Mixture design concept and mechanical characteristics of PS ash–cement-treated clay based on the water absorption and retention performance of PS ash

In an attempt to reduce environmental impact, paper sludge ash (PS ash) has recently been studied for its complementary reuse with cement for soil stabilization. In order to establish the optimal mixture design for combining PS ash and cement in soils, a detailed investigation into the stabilizing mechanism is required. To assess the combined effects of PS ash and cement on the strength development of stabilized clay soil, referred to as PS ash–cement-treated clay, a new critical parameter, the unabsorbed and unretained clay-water/cement ratio W*/C, was proposed. To determine W*/C, a new testing method for evaluating the water absorption and retention performance of PS ash was developed. It was revealed that the water absorption and retention rate W_ab of PS ash increased with curing time. Unconfined compression tests conducted on the PS ash–cement-treated clay with various water-cement–PS ash mixture proportions and different curing times affirmed that the strength development was fundamentally governed by the parameter W*/C. This suggests that the water absorption and retention rate W_ab obtained by the developed method is an essential material parameter in the mixture design for the PS ash–cement-treated clay. It was also found that the effect of the hybrid treatment method, which uses both cement and PS ash, was better than that of the method which uses cement alone, particularly under high W*/C conditions. This indicates that the water absorption and retention performance of PS ash can be fully utilized when the mixture has sufficient unabsorbed and unretained water for cement hydration.     

Coherent lattice vibrations in single-walled carbon nanotubes

We have generated and detected coherent lattice vibrations in single-walled carbon nanotubes corresponding to the radial breathing mode (RBM) using ultrashort laser pulses. Because the band gap is a function of diameter, these RBM-induced diameter oscillations cause ultrafast band gap oscillations, thereby modulating the interband excitonic resonances at the phonon frequencies (3-9 THz). Excitation spectra show a large number of pronounced peaks, allowing the determination of the chiralities present in particular samples and relative population differences of particular chiralities between samples.     

Spout eyes formed by an emerging gas plume at the surface of a slag-covered metal melt

This article deals with the spout eyes developing, at the surface of a metal melt, in the ladle during argon stirring. Cold model experiments involving a mercury bath with an oil layer as slag and industrial experiments on a 350 t steel ladle have been carried out. The eye geometry as measured with a video technique is highly dynamic. The time average of the free surface area and the time fraction of complete coverage have been determined and are represented with dimensionless correlations.     

Velocity measurements of reactive and non‐reactive flows by NO‐LIF method using NO2 photodissociation

Velocities of reactive and non‐reactive flows, where NO₂ molecules were seeded, were measured by a NO‐based Laser Induced Fluorescence (LIF) method. NO₂ dilute gases were injected from a round tube with an inner diameter of 2 cm and its flow rate was 10 liters/minute or 20 liters/minute. Experiments were performed for 4 conditions—non‐reactive flows of NO₂ dilute gases at two flow rates, an unburnt gas flow of the premixed flame with NO₂ addition, and an unburnt gas flow of the diffusion flame with NO₂ addition. NO molecules were produced in flows by planar emissions of 355 nm laser rays from an Nd:YAG laser system, and NO‐LIF images were taken in a pre‐determined delay. An ICCD camera, a dye laser excited by an excimer laser, and Nd:YAG laser were strictly synchronized by a pulse generator. NO‐LIF signals, which were emitted by photochemically produced NO from NO₂, were strong enough to measure the NO displacements in the case of non‐reactive flows, while with only a few ppm concentrations of NO₂ added it was possible to measure the velocity in detail. Although fluctuations of NO trajectories were observed at the flow rate of 20 liters/minute, instantaneous velocities were measured accurately. In the case of the unburnt gas of the diffusion flame, NO‐LIF signals were also strong, and profiles of NO produced by NO₂ photodissociation were clearly measured. Profiles of NO produced by NO₂ photodissociation in the unburnt gas of the premixed flame were also clearly measured, even in the vicinity of the reaction zone. It can be seen that velocities were measured correctly in the unburnt regions of the premixed and the diffusion flames. With this method, it was possible to measure velocities of both steady and unsteady flows. © 2004 Wiley Periodicals, Inc. Heat Trans Asian Res, 34(1): 40–52, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20038     

