Attrition of Victorian brown coal during drying in a fluidized bed

Analyzing the attrition of Victorian brown coal during air and steam fluidized bed drying, the change in particle size distribution over a range of initial moisture contents (60% to 0%) and residence times (0 to 60 minutes) was determined. Dried at a temperature of 130°C with a fluidization velocity 0.55 m/s and an initial particle size of 0.5–1.2 mm, both fluidization mediums show a shift in the particle size distribution between three and four minutes of fluidization, with a decrease in mean particle size from 665 µm to around 560 µm. Using differential scanning calorimetry (DSC), the change in particle size has been attributed to the transition between bulk and non-freezable water (approximately 55% moisture loss) and can be linked to the removal of adhesion water, but not to fluidization effects. This is proved through the comparison of air fluidized bed drying, steam fluidized bed drying, and fixed bed drying—the fixed bed drying is being used to determine the particle size distribution as a function of drying. The results show the three drying methods produce similar particle size distributions, indicating that both fluidization and fluidization medium have no impact upon the particle size distribution at short residence times around ten minutes. The cumulative particle size distribution for air and steam fluidized bed dried coal has been modeled using the equation P_d = A₂ + (A₁ ? A₂)/(1 + (d/x₀)^p), with the resultant equations predicting the effects of moisture content on the particle size distribution. Analyzing the effect of longer residence times of 30 and 60 minutes, the particle size distribution for steam fluidized bed dried coal remains the same, while air fluidized bed dried coal has a greater proportion of smaller particles.     

Sliding mode cutting force regulator for turning processes

Continuous sliding mode control is applied to turning processes for cutting force regulation. The motivation of the use of the slide mode control scheme is to solve the nonlinearity problem caused by the feedrate override command element in the commercial CNC machine tool. When the adaptive control algorithm is applied to the commercial CNC machine tool, it is one of the practical methods that the programmed feedrate is overridden after the control algorithm is carried out. However, most CNC lathe manufacturers offer limited number of data bits for feedrate override, thus resulting in nonlinear behavior of the machine tools. Such nonlinearity brings ‘quantized' or discrete effect so that the optimal feedrate is rounded off before being fed into the CNC system. To compensate for this problem, continuous sliding mode control is applied. Simulation and experimental results are presented in comparison with those obtained from applying adaptive control which is a widely used approach in cutting force regulation. Adaptive control loses its effectiveness in the presence of nonlinearity since it generally requires linear parametrization of the control law or the system dynamics. Experiments are conducted under various machining conditions, subject to changes in spindle speed, material of work-piece, and type of machining process. The suggested slide mode controller shows smoother cutting force fluctuation, which cannot be achieved by the conventional adaptive controller. The experimental set-up reflects the emphasis on the practicality of the sliding mode controller. In order to avoid the use of a dynamometer in the course of measuring the cutting force, the indirect cutting force measuring system is used by means of feed drive servo-motor current sensing.     

Vaccination of Silver Sea Bream (Sparus sarba) against Vibrio alginolyticus: Protective Evaluation of Different Vaccinating Modalities

