Surface profile measurement in white-light scanning interferometry using a three-chip color CCD

White-light scanning interferometry (WLSI) is a useful technique to measure surface profile when a test object contains discontinuous structures or microstructures. A black and white CCD camera is usually utilized to capture interferograms, and a series of corresponding algorithms is used to achieve the profile measurement. However, the color information in the interferograms is lost. A novel profile measurement method that uses phase information in different color channels (red-green-blue) of an interferogram obtained using a three-chip color CCD in WLSI is proposed. The phase values are extracted by a windowed Fourier transform algorithm. Simulation and experimental results are presented to demonstrate the validity of the proposed method.     

Structural, optical, magnetic and electrical properties of Zn1−x Co x O thin films

Despite a considerable effort aiming at elucidating the nature of ferromagnetism in ZnO-based magnetic semiconductor, its origin still remains debatable. Although the observation of above room temperature ferromagnetism has been reported frequently in the literature by magnetometry measurement, so far there has been no report on correlated ferromagnetism in magnetic, optical and electrical measurements. In this paper, we investigate systematically the structural, optical, magnetic and electrical properties of Zn_1−x Co _x O:Al thin films prepared by sputtering with x ranging from 0 to 0.33. We show that correlated ferromagnetism is present only in samples with x > 0.25. In contrast, samples with x < 0.2 exhibit weak ferromagnetism only in magnetometry measurement which is absent in optical and electrical measurements. We demonstrate, by systematic electrical transport studies that carrier localization indeed occurs below 20–50 K for samples with x < 0.2; however, this does not lead to the formation of ferromagnetic phase in these samples with an electron concentration in the range of 6 × 10¹⁹ cm⁻³ ∼1 × 10²⁰ cm⁻³. Detailed structural and optical transmission spectroscopy analyses revealed that the anomalous Hall effect observed in samples with x > 0.25 is due to the formation of secondary phases and Co clusters.     

Pentadiagonal alternating-direction-implicit finite-difference time-domain method for two-dimensional Schrödinger equation

In this paper, we have proposed a pentadiagonal alternating-direction-implicit (Penta-ADI) finite-difference time-domain (FDTD) method for the two-dimensional Schrödinger equation. Through the separation of complex wave function into real and imaginary parts, a pentadiagonal system of equations for the ADI method is obtained, which results in our Penta-ADI method. The Penta-ADI method is further simplified into pentadiagonal fundamental ADI (Penta-FADI) method, which has matrix-operator-free right-hand-sides (RHS), leading to the simplest and most concise update equations. As the Penta-FADI method involves five stencils in the left-hand-sides (LHS) of the pentadiagonal update equations, special treatments that are required for the implementation of the Dirichlet’s boundary conditions will be discussed. Using the Penta-FADI method, a significantly higher efficiency gain can be achieved over the conventional Tri-ADI method, which involves a tridiagonal system of equations.     

Formation of bed agglomeration in a fluidized multi-waste incinerator

A case study was carried out to investigate the bed agglomeration observed in a fluidized bed incinerator when burning blends of three wastes (carbon soot, biosludge and fuel oil). Several instrumental approaches were employed (i.e. XRF, SEM, XRD, and ICP-AES) to identify the bed materials (fresh sand and degrader sand) and clinkers formed in the full-scale incinerator tests. Several elements (V, Al, S, Na, Fe, Ni, P, and Cl), which normally are associated with the formation of low melting point compounds, were found in the waste blends at high content levels. The clinker bridges were identified to be associated with Al, Fe, V, K, Na, S, Ni, and Si elements.The effects of temperature and blending ratio were investigated in a muffle furnace. Carbon soot is believed to be more susceptible to the clinker formation than the other two fuels. Thermodynamic multi-phase multi-component equilibrium calculations predict that the main low melting point species could be Al₂(SO₄)₃, Fe₂(SO₄)₃, Na₂SO₄, NaCl, Na₂SiO₃ and V₂O₅. This information is useful to understand the chemistry of clinker formation. Also, it helps to develop methods for the control and possible elimination of the agglomeration problem for the design fuels.     

Outcome of obstructive uropathy after pelvic irradiation in patients with carcinoma of the uterine cervix

A prospective, randomized study was performed to assess the effectiveness of postoperative closed suction drainage. One hundred and twelve consecutive procedures involving autologous iliac-crest bone graft were performed, from December 29, 1992, to July 1, 1993, following a traumatic injury of the spine in 108 patients. Sixty of the sites from which the bone graft had been obtained were drained with a single large Hemovac device. The drains were maintained for two to five days postoperatively. The remaining fifty-two incisions were closed without a drainage device. All patients were evaluated clinically for problems with wound-healing. The incisions were considered to be healed when they had been asymptomatic for one year. Of eleven patients who had problems with wound-healing, six had been managed with a drain and five had not. The findings of this study do not support the routine use of drainage at the donor sites of iliac-crest bone grafts.     

Media-Induced Hydraulic Behavior and Performance of Upflow Biofilters

Laboratory studies were conducted to assess the influence of media-related factors such as porosity, specific surface, and pore size on hydraulic behavior and performance of upflow anaerobic biofilters (ABFs). Three 15-L upflow biofilters, each packed with different support media, were subject to identical synthetic protein-carbohydrate substrate with chemical oxygen demand (COD) concentrations ranging from 2,500 to 10,000 mg∕L, and hydraulic retention times from 15 to 30 hours, corresponding to organic loading rates (OLRs) varying from 2 to 16 g COD∕L∕d. Tracer studies were carried out to characterize hydraulic behavior of the biofilters containing media with and without biomass, designated as dirty-bed and clean-bed, respectively. The results indicate that hydraulic flow regimes in all biofilters were characterized by a plug-flow pattern with a large extent of dispersion under clean-bed conditions. The tracer response curve under dirty-bed conditions operating at an OLR of 16 g COD∕L∕d reflects more closely the response of a mixed-flow reactor than that of a plug-flow unit, which suggests that there is significant short-circuiting in the ABFs. Waste treatment performance indicates that the biofilter associated with media of the largest pore size and porosity consistently demonstrated the highest COD removal from 96% to 73% at loadings varying from 2 to 16 g COD∕L∕d. The same reactor exhibited the lowest magnitude of dispersion along with minimum dead space within the bed from the tracer analysis. This implies that the use of support media with larger pore size and porosity may reduce the extent of short-circuiting, leading to better waste treatment performance. Increasing the media specific surface at the expense of media porosity may result in lower treatment performance in upflow anaerobic biofilters.     

