm with a narrow grain-size distribution and rapid separation under the magnetic circumstance. The unique features vested the synthesized nanoparticles an excellent ability for phosphopeptides enrichment with high selectivity for β-casein (molar ratio of β-casein/BSA, 1:500), large enrichment capacity (60 mg g(-1)), low detection limit (0.5 fmol), excellent phosphopeptides recovery (above 84.47%), fine size-exclusion of high molecular weight proteins, good reusability, and desirable batch-to-batch repeatability. Furthermore, encouraged by the experimental results, we successfully performed the as-prepared porous IMAC nanoparticle in the specific capture of phosphopeptides from the human serum (both the healthy and unhealthy) and nonfat milk, which proves itself to be a good candidate for the enrichment and detection of the low-abundant phosphopeptides from complicated biological samples.

Nanostructured Zinc Electrodeposited from Protic Ionic Liquids: Comparison with Zinc Aqueous Electrodeposition Processes

Zinc electrodepositon is one of the more important electrochemical process for surface treatment because of its application in anticorrosion protection and also as electrode material in zinc batteries. The main limitation of the electrodepositon of zinc from acidic or basic solutions in aqueous media, in addition to the very negative potential needed to carry out the electrodeposition, is associated to the simultaneous hydrogen evolucion reaction (HER) limiting the farad¡c efficiency of the electrochemical process. The HER has also a direct effect on the nucleation and on the electrocrystallization of zinc with some negative effects on the physical and structural proporties of zinc electrodeposits obtained from these solution (e.g. (poor adhesion, inhomogeneous deposits, etc). In this work the electrodeposition processes of zinc from protic ionic liquids is studied and compared with results of electrodeposition from aqueous solution in order to determine the avantages of electrodeposition from ionic liquids. Results show that in protic carboxylated ionic liquids, as ethanolammonium propionate, homogeneous electrodeposits of pure metallic zinc are obtained, with a narrow distribution of grain size in the range of 50-70nm, contrariously to electrodeposits obtained from aqueos solutions with grain sizes from 20 to 100nm. In addition, differences in the nucleation-electrocrystallization mechanism and on the electrodeposition rate are observed and they are dependent on the nature of the nature of the solvent. Results allow to conclude that zinc electrodeposits continous, homogeneous and with a well controlled grain sizes can be obtained from protic ionic liquids. These results allow to envisage that these deposits can be more effective for anticorrosion protection since this property is dependent on the homogeneity and contoinuity of an electrodeposit. ACKNOWLEDGEMENTS. The financial support provided by CONACYT (México), project Fondo Sectorial SEP-CONACYT CB 2011 168032 and The Engineering Research Council of Canada (NSERC) are gratefully acknowledged.

Local atomic structures in grain boundaries of bulk nanocrystalline aluminium: A molecular dynamics simulation study

The microstructures of grain boundaries (GBs) in bulk nanocrystalline aluminium have been investigated by a large-scale molecular dynamics method. Bulk nanocrystalline aluminium is obtained directly by liquid quenching at an appropriate cooling rate, which has narrow grain-size distribution and high-angle GBs. It is found that up to 89.75% GB atoms (named as GB1 atoms) are located at the nearest-neighbour coordination shell around nanograins; others (named as GB2 atoms) are mainly at triple junctions. Local atomic structures in the GBs are quantified in terms of a recently developed method, in which the neighbours of an atom are identified with a parameter-free topological criterion rather than a fixed cut-off distance rc. The results demonstrate that though there are a large number of different cluster types in both the GB1 and the GB2 regions, only a few ones with FCC-like order appear with high frequency in the GB1 region and play a crucial role in the microstructural feature of the GB1. The GB1 region displays short-to-long range order. The GB2 region presents ICO- and BCC-like short-range orders whose degrees are in between the liquid and amorphous, but the medium-range order at the cluster-scale is very weak.

Grain growth studies on nanocrystalline Ni powder

The microstructure of nanocrystalline Ni powder produced by ball-milling and its thermal stability were investigated by applying different methods of X-ray diffraction line-profile analysis: single-line analysis, whole powder-pattern modelling and the (modified) Warren–Averbach method were employed. The kinetics of grain growth were investigated by both ex-situ and in-situ X-ray diffraction measurements. With increasing milling time, the grain-size reduction is accompanied by a considerable narrowing of the size distribution and an increase in the microstrain. Upon annealing, initial, rapid grain growth occurs, accompanied by the (almost complete) annihilation of microstrain. For longer annealing times, the grain-growth kinetics depend on the initial microstructure: a smaller microstrain with a broad grain-size distribution leads to linear grain growth, followed by parabolic grain growth, whereas a larger microstrain with a narrow grain-size distribution leads to incessant linear grain growth. These effects have been shown to be incompatible with grain-boundary curvature driven growth. The observed kinetics are ascribed to the role of excess free volume at the grain boundaries of nanocrystalline material and the prevalence of an “abnormal grain-growth” mechanism.

