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A zeolitic imidazolate framework-8 (ZIF-8) layer was introduced as a surface molecular separator to grant the selective gas-sensing ability to thin-film sensor material composed of SnO2 nanosheets. ZIF-8 possesses a molecular sieving ability, which is in the range of approximately 4.0–4.2 A. Compared to a SnO2 nanosheet gas sensor, a ZIF-8/SnO2 nanosheet gas sensor exhibited a decreased sensor signal response when the gas molecular sizes were large, e.g., C3H6 (4.120 A), 1-C4H8 (5.430 A), and C9H18O (12.011 A). However, the ZIF-8/SnO2 nanosheet sensor signal response to smaller-sized gas molecules, such as C2H4 (3.058 A), was slightly increased due to electron transfer at the ZIF-8 and SnO2 interface. Therefore, the control of gas selectivity based on molecular size was realized by introducing ZIF-8 as a surface molecular separator. These results pave the way for selective gas sensing in various types of applications that depend on gas selectivity.

Propylene is industrially produced in a mixture with propane and generally separated from the mixture via distillation. However, because distillation is an energy-consuming process, a more efficient separation process should be developed to mitigate both carbon dioxide (CO2) emissions and production costs. In this study, a two-stage membrane-separation process was designed, and its CO2 emission and production costs were evaluated. The separation processes were designed to minimize energy consumption using different membrane combinations (two recently developed membranes each). To evaluate the separation processes using various membrane combinations, two indicators, i.e., CO2 emissions and total annual costs (TACs), were estimated based on the process simulation (Pro/II, version 10.1.1) results, including energy consumptions, operation expenditure, and capital expenditure. These results were compared to the distillation processes as benchmarks, and the advantages of the membrane-separation process were discussed. In the comparison, carbon taxes were implemented for assessing these two independent indicators as a single indicator, i.e., TAC with carbon tax. Furthermore, using the same scheme, model membranes were also employed in the two-stage membrane-separation process as case studies of technological forecasts.

Original teaching materials with dot codes were created for use with autistic children with intellectual and expressive language disabilities. One of the authors (S. I.) created “Post-it” sticker icons on which dot codes were printed and shared these with teachers of children with autism spectrum disorders (ASD). Each sticker icon was linked with up to four multimedia mediums of expression, such as a movie, in addition to up to four voices/sounds. Touching a dot code icon with a speaking-pen enables audios to be replayed, and touching a dot code icon with a dot-code reader with Bluetooth functionality enables multimedia to be replayed on iOS and Windows OS devices. New software to create self-made teaching materials with dot codes was developed by Gridmark Inc., with the help of author S. I. Basic information on creating original teaching materials using this newly developed software and its use in schools for students with ASD are presented in this chapter.

Zeolitic imidazolate framework-7-III (ZIF-7-III), a well-known metal–organic framework (MOF), has attracted attention as gas separation membrane material. For practical realization, it is necessary to adjust the aspect ratio of ZIF-7-III particles because it can affect the gas separation performance. In this study, we demonstrate the control of the aspect ratio by changing the synthesis condition using microemulsion prepared from n-alkyltrimethylammonium bromide as a surfactant, 1-hexanol as a co-surfactant, heptane as a continuous phase, and water as a dispersed phase. When cetyltrimethylammonium bromide (CTAB) was used as surfactant, ZIF-7-III particles with particle sizes of 10–20 μm were prepared by changing the water and CTAB concentration. In synthesis using four types of surfactants, the particle size of the resultant ZIF-7-III particles increased from 7 μm to 26 μm, and the aspect ratio increased from 4.9 to 11 with an increase in the hydrophobic chain length from C12 to C18. The control of the morphology is attributed to the adsorption of surfactants on hydrophobic (001) facets of ZIF-7-III, which is currently hypothesized to be monolayer or bilayer. The supply of the reactants could be hindered further with the increase of the hydrophobic chain length of the surfactants in either cases. ZIF-7-III particles obtained in this study can be exfoliated into nanosheets, which will accelerate the development of ZIF-7-III-based molecular–sieve gas separation membranes.