Two-dimensional spin-exchange solid-state NMR study of the crystal structure of cellulose II

A two-dimensional (2D) ¹³C-¹³C spin-exchange NMR experiment was applied to the uniformly ¹³C-enriched cellulose II in order to obtain interatomic distance information in the cellulose II crystal. A radio frequency-driven recoupling (RFDR) rotor-synchronized π pulse sequence was incorporated during the mixing time of the 2D experiment. The 2D spin-exchange NMR recorded with a short mixing time (0.80-2.58 ms) provided the correlations between a pair of strongly coupled ¹³C spins such as neighbor carbon nuclei. This spectrum enabled us to assign all ¹³C resonance lines of two kinds of anhydroglucose residues A and B in the structure of cellulose II. On the basis of the ¹³C resonance assignment of residues A and B, the interatomic distances from each C1 to the other carbon nuclei were compared by measuring the 2D spectra recorded with longer mixing times (5.12-20.48 ms). As a result, it was revealed that the respective residues A and B are composed of independent chains (-A-A- and -B-B- repeating units) and that there are no -A-B- repeating units in the chain. This experimental technique is expected to be applicable to conformation analysis of polysaccharides as well as the other cellulose polymorphs.     

Combined ultrasonic elastic wave velocity and microtomography measurements at high pressures

Combined ultrasonic and microtomographic measurements were conducted for simultaneous determination of elastic property and density of noncrystalline materials at high pressures. A Paris-Edinburgh anvil cell was placed in a rotation apparatus, which enabled us to take a series of x-ray radiography images under pressure over a 180° angle range and construct accurately the three-dimensional sample volume using microtomography. In addition, ultrasonic elastic wave velocity measurements were carried out simultaneously using the pulse reflection method with a 10° Y-cut LiNbO(3) transducer attached to the end of the lower anvil. Combined ultrasonic and microtomographic measurements were carried out for SiO(2) glass up to 2.6 GPa and room temperature. A decrease in elastic wave velocities of the SiO(2) glass was observed with increasing pressure, in agreement with previous studies. The simultaneous measurements on elastic wave velocities and density allowed us to derive bulk (K(s)) and shear (G) moduli as a function of pressure. K(s) and G of the SiO(2) glass also decreased with increasing pressure. The negative pressure dependence of K(s) is stronger than that of G, and as a result the value of K(s) became similar to G at 2.0-2.6 GPa. There is no reason why we cannot apply this new technique to high temperatures as well. Hence the results demonstrate that the combined ultrasonic and microtomography technique is a powerful tool to derive advanced (accurate) P-V-K(s)-G-(T) equations of state for noncrystalline materials.     

Water Balance Study and Irrigation Strategies for Sustainable Management of a Tropical Ethiopian Lake: A Case Study of Lake Alemaya

Lake Alemaya in the Ethiopian Highlands has historically provided the surrounding area with water for domestic use, irrigation, and livestock and has served as a local fishery tank. Increasing irrigation and domestic water use, change in the local climate and changes in the surrounding land cover are believed to be the causes of Lake Alemaya’s demise. Expansion of major irrigated crops in particular chat (Catha Edulis), potato and vegetables and non-judicious use of irrigation water in the Lake Alemaya watershed led to presumption that irrigation is partly responsible for the withdrawal of large quantity of water from the lake. Thus, water balance study of Lake Alemaya was carried out under presumed scenarios in order to study the possible trends and fluctuations of the lake water level in response to proposed scenarios. Further, it is essential to study the irrigation performance for developing optimal irrigation schedules in the study area to make the best use of available water for long term sustainability of the water resources of Lake Alemaya. It was identified that expansion of the irrigated area in general and chat cultivation in particular in the study area have been the key to sustainable management of lake water, hence its expansion during the past 37 years (1965–2002) was studied through interpretation of satellite data. Subsequently, performance evaluation of the small-scale irrigation practices for major irrigated crops was carried out. Optimal irrigation schedules for different crop seasons were also developed for these irrigated crops using CROPWAT software. It was found that chat area increased from 190 ha in 1996 to nearly 330 ha in 2002. Further, it was observed that 43% surface area of the lake has reduced within a span of 37 years. Overall, maximum irrigation intensity of chat, potato and vegetables is observed during the first irrigation season of the crop calendar. Particularly, in case of chat, irrigation performance indicators such as Relative Water Supply (RWS), Relative Irrigation Supply (RIS), Depleted Fraction (DF) and Overall Consumed Ratio (OCR) values indicated poor performance of irrigation practices. From the analysis, it was found that the application of a fixed irrigation depth and fixed irrigation interval combinations of (25 mm—25 day), (20 mm—20 day), or (20 mm—25 day) are recommended for chat in the study area. Optimal irrigation schedules were decided on the basis of combination of irrigation interval and depth that results in low loss of irrigation water with reasonable yield reduction. Thus, determination of appropriate water management strategy can ensure proper utilization of the available water resources and improve the water application efficiency of the small-scale irrigation practices around Lake Alemaya, Ethiopia.     