Fe-VC-Fe3C nanocomposites produced by mechanical synthesis from various starting components

Methods of X-ray diffraction, Mossbauer spectroscopy, and electron and atomic force microscopy have been used to study the sequence of structural and phase transformations upon mechanical alloying, annealing, and compacting of iron-vanadium-carbon alloys produced from mixtures of various compositions, such as powders of Fe (70 at %) and VC (30 at %); powders of pure elements of Fe (70 at %), V (15 at %), and graphite (15 at %); powders of Fe (70 at %) and V (15 at %) and toluene. It has been shown that in all cases the mechanical alloying results in the formation of nanocomposite powders with a complex phase composition representing a mixture of an α-Fe-based solid solution, carbide-based X-ray amorphous phase, and vanadium carbide VC. The annealing and compacting lead to the formation of an Fe-VC-Fe3C nanocomposite. The use of liquid organic media as the source of carbon makes it possible to obtain materials with a narrow grain-size distribution and a uniform spatial distribution of carbide phases, which results in high values of microhardness, to 12 GPa.

Flow processes and sedimentation associated with erosion and filling of sinuous submarine channels

This article uses measurements from a three-dimensional exposure of a sinuous submarine channel and its fill to document, for the first time, how flow properties and sedimentation differ between erosional and filling stages. Two units, recording this sequential evolution, are documented. Unit 1 records gravity flows that deepened and laterally migrated the channel, resulting in the deposition of point bars, with coarsening-upward profiles, on the inner part of channel bends. These gravity flows were mud-rich with a wide grain-size distribution. Flow heights exceeded the depth of the channel resulting in the deposition of levees. Strong secondary flow is evident with a helical pattern reversed to their subaerial counterparts. Strata in point bars and levees are inclined and deposited primarily by tractive processes. Unit 2 records gravity flows that filled the channel. These gravity flows were sand-rich with a relatively narrow grain-size distribution. Flow heights scaled to the depth of the channel, and they contain no evidence for secondary flow. Associated strata are horizontal and deposited primarily from suspension.

Nanoparticle Arrays: Biotemplated Magnetic Nanoparticle Arrays (Small 2/2012)

A biomineralization protein from magnetotactic bacteria (Mms6) used to control both the formation and location of magnetic nanoparticles in a patterned array. Mms6 immobilized on a patterned surface templates high-quality, crystalline magnetite particles with a narrow grainsize distribution and consistent magnetic behavior under relatively mild conditions. These particles are ferrimagnetic and may be exchange-coupled on the surface, forming multiparticle attraction/repulsion zones. The biomineralization of nanomaterials in patterned arrays on surfaces using various specific proteins and peptides with templating ability could be used as a more environmentally friendly methodology to develop micro- and nanoscale devices.

Microstructure dependence of the magnetic properties of sintered Ni–Zn ferrites by solid-state reaction doped with V2O3

In order to improve the frequency range operation of Ni–Zn ferrites with the Ni0.7Zn0.3Fe2O4 stoichiometry in this study, they were doped with V2O3 at different concentrations (0, 0.25, 0.50, and 0.75 wt%). The samples were prepared by the solid-state reaction at 1250 °C for 24 h. The content and location of Vanadium in these ferrites allow us to determine its influence on their microstructure and magnetic properties. A single cubic spinel phase with lattice parameter variation was determined by the refinement of X-ray diffraction patterns. This refinement was achieved using the Rietveld method. The lattice parameter presents a slight enhancement with increasing Vanadium content up to 0.50 wt% of V2O3. The increase of intragrain porosity and the segregation of Vanadium at the grain boundary in samples with higher concentration of Vanadium show a narrow grain-size distribution that leads to a resonant character of the magnetic domain wall. A wide grain-size distribution determined in lower concentration of Vanadium results in a mixed resonant-relaxation dispersion. The use of V2O3 as a dopant in Ni–Zn ferrites increases the frequency operation and coercivity, Hc, without abruptly degrading the saturation magnetization, Ms. We, therefore conclude, that Vanadium may be used as a strong dopant for the preparation of ferrites for any particular high-frequency application.