This study examines the finite $F$-representation type (abbr. FFRT) property of a two-dimensional normal graded ring $R$ in characteristic $p>0$, using notions from the theory of algebraic stacks. Given a graded ring $R$, we consider an orbifold curve $\mathfrak C$, which is a root stack over the smooth curve $C=\text{Proj} R$, such that $R$ is the section ring associated with a line bundle $L$ on $\mathfrak C$. The FFRT property of $R$ is then rephrased with respect to the Frobenius push-forwards $F^e_*(L^i)$ on the orbifold curve $\mathfrak C$. As a result, we see that if the singularity of $R$ is not log terminal, then $R$ has FFRT only in exceptional cases where the characteristic $p$ divides a weight of $\mathfrak C$., 25 pages, exposition on stacks added, to appear in Adv. Math

ZIF-8 membranes are currently attracting attention for the separation of propylene/propane based on the molecular sieve effect. We have recently reported the preparation of ZIF-8 membranes using the counter-diffusion method, which is advantageous in reducing defects in the selective layer. In the present study, ZIF-8 membranes were prepared at the interface of miscible and immiscible pairs of solvents such as water/methanol and water/1-octanol, respectively. ZIF-8 membranes prepared from the immiscible pair of water and 1-octanol showed a propylene permeance of 5.2 × 10−9 mol m−2 s−1 Pa−1 and a propylene/propane permselectivity of 7.2 at 25 °C. As for the ZIF-8 membrane prepared by the initial reaction using the immiscible pair of water/1-octanol and the successive reaction using the miscible pair of water/methanol mixture, the average propylene permeance and average propylene/propane permselectivity increased to 1.2 × 10−8 mol m−2 s−1 Pa−1 and 20 at 25 °C, respectively. The successive reactions in water/1-octanol and water/methanol mixtures successfully decreased the defects in the ZIF-8 selective layer, resulting in high propylene permeance and high permselectivity for propylene/propane. The structure and gas permeation properties were also thoroughly characterized.

In this paper, a powerful and simple method to evaluate quantitatively the influence of the non-ideal contribution of the hydrogen permeation under diffusion control is provided. For this purpose, a Non-Ideality Index (α) is defined as the ratio of the non-ideal permeability term and the overall permeability, this leading to a direct quantification of the non-ideal effect in membrane. The used methodology is described in detail by using experimental data of a real Pd-membrane. From these data, the parameters that characterise permeability as a function of temperature and pressure – i.e., intrinsic permeability (b) and non-ideal factor (a) – are evaluated, highlighting their higher suitability in describing the membrane behaviour with respect to the usual empirical parameters used by the majority of researchers (i.e., pressure exponent and corresponding permeability). It is underlined that the proposed approach is particularly effective for modelling membrane contactors and reactors, where the empirical Sieverts-type law cannot be used because the large difference of pressure and temperature could lead the membrane behaviour to dramatically change even at different locations of the same device.

We introduce a research on steering dampers using MR fluid (Magnetorheological Fluid). In recent years, steering dampers have been used in on-road and off-road motorcycles. Steering dampers stabilize the front end of motorcycles. The advantage of a steering damper is increased stability, but hydraulic steering dampers give rise to the problem of 'Heavy Steering'. In order to resolve this heavy steering, we need to set the restrictions on the maximum damping force and avoid it from interfering when the rider is steering. However only reducing the damping force will lead to insufficient damping force when the handle, unresponsive because of kickback, shakes. We solved this problem with the development of an electric control damper which generates sufficient damping force at low steering angle rates and also allows for mechanically limiting the maximum damping force. The damper design uses "Direct Shear Mode" and features a steering angle sensor built into the damper, which results in easier and smoother steering. To test its effectiveness, we installed our new steering damper and asked for feedback from riders. From the received feedback, we were able to confirm the effectiveness and efficiency of our new design as well as its superiority over other traditional designs. In particular, we were able to improve stability when entering a corner or riding over gaps by generating more damping force from a low steering angle rate in comparison to traditional dampers. We also succeeded in keeping the nimble handling while riding by reducing the maximum damping force. Language: en

A uniquely microstructured membrane, a metal–organic framework (MOF) layer within the porous support, was prepared by a counter-diffusion method. The MOF-based membrane prepared from the copper benzene tricarboxylate (Cu-BTC), one of the MOFs, exhibited excellent gas perm-separation properties with an ideal H2/CH4 selectivity of 153.