Three-dimensional parallel Turing machines

Informally, the parallel Turing machine (PTM) proposed by Wiedermann is a set of identical usual sequential Turing machines (STMs) cooperating on two common tapes: storage tape and input tape. Moreover, STMs which represent the individual processors of a parallel computer can multiply themselves in the course of computation. On the other hand, during the past 25 years or so, automata on a three-dimensional tape have been proposed as computational models of three-dimensional pattern processing, and several properties of such automata have been obtained. We proposed a three-dimensional parallel Turing machine (3-PTM), and dealt with a hardware-bounded 3-PTM whose inputs are restricted to cubic ones. We believe that this machine is useful in measuring the parallel computational complexity of three-dimensional images. In this article, we continue the study of 3-PTM, whose inputs are restricted to cubic ones, and investigate some of its accepting powers. This work was presented in part at the 12th International Symposium on Artificial Life and Robotics, Oita, Japan, January 25–27, 2007     

Hierarchies based on the number of cooperating systems of three-dimensional finite automata

The question of whether processing three-dimensional digital patterns is much more difficult than two-dimensional ones is of great interest from both theoretical and practical standpoints. Recently, owing to advances in many application areas, such as computer vision, robotics, and so forth, it has become increasingly apparent that the study of three-dimensional pattern processing is of crucial importance. Thus, the study of three-dimensional automata as a computational model of three-dimensional pattern processing has become meaningful. This article introduces a cooperating system of three-dimensional finite automata as one model of three-dimensional automata. A cooperating system of three-dimensional finite automata consists of a finite number of three-dimensional finite automata and a three-dimensional input tape where these finite automata work independently (in parallel). Those finite automata whose input heads scan the same cell of the input tape can communicate with each other, i.e., every finite automaton is allowed to know the internal states of other finite automata on the cell it is scanning at the moment. In this article, we continue the study of cooperating systems of three-dimensional finite automata, and mainly investigate hierarchies based on the number of their cooperating systems.     

Expression of Lymphatic Markers in the Berger’s Space and Bursa Premacularis

We previously reported that the bursa premacularis (BPM), a peculiar vitreous structure located above the macula, contains numerous cells expressing markers of lymphatic endothelial cells, such as podoplanin and LYVE-1. Herein, we examined the expression of lymphatic markers in the Berger’s space (BS), BPM, and vitreous core (VC). BS, BPM, and VC specimens were selectively collected in macular hole and epiretinal membrane patients during vitrectomy and were then immunostained with antibodies for podoplanin, LYVE-1, and fibrillin-1 and -2. By visualization using triamcinolone acetonide, the BS was recognized as a sac-like structure with a septum located behind the lens as well as BPM. Those tissues adhered to the lens or retina in a circular manner by means of a ligament-like structure. Immunostaining showed intense expression of podoplanin and LYVE-1 in the BS. Both BS and BPM stained strongly positive for fibrillin-1 and -2. The VC was faintly stained with antibodies for those lymph-node markers. Our findings indicate that both BS and BPM possibly belong to the lymphatic system, such as lymph nodes, draining excess fluid and waste products into lymphatic vessels in the dura mater of the optic nerve and the ciliary body, respectively, via intravitreal canals.