In order to develop more effective immunological strategies to prevent vibriosis of farmed marine fish in Hong Kong and southern China, various vaccine preparations including formalin-, phenol-, chloroform- and heat-killed whole cell bacterins and subcellular lipopolysaccharides (LPS), as well as different administration routes, were investigated. Fish immunized with the subcellular LPS exhibited the best protection [Relative Percent of Survival (RPS) = 100], while fish immunized with whole cell bacterins displayed varying degrees of protection (RPS ranged from 28 to 80), in descending order: formalin-killed > phenol-killed > heat-killed > chloroform-killed bacterins. Regarding various administration routes, fish immunized with two intraperitoneal (i.p.) injections exhibited the best protection, and the RPS values were 100 or 85 upon higher or lower doses of pathogenic V. alginolyticus challenges. Both oral vaccination and a combination of injection/immersion trial were also effective, which achieved relatively high protection (the RPS values ranged from 45 to 64.3). However, two hyperosmotic immersions could not confer satisfactory protection, especially when fish were exposed to the severe pathogenic bacteria challenge. Marked elevations of serum agglutinating antibody titer were detected in all immunized fish. Macrophage phagocytosis was enhanced significantly, especially in the fish immunized by formalin- and phenol-killed bacterins through various administration routes. Both adaptive (specific antibody) and innate (phagocytic activity) immunity elicited by different immunization strategies were in parallel with the degree of protection offered by each of them. Although all vaccination trials had no significant effect on the serum hematocrit and hemoglobin levels, the circulating lymphocyte counts were significantly elevated in the fish immunized with LPS, formalin- and phenol-killed bacterins. Serum cortisol levels appeared to be reduced in all immunized fish except the trial of hyperosmotic immersion, which indicated the stressful impact on vaccinated fish.     

Transcranial Magnetic Stimulation of the Supplementary Motor Area in the Treatment of Obsessive-Compulsive Disorder: A Multi-Site Study

Recently, strategies beyond pharmacological and psychological treatments have been developed for the management of obsessive-compulsive disorder (OCD). Specifically, repetitive transcranial magnetic stimulation (rTMS) has been employed as an adjunctive treatment in cases of treatment-refractory OCD. Here, we investigate six weeks of low frequency rTMS, applied bilaterally and simultaneously over the sensory motor area, in OCD patients in a randomized, double-blind placebo-controlled clinical trial. Twenty-two participants were randomly enrolled into the treatment (ACTIVE = 10) or placebo (SHAM = 12) groups. At each of seven visits (baseline; day 1 and weeks 2, 4, and 6 of treatment; and two and six weeks after treatment) the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) was administered. At the end of the six weeks of rTMS, patients in the ACTIVE group showed a clinically significant decrease in Y-BOCS scores compared to both the baseline and the SHAM group. This effect was maintained six weeks following the end of rTMS treatment. Therefore, in this sample, rTMS appeared to significantly improve the OCD symptoms of the treated patients beyond the treatment window. More studies need to be conducted to determine the generalizability of these findings and to define the duration of rTMS’ clinical effect on the Y-BOCS. Clinical Trial Registration Number (NCT) at www.clinicaltrials.gov: {"type":"clinical-trial","attrs":{"text":"NCT00616486","term_id":"NCT00616486"}}NCT00616486.     

Interactions of rhodium carbonyl compounds supported on inorganic oxides with CO,H2 and propylene

RhCl(CO)(PPh₃)₂, RhH(CO)(PPh₃)₃, and [RhClfCO)₂]₂ were supported on silica gel, γ-alumina, titania.and magensia in 3 to 5 wt % to study the interactions of rhodium carbonyl with the surface of inorganic oxides When trans-RhCI(CO)(PPh₃)₂ was supported on the surface of silica gel, cis-RhCl(CO) (PPh₃)₂ species was detected via the splitting of the CO infra red stretching band of trans-RhCI (CO)(PPh₃)₂. With other supports, same phenomenon was observed but with the different pattern of intensities of the splitted CO stretching bands. RhH(CO)(PPh₃)₃ was easily decarbonylated, after interacting with the surface of silica gel, γ-alumina, and titania. However, [RhCl(CO)₂]₂ was decarbonylated on the surface of inorganic oxides mentioned above and most of supported [RhCl(CO)₂]₂ converted to a stable surface carbonyl species [M-OH-RhCI(CO)₂; M = Si, Al, Ti]. Diffuse reflectance infrared spectroscopy (DRS) was used to study the interactions of 5 wt % RhCl(CO)(PPh₃)₂ supported on silica gel with H₂, CO and/or propylene at various temperatures. The result indicated that the surface intermediates formed from the interaction of RhCl(CO)(PPh₃)₂ with CO, H₂ and C₃H₆ were not identical to the corresponding liquid-phase intermediates of RhCl(CO)(PPh₃)₂ in the presence of solvent.     