Group B Streptococcal septicaemia/meningitis in neonates in a Singapore teaching hospital

Several studies have indicated that frequent allelic losses in some specific chromosomal regions occur during colorectal cancer (CRC) progression. To clarify the correlation between such allelic losses and metastatic potential, the allelotype of lymph node-positive early CRCs, which are small but extremely malignant cancers consisting of metastatically competent cells, were investigated. Nineteen paraffin-embedded specimens of early CRC (pT1 tumors according to TNM classification) with positive lymph nodes were collected. The tumor tissues were examined for loss of heterozygosity (LOH), using microsatellite markers on chromosomes 1p34-36, 8p21-22, 14q32, 18q21 and 22q12-13. The relationship between p53 protein expression and the metastatic status was also investigated by immunohistochemical staining. A group of 20 early CRCs with negative lymph nodes having a similar distribution of macroscopic appearance were used as controls. Among the 19 node-positive tumors, LOH at 8p21-22 and 18q21 was detected in 11 cases (57.9%) and 17 cases (89.4%), respectively. Allelic losses within these 2 regions in node-positive tumors were significantly more frequent than that in node-negative ones (p < 0.01). No significant correlation was found between LOH at 1p34-36, 14q32 or 22q12-13 and lymph node metastasis. p53 protein expression was not significantly associated with lymph node metastasis. Our results suggest that putative tumor suppressor genes, which may be involved in the metastatic process of CRC, are located on chromosomes 8p21-22 and 18q21. Allelic losses in these regions are possible risk factors for lymph node metastasis of early CRC.     

Many strings attached: from conventional to robotic marionette manipulation

This paper introduces the evolution of traditional marionette design and manipulation skills from an engineering perspective and describes a novel system developed in Nanyang Technological University, called Robotic Marionette Systems (ROMS). Through the development of ROMS and the marionette motion generation methods, the possibility of infusing modern robotic and mechatronic technology into the traditional art form of marionette performance is explored while, at the same time, evoking and stimulating public interests in this art form.     

Racial variation of factor VII activity and antigen levels and their correlates in healthy Chinese and Indians at low and high risk for coronary artery disease

We examined the genotypes of ALDH2, ADH2, ADH3 and P-4502E1 loci of alcoholics and nonalcoholics. Also we compared the frequencies of the homozygous ALDH2*1/1 genotype and heterozygous ALDH2*1/2 genotypes in alcoholics. Our study reported differences in the allelic frequencies of ALDH2, ADH2 and ADH3 loci between alcoholics and nonalcoholics. For alcoholics, it was indicated that ADH2 and ADH3 plays an important role for alcoholism. For genotypes of P-4502E1, no significant difference was observed between alcoholics and nonalcoholics. Alcoholics with the heterozygous ALDH2*1/2 genotype had significantly higher frequency of the ADH2*1 than that of alcoholics with ALDH2*1/1 genotype. Concerning the alcoholics with the heterozygous ALDH2*1/2 genotype, we assumed that ADH2*1 plays a role for the development of alcoholism.     

Effects of cationic polymer on start‐up and granulation in upflow anaerobic sludge blanket reactors

The upflow anaerobic sludge blanket (UASB) has been used successfully to treat a variety of industrial wastewaters. It offers a high degree of organics removal, low sludge production and low energy consumption, along with energy production in the form of biogas. However, two major drawbacks are its long start‐up period and deficiency of active biogranules for proper functioning of the process. In this study, the influence of a coagulant polymer on start‐up, sludge granulation and the associated reactor performance was evaluated in four laboratory‐scale UASB reactors. A control reactor (R1) was operated without added polymer, while the other three reactors, designated R2, R3 and R4, were operated with polymer concentrations of 5 mg dm^?3, 10 mg dm^?3 and 20 mg dm^?3, respectively. Adding the polymer at a concentration of 20 mg dm^?3 markedly reduced the start‐up time. The time required to reach stable treatment at an organic loading rate (OLR) of 4.8 g COD dm^?3 d^?1 was reduced by more than 36% (R4) as compared with both R1 and R3, and by 46% as compared with R2. R4 was able to handle an OLR of 16 g COD dm^?3 d^?1 after 93 days of operation, while R1, R2 and R3 achieved the same loading rate only after 116, 116 and 109 days respectively. Compared with the control reactor, the start‐up time of R4 was shortened by about 20% at this OLR. Granule characterization indicated that the granules developed in R4 with 20 mg dm^?3 polymer exhibited the best settleability and methanogenic activity at all OLRs. The organic loading capacities of the reactors were also increased by the addition of polymer. The maximum organic loading of the control reactor (R1) without added polymer was 19.2 g COD dm^?3 d^?1, while the three polymer‐assisted reactors attained a marked increase in organic loading of 25.6 g COD dm^?3 d^?1. Adding the cationic polymer could result in shortening of start‐up time and enhancement of granulation, which may in turn lead to improvement in the efficiency of organics removal and loading capacity of the UASB system. Copyright © 2004 Society of Chemical Industry