This study is focused on modeling and simulation of hierarchically structured catalytic media with macro- and meso-pores. The hierarchical structures are expected to enhance the contact between reactants and active catalytic sites. However, heterogeneous simulations of such structures are not computationally feasible for a practical scale, so that a multi-scale approach involving a pseudo-homogeneous approximation is required. This work aims at determining a suitable form for effectiveness factor in the reaction rate and effective diffusivity to be used in a pseudo-homogeneous approximation. To do that, computational fluid dynamics (CFD) simulations of hierarchical structure of particles are carried out in both heterogeneous and homogeneous mode within 240–300 °C and Thiele modulus around 2.4 or less. The analysis is applied to decane oxidation as representative of the oxidation of exhausted gas from Diesel engines. After providing a validation of the analysis on a single catalyst spherical particle, simulations in heterogeneous mode are carried out under isothermal conditions. The results suggest that the effective diffusivity for the pseudo-homogeneous approximation should include porosity and tortuosity of ensemble, which is evaluated considering the particles as dense. Additionally, detailed profile analysis suggests that the analytical expression of the effectiveness factor valid for spherical particles under isothermal conditions could be used in the pseudo-homogeneous approximation. Then, simulations in homogeneous mode are carried out under both isothermal and non-isothermal conditions to confirm the above-cited suggestions. The obtained results demonstrate the suitability of the chosen effectiveness factor and effective diffusivity.

We prove that F-blowups of any F-regular surface singularity coincide with the minimal resolution.

Computational fluid dynamics (CFD) simulations of a reactive catalytic layer of micrometer-sized particles with a submicrometer interparticle distance for decane oxidation are described. The investigation used two main approaches. The heterogeneous approach simulates particles at the reactive particle surface, by use of a monodispersed face-centered cubic structure of eight unit cells in series. In contrast, the pseudohomogeneous approach investigates the particle system as a homogeneous system (approximation) having dimensions and geometrical properties (tortuosity and porosity) identical to those of the heterogeneous one. Heterogeneous system results show that mass transfer resistance can be regarded as negligible in the whole range of parameters investigated (temperature and interparticle distance). Particularly, the difference in results obtained by the two approaches is negligible up to the highest temperature considered (400 °C), with a maximum discrepancy of about 2.4%. An analogous result is found...

We synthesized and characterized for the first time an ampholytic ion-recognition linear copolymer of [3-(methacryloylamino)propyl]trimethylammonium chloride (MAPTAC), acrylic acid (AA), and benzo[18]crown-6-acrylamide (BCAm). In this copolymer, the MAPTAC unit has a positive charge. The AA unit has a negative charge that depends on the pH. The crown receptor of the BCAm unit forms a complex with specific ions such as Ba2+ because of the high complex formation constant which behaved like a fixed positive charge. Thus, the copolymers behaved as an ion-recognition polyampholytes and shrank at a pH equal to the isoelectric point (IEP), which shifted to a higher pH when the BCAm complexed with a cation. At that time, the BCAm also became hydrophilic with water of hydration accompanied by the cation. As a result of the combination of these two effects, we found that the reverse behaviors of swelling and shrinking occurred at different pHs in response to the same ion signal.

