Runner sizing and weld line positioning for plastics injection moulding with multiple gates

Weld line and warping are two critical defects for injection-moulded part. If weld lines are unavoidable due to multiple gates in a moulding, they should be positioned in the non-critical region. Instead of using flow leaders and deflectors to control the locations of the weld lines, this paper presents an approach to specify the locations of the weld lines by sizing the runners in a multi-gated injection moulding with the optimum gate locations. The methodology consists of three steps: partitioning the moulding into sub-mouldings based on the specified weld line location, determining the optimum gate location in each sub-moulding by minimizing the injection pressure and repositioning the weld lines to the desired locations by varying the runner sizes. Two examples are used to illustrate the approach.     

Trisomy 5 in two cases of acute monocytic leukemia with hyperdiploid clones

Although numerical chromosomal aberrations are commonly seen in acute myeloid leukemia (AML), trisomy 5 (+ 5) is very rarely detected. We report two patients, both of whom suffered from acute monocytic leukemia, in which + 5 was found in hyperdiploid clones. A review of the English literature shows 17 additional cases of AML with + 5 in at least one of the abnormal clones, making a total of 19 such cases including ours. Trisomy 5 has been reported in all FAB subtypes of AML except acute promyelocytic leukemia. In the 19 cases identified in this report, + 5 was found in association with other numerical changes (four cases), structural changes (five cases) or both (eight cases). Trisomy 5 as a sole karyotypic abnormality was exceedingly rare (two cases). Its biologic and prognostic significance remains to be determined.     

等效介质理论用于单向纤维增强复合材料弹性性能的数值计算

本文把一套等效介质理论简化成为一数值方法,用于横观各向同性组分构成的单向纤维增强复合材料弹性性能的计算。我们计算了几个单向纤维增强的系统并把计算值与实验值作出比较,得到很好的符合。     

Backscattering enhancement and clustering effects of randomlydistributed dielectric cylinders overlying a dielectric half space basedon Monte-Carlo simulations

Backscattering enhancement can exist in volume-surface interactions where a double bounce can arise from one volume scattering and one surface scattering. An important quantity to be determined in backscattering enhancement is the angular width. The authors study backscattering enhancement of the volume-surface interaction by performing Monte-Carlo simulations of scattering by vertical dielectric cylinders overlying a dielectric half space using the Foldy-Lax multiple-scattering equations. The results indicate that the angular width of backscattering enhancement for a scattering layer with a small optical thickness is of the order of the wavelength divided by the layer thickness giving an appreciable angular width of the order of 10-30 degrees that can be important for remote sensing applications. The effects of clustering of scatterers leading to collective scattering and absorption effects are also studied     

Classification decision model for a Hong Kong clothing manufacturing plant locations using an artificial neural network

Clothing manufacturers’ direct investment and joint ventures in developing regions have seen to grow rapidly in the past few decades. Manufacturers face difficulties during the decision-making process in the selection of a plant location due to vague and subjective considerations. Selecting a plant location relies mostly on subjective intuition and assessment as variables to be considered in the decision making process. But these variables cannot always be represented in terms of objective value, such as country risk and community facilities. Though several optimization techniques have been developed to assist decision makers in searching for the optimal sites, it is difficult to rank the sites which display a small difference of scores. Classification is thus more reasonable and realistic. This paper investigates two recent types of classification techniques, namely unsupervised and supervised artificial neural networks, on the site selection problem of clothing manufacturing plants. The limitations of adaptive resonance theory in unsupervised artificial neural networks will be demonstrated. A comparison of the performance of the three types of supervised artificial neural networks – including back propagation, learning vector quantization and probabilistic neural network – is used and the proposed classification decision model will be presented. The experimental results indicate that the supervised artificial neural network is a proven and effective classifier in which a probabilistic neural network performs better than the others in this site selection problem.     

Electrically controllable all-fiber PMD emulator using a compact array of thin-film microheaters

An electrically controllable, all-fiber polarization-mode dispersion (PMD) emulator is constructed using thin-film microheaters to temperature tune the birefringence of 30 PM-fiber sections spliced at 45/spl deg/ angles. Compact packaging is achieved by mounting the fiber heaters onto an array of silicon V-grooves. The advantages of this electrically tunable emulator design are low loss, negligible PDL, simple construction, no internal reflections, and no moving parts.     

Penetration of intravesical doxorubicin in human bladders

The bladder wall penetration kinetics of intravesical doxorubicin were examined in radical cystectomy patients, to provide insight into drug concentrations at target tumor sites. The dosing solution (40 mg/20 ml) was instilled just prior to the start of surgery and maintained for 60-115 min until just prior to bladder excision. The data showed considerable inter-patient variability in the peak plasma concentration (24-fold), urine concentration (7- fold), and tissue concentration (28-fold). The urine concentration at the time of tissue harvest was about 17% of the concentration in the dosing solution. This was due to the dilution by post-catheterization residual urine and urine produced during treatment. The doxorubicin concentration dropped by 32-fold across the urothelium, and declined semi-logarithmically with respect to depth in the capillary-perfused tissues beneath the urothelium with a 50% decrease over about 500 micromole. In three of six patients from whom tumor tissue was obtained, the doxorubicin concentration was higher than the adjacent non-tumor-bearing tissues of comparable tissue depth, whereas the reverse was seen in the remaining three tumors. The plasma concentrations were 0.02, 0.03, 0.05, 0.27, and 0.69% of the concentrations in the tumors, urothelium, lamina propria, superficial and deep muscle layers, respectively. These data indicate: (a) a considerable intra- and inter-patient variability in bladder tissue concentrations, in part due to the variability in the urine concentration; (b) the urothelium is an effective barrier to doxorubicin penetration; and (c) a targeting advantage of intravesical therapy for the treatment of superficial bladder cancer yielding superficial bladder tissue concentrations at least 2000-fold higher than in the systemic circulation. A comparison of the data of doxorubicin with our previously published data on mitomycin C shows similar bladder tissue pharmacokinetics for the two drugs, suggesting that there is no pharmacokinetic preference for either drug.     

Effects of group size and procedural influence on consensual judgments of quantity: The examples of damage awards and mock civil juries.

Six-person mock civil juries awarded significantly larger amounts for damages than did 12-person juries, and individuals preferred even larger average awards. A reversal of the "deep-pockets bias" observed earlier, an explanation involving temporal fluctuation in normative standards, during the time interval between the studies, was supported by independent data showing temporal trends in actual civil trial awards. A computational model of consensus that assumed a strong majority of those members with the most similar (closest) personal preferences decided on the median of their preferences accurately predicted award magnitude. Computer simulations explored the effects of critical faction size (majority, etc.) and location within the group, features that might in turn depend on task environment, cultural dynamics, and social context. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Methane dehydrogenation and aromatization over 4 wt% Mn/HZSM-5 in the absence of an oxidant

Methane dehydrogenation and aromatization over 4 wt% Mn/HZSM-5 in the absence of an oxidant (GHSV = 1600 mL h⁻¹ g⁻¹) was investigated. Mn/HZSM-5 was prepared by impregnation of HZSM-5 with manganese acetate tetrahydrate solution; Mn₃O₄ formed was the precursor of active phase for methane activation. The induction period over Mn/HZSM-5 catalyst before aromatic products appear was long at 700 °C. This period shortened with a rise of the reaction temperature to 800 °C. XPS and TPO results showed that the partly carburized or carburized Mn species formed are probably responsible for methane activation.