Preparation and Characterization of Ca&lt;sub&gt;0.8&lt;/sub&gt;Sr&lt;sub&gt;0.2&lt;/sub&gt;ZrO&lt;sub&gt;3&lt;/sub&gt; Powders Prepared by Soft Chemical Route

Precursors of calcium strontium zirconate (Ca0.8Sr0.2ZrO3) were synthesized by oxalate coprecipitation method. TG-DTA was used to characterize the thermal decomposition behaviors of the precursors. The XRD results revealed that the powders crystallized as cubic Ca0.8Sr0.2ZrO3 with increasing heating temperature up to 1000°C. Calcium strontium zirconate ceramics were obtained under conventional sintering conditions by using the as-prepared Ca0.8Sr0.2ZrO3 powders. The SEM micrographs of the ceramics sintered at 1450oC exhibited narrow grain-size distribution with the average grain size around 0.7 4m. The dielectric properties showed that, dielectric constant of the Ca0.8Sr0.2ZrO3 was about 24.0 and dielectric loss was 0.002 at the frequency of 1GHz and the room temperature.

Preparation of porous hydroxyapatite scaffolds

In this work, the sintering and grain growth of hydroxyapatite green bodies are analyzed in order to identify the optimum heat treatments for the preparation of porous hydroxyapatite scaffolds. Sintering in air at temperatures ranging between 1100 and 1200 °C yields dense materials with narrow grain-size distributions. The scaffolds are formed by the infiltration of polymer foams with hydroxyapatite slurries or by robocasting, a novel rapid-prototyping technique. Examples of the microstructures achieved with each approach are presented. It is observed that both techniques can be used to fabricate scaffolds with adequate pore size to promote bone ingrowth.

Structure and insertion properties of disordered and ordered LiNi0.5Mn1.5O4 spinels prepared by wet chemistry

We present the synthesis, characterization, and electrode behavior of LiNi0.5Mn1.5O4 spinels prepared by the wet-chemical method via citrate precursors. The phase evolution was studied as a function of nickel substitution and upon intercalation and deintercalation of Li ions. Characterization methods include X-ray diffraction, SEM, Raman, Fourier transform infrared, superconducting quantum interference device, and electron spin resonance. The crystal chemistry of LiNi0.5Mn1.5O4 appears to be strongly dependent on the growth conditions. Both normal-like cubic spinel [Fd3m space group (SG)] and ordered spinel (P4132 SG) structures have been formed using different synthesis routes. Raman scattering and infrared features indicate that the vibrational mode frequencies and relative intensities of the bands are sensitive to the covalency of the (Ni, Mn)-O bonds. Scanning electron microscopy (SEM) micrographs show that the particle size of the LiNi0.5Mn1.5O4 powders ranges in the submicronic domain with a narrow grain-size distribution. The substitution of the 3d8 metal for Mn in LiNi0.5Mn1.5O4 oxides is beneficial for its charge–discharge cycling performance. For a cut-off voltage of 3.5–4.9 V, the electrochemical capacity of the Li//LiNi0.5Mn1.5O4 cell is ca. 133 mAh/g during the first discharge. Differences and similarities between LiMn2O4 and LiNi0.5Mn1.5O4 oxides are discussed.

LiMn 2− yCo yO 4 (0 ≤ y ≤ 1) intercalation compounds synthesized from wet-chemical route

We present the synthesis, characterization and electrode behaviour of LiMn 2− y Co y O 4 (0 ≤ y ≤ 1) spinel oxides prepared by the wet-chemical route assisted by carboxylic acid. The phase evolution was studied as a function of the cobalt substitution and the modification on the intercalation and deintercalation of Li ions. Characterization methods include TG-DTA, XRD, SEM, Raman, FTIR, and SQUID. LiMn 2− y Co y O 4 samples crystallize with the cubic spinel-like structure ( Fd3 m S.G.). Raman scattering and FT-infrared spectroscopy indicate that the vibrational mode frequencies and relative intensities of the bands are sensitive to the covalency of the (Co, Mn)–O bonds. MEB micrographs show that the particle dimension of the LiMn 2− y Co y O 4 powders ranges in the sub-micron-sized domain with a narrow grain-size distribution. The overall electrochemical capacity of LiMn 2− y Co y O 4 oxides have been reduced due to the 3d 6 metal substitution. However, a more stable charge–discharge cycling performances has been observed when the electrodes are charged up to 4.3 V as compared to the performance of the native oxide. For such a cut-off voltage, the charge capacity of the Li//LiMn 1.8Co 0.2O 4 cell is ca. 101 mA h/g. Differences and similarities between LiMn 2O 4 and Co-substituted oxides are discussed there from.