We found that protons rapidly conduct through unfreezable and bound water in a pore-filling electrolyte membrane (PF-membrane), although many ions usually conduct through free water contained in polymer electrolytes. PF-membrane is a unique membrane that can suppress the swelling of filled sulfonated poly(arylene ether sulfone) (SPES) because of its rigid polyimide substrate. Based on low-temperature DSC measurements, this strong suppression of swelling resulting from the special structure of the polymer electrolyte results in unfreezable and bound water only; it does not contain any free water. Protons rapidly conduct through this structure. In addition, the activation energy of the proton conduction decreased from 16.3 to 9.1 kJ/mol in proportion to the increase in the ion exchange capacity (IEC) of the filled SPES, unlike the almost constant values of the SPES-cast membranes. This tendency of PF-membrane occurred because of the structure of the membrane, where the concentration of the sulfonic acid groups increased with increase in IEC, which became possible by squeezing free water using the swelling suppression of filled SPES. Without being constrained by the PF-membrane, this unique proton conduction through the structured water and highly concentrated sulfonic acid groups will help to develop future polymer electrolytes, particularly in the fuel cell field where protons need to conduct at various conditions such as temperatures below 0 degrees C, combined high temperature and low humidity, and the presence of fuels.

We present two applications of a characteristic p analog of multiplier ideals, which is a generalization of the test ideal in the theory of tight closure. Namely, we give alternative proofs to Smith's result on base-point-freeness of adjoint bundles in characteristic p > 0 and results on uniform behavior of symbolic powers in a regular local ring due to Ein, Lazarsfeld and Smith, and Hochster and Huneke.

The test ideal $\tau(R)$ of a ring $R$ of prime characteristic is an important object in the theory of tight closure. In this paper, we study a generalization of the test ideal, which is the ideal $\tau(\a^t)$ associated to a given ideal $\a$ with rational exponent $t \ge 0$. We first prove a key lemma of this paper, which gives a characterization of the ideal $\tau(\a^t)$. As applications of this key lemma, we generalize the preceding results on the behavior of the test ideal $\tau(R)$. Moreover, we prove an analog of so-called Skoda's theorem, which is formulated algebraically via adjoint ideals by Lipman in his proof of the "modified Brian\c{c}on--Skoda theorem.", Comment: 11 pages, AMS-LaTeX; v.2: minor changes, to appear in Nagoya Math. J

For an algebraic variety $X$ in characteristic $p>0$, the push-forward $F^{e}_{*}\mathcal{O}_{X}$ of the structure sheaf by an iterated Frobenius endomorphism $F^{e}$ is closely related to the geometry of $X$. We study the decomposition of $F^{e}_{*}\mathcal{O}_{X}$ into direct summands when $X$ is obtained by blowing up the projective plane $\mathbb{P}^{2}$ at four points in general position. We explicitly describe the decomposition of $F^{e}_{*}\mathcal{O}_{X}$ and show that there appear only finitely many direct summands up to isomorphism, when $e$ runs over all positive integers. We also prove that these summands generate the derived category $D^{b}(X)$. On the other hand, we show that there appear infinitely many distinct indecomposable summands of iterated Frobenius push-forwards on a ten-point blowup of $\mathbb{P}^{2}$.

We investigate the relationship of F-regular (resp. F-pure) rings and log terminal (resp. log canonical) singularities. Also, we extend the notions of F-regularity and F-purity to “F-singularities of pairs." The notions of F-regular and F-pure rings in characteristic p > 0 p > 0 are characterized by a splitting of the Frobenius map, and define some classes of rings having “mild" singularities. On the other hand, there are notions of log terminal and log canonical singularities defined via resolution of singularities in characteristic zero. These are defined also for pairs of a normal variety and a Q \mathbb Q -divisor on it, and play important roles in birational algebraic geometry. As an analog of these singularities of pairs, we introduce the concept of “F-singularities of pairs," namely strong F-regularity, divisorial F-regularity and F-purity for a pair ( A , Δ ) (A,\Delta ) of a normal ring A A of characteristic p > 0 p > 0 and an effective Q \mathbb Q -divisor Δ \Delta on Spec ⁡ A \operatorname {Spec} A . The main theorem of this paper asserts that, if K A + Δ K_{A}+\Delta is Q \mathbb Q -Cartier, then the above three variants of F-singularities of pairs imply KLT, PLT and LC properties, respectively. We also prove some results for F-singularities of pairs which are analogous to singularities of pairs in characteristic zero.