The oxidative inducation test applied to medical PVC and other polymers

We have examined the applicability of this simple and effective test to polymer systems widely used in the medical industry. First, it was found that not every polymer examined exhibited a distinct onset of autocatalytic oxidation detectable by DSC. However, for cases where distinct onsets are found, powerful insights can be obtained. These included activation energy of the degradation, thermal oxidative shelf life prediction, and correlation, with product performances. Actual examples are presented to illustrate the utility of the test.     

Thermal error analysis for a CNC lathe feed drive system

The development of high-speed feed drive systems has been a major issue in the machine tool industry for the past few decades. The resulting reduction in the time needed for tool changes and the rapid travel time can enhance productivity. However, a high-speed feed drive system naturally generates more heat and resultant thermal expansion, which adversely affects the accuracy of machined parts. This paper divides the feed drive system into two parts: the ball screw and the guide way. The thermal behavior model for each part is developed separately, in order to estimate the position errors of the feed drive system caused by thermal expansion. The modified lumped capacitance method (MLCM) and genius education algorithm (GEA) are used to analyse the linear positioning error of the ball screw. Thermal deformation of the guide way affects straightness and introduces angular errors, as well as affecting linear positioning. The finite element method is used to estimate the thermal behavior of the guide way. The effectiveness of the proposed models is verified through experiments using a laser interferometer.     

Sub-30 nm gate template fabrication for nanoimprint lithography using spacer patterning technology

In this study, we present a spacer patterning technology for sub-30 nm gate template which is used for nano-scale MOSFETs fabrication. A spacer patterning technology using a poly-silicon micro-feature and a chemical vapor deposition (CVD) SiO2 spacer has been developed, and the sub-30 nm structures by conventional dry etching and chemical mechanical polishing are demonstrated. The minimum-sized features are defined not by the photolithography but by the CVD film thickness. Therefore, this technology yields a large-area template with critical dimension of minimum-sized features much smaller than that achieved by optical lithography.     

Radio frequency source power-induced ion energy impact on SiN films deposited using a room temperature SiH4-N2 plasma

Using a SiH4-N2 plasma, silicon nitride films were deposited at room temperature. The impact of source power ranging from 500 to 900 W and ion energy are investigated. The film properties examined include a deposition rate, a refractive index, and a surface roughness. Ion energy diagnostics was conducted to explore the relationships between ion energy and film properties. A variation in ion energy with source power was quite complex. By contrast, a decrease in ion energy flux was observed for a decrease in the source power. An increase in the deposition rate with the decrease in source power was attributed to enhanced ion energy. The refractive index strongly correlated with low ion energy flux. A decrease in surface roughness in the range of 500-700 W was related to larger ion energy. The deposition rate, refractive index, and surface roughness were varied in the range of 0.27-0.35 nm/sec, 1.690-1.739, and 6.7-52.5 nm, respectively.     

Completing the color palette with spray-processable polymer electrochromics

The field of electrochromic polymers has now reached an important milestone with the availability of a yellow to fully transmissive, cathodically coloring, solution-processable electroactive polymer. This is in addition to previously published electrochromic polymers that have neutral state colors that span from orange, red, magenta, blue, cyan, green, and black, that also attain highly transmissive states upon switching. With this, the full color palette is now complete allowing the largest variety of colors for transmissive and reflective electrochromic display applications. Here, we report on how we have been able to obtain this full color palette through synthetic modifications and color tuning utilizing electron rich and donor-acceptor repeat units, electron-donating substituents, and steric interactions with our 3,4-alkylenedioxythiophene family of polymers. Additionally, using solubilizing pendant groups for both organic and aqueous compatibility, we have been able to create this color palette with fully solution processable materials, paving the way for materials patterning, printing, and incorporation into devices for display and window applications.