We extend Kawachi's invariant for reduced points on a normal suface to an invariant defined for possibly non-reduced zero-dimensional closed subschemes (or fat points) on a surface with rational singularities. We give an upper bound of this invariant in terms of the length of the fat point and the discrepancy of the minimal resolution. As an application we prove a Reider-type theorem for k-very ampleness on surfaces with rational singularities.

We give a quick new proof of Wahl's vanishing theorem for rational surface singularities, using prime characteristic technique. Our method also gives a criterion for F-rationality in dimension 2.

The notions of F -rational and F -regular rings are defined via tight closure, which is a closure operation for ideals in a commutative ring of positive characteristic. The geometric significance of these notions has persisted, and K. E. Smith proved that F -rational rings have rational singularities. We now ask about the converse implication. The answer to this question is yes and no. For a fixed positive characteristic, there is a rational singularity which is not F -rational, so the answer is no. In this paper, however, we aim to show that the answer is yes in the following sense: If a ring of characteristic zero has rational singularity, then its modulo p reduction is F -rational for almost all characteristic p . This result leads us to the correspondence of F -regular rings and log terminal singularities.

An aluminum tappet, an aluminum spring retainer, and a thin sintered adjusting shim were developed to produce a lighter valve train. By utilizing these parts, valve train inertia mass was reduced by 28%. Moreover, cam profile and valve spring specifications were redesigned fully to employ the reduced inertia mass for a reduced friction loss. The overall friction loss was reduced by 40%, and this friction loss was achieved in the roller rocker arm system.

LetR be a two-dimensional normal graded ring over a field of characteristicp>0. We want to describe the tight closure of (O) in the local cohomology moduleH R+ 2 (R) using the graded module structure ofH R+ 2 (R). For this purpose we explore the condition that the Frobenius mapF: [H R+ 2 (R)]n→[H R+ 2 (R)]pninduced on graded pieces ofH R+ 2 (R) is injective. This problem is treated geometrically as follows: There exists an ample fractional divisorD onX=Proj (R) such thatR=R (X, D)= ⊕ n≥0H0(X O X (n D)). Then the above map is identified with the induced Frobenius on the cohomology groups Our interest is the casen0 is defined via tight closure and is expected to characterize rational singularities. We ask if a modulop reduction of a rational signularity in characteristic 0 isF-rational forp≫0. Our result answers to this question affirmatively and also sheds light to behavior ofF-rationality in smallp.

We study F-blowups of non-F-regular normal surface singularities. Especially the cases of rational double points and simple elliptic singularities are treated in detail., 25 pages, v2: minor revision

The contribution of diffusive separation of propylene/propane was determined from the permeation properties of zeolitic-imidazolate framework-8 (ZIF-8) 1 membranes. These membranes were prepared using a counter diffusion method, resulting in the formation of an 80 μm-thick ZIF-8 layer on the outermost section of a porous α-alumina capillary substrate. Single-component gas permeation properties were investigated using helium, hydrogen, carbon dioxide, oxygen, nitrogen, methane, propylene, and propane at temperatures ranging from 298 to 363 K. The molecular sieve gas permeation properties of the ZIF-8 membranes increased with reaction time, which is consistent with the evolution of ZIF-8 crystal formation. The ZIF-8 membrane permeances of hydrogen and propylene reached 9.1×10 −8 and 2.5×10 −9 mol m −2 s −1 Pa −1 , respectively. The ideal separation factors for hydrogen/propane and propylene/propane at 298 K were found to be 2000 and 59, respectively. The diffusion separation factor increased with decreasing temperature, reaching 23, while the solution separation factor remained 2.7. Therefore, the separation of propylene/propane was attributed to be mainly governed by diffusive separation.