Search

This study investigates the urban-rural and sex differences in the increased risks of the ten most common cancers in China related to high PM2.5 concentration in the southeastern side of Hu line. Pearson correlation coefficient is estimated to reveal how the cancers closely associated with PM2.5 long-term exposure. Then linear regression is conducted to evaluate sex- and area-specific increased risks of those cancers from high level PM2.5 long-term exposure. The major finding is with the increase of every 10 μg/m3 of annual mean PM2.5 concentration, the increase of relative risks for lung cancer incidence and mortality are 15% and 23% for males, and 22% and 24% for females in rural area. For urban area, the increase of relative risk for ovarian cancer incidence is 9% for females, while that for prostatic cancer increases 17% for males. For leukemia, the increase of relative risks for incidence and mortality are 22% and 19% for females in rural area, while in urban area the increase of relative risk for mortality is 9% for males and for incidence is 6% for females. It is also found that with increased PM2.5 exposure, the risks for ovarian and prostatic cancer rise significantly in urban area, while risks for lung cancer and leukemia rise significantly in rural area. The results demonstrate the higher risks for lung cancer and leukemia with increased PM2.5 exposure are more significant for female. This study also suggests that the carcinogenic effects of PM2.5 have obvious sex and urban-rural differences.

The Djumbodis™ dissection system was introduced as an alternative to aortic arch replacement in acute type A aortic dissection involving the arch. In our own experience, some patients with Djumbodis implantation developed distal aortic arch and descending aortic aneurysm during subsequent follow-up and required additional interventions. However, as there is a high incidence of fracture associated with the Djumbodis system, further endovascular interventions are not feasible. We report a case of successful open descending aortic replacement in a patient with a fractured Djumbodis stent system.

Recently, electrical vehicle (EV) charger demand has been grown rapidly due to electrical vehicle development, so we designed a full SiC power module for EV charger system. The power consumption and thermal performance of EV charger module were evaluated by simulation software. Besides, we did the thermal resistance measurement of full SiC module and calibrated the Rjc (junction-case) .The simulation results show that we can reduce the size of heatsink because of higher system efficiency caused by full SiC power module. The advantage of using SiC chip in EV charger power module lose less power than silicon power module because of SiC chip’s electrical characteristic.

The paper introduces a 600V/30A intelligent power module packaging structure which uses the thermal interface material (TIM) to be the insulation layer. This layer has the high thermal dissipation capability that helps to transfer the heat generated from power chips. The IPM are utilized for home applications such as air-conditioning, refrigerators, and washing machines etc. By fast switching the power chips to control the motor drive and save the energy. Compared to conventional direct bonded copper (DBC) type IPM, the developed IPM has the lighter packaging structure, simple fabrication process, and lower thermal conduction path that means a good performance will show up when using it for motor drive. Moreover, the TIM type IPM has passed the long term reliability test including thermal cycling test (TCT), highly-accelerated temperature and humidity stress test (HAST), and high temperature storage test (HTS).

In 2017 ECTC, we demonstrated an on-chip thick copper "Air-core" inductor integrated with proposed WLCSP-like packaging solution. This year, the spotlight of the upgraded on-chip inductor package is two-fold. The first is a planar magnetic (MAG) film with high permeability is integrated into the inductor. The second is the thickness of the Cu redistribution layer (RDL) becomes 3~4 fold thicker than that used in typical WLCSP. These two paths are used for achieving superior inductance as well as electrical performance. The integrity of "Metal Contact Via" plays an important role on the realization of the on-chip MAG thick Cu inductor package. Two key process issues relating to metal contact at via area will be disclosed and focused for the first time. Two novel concepts ("Patterned Metal-Cut Protection Layer (PMCPL)" & "Multilayer-Etching Stop Layer (M-ESL))" are introduced for the via process improvement. The issues, the fundamental root cause, and the improvement actions will be discussed step-by-step in this paper. In short, without such two imperative improvement approaches as just mentioned, not only will the device function open (fail), but the excellent electrical performance will not be realized as well. At last, compared to the air-core thick copper inductor package reported last year, the results show that the inductance density can boost up 9-fold and the direct resistance (Rdc) significantly reduces 2-fold.

A fine-pitch dielectric layer was introduced in hybrid fan-out packaging structure. A hybrid fan-out structure could enable higher routing density and higher power consumption electronics. The siloxane material dielectric layer with breakdown voltage over 400kV/mm and leakage current less than 10−12A at 200kV/mm was fabricated on silicon wafer. Moreover, Line/Space 2/2μm microvias resolution was achieved with taper angle of 70.8°. The adhesion between trace and dielectric was evaluated by high temp. / high humidity test. The possibility to exhibit 2/2μm fine-pitch hybrid fanout packaging was demonstrated in package level.

The purpose of this study was to determine factors associated with self-perceived body image in female patients with head and neck cancer (HNC), and factors associated with healthcare professional's rating of disfigurement, as well as the correlation between patient and observer ratings. This cross-sectional study recruited 105 women with HNC at a large medical centre. Measures of facial disfigurement and body image, as well as demographic and clinical characteristics, were collected. Multivariate multiple linear regression modelling was used to identify factors associated with healthcare professional's rating of disfigurement and patient self-perceived body image. Disfigurement ratings by healthcare professionals were positively associated with patient self-perceived body image. Medical treatment, cancer stage, radiation dose and cancer site were significantly associated with disfigurement. Medical treatment was an important predictor of perceived body image. These findings indicate a moderate prevalence of disfigurement among women with HNCs. Patients with more disfigurement were more likely to have dissatisfaction with their body image. Nursing professionals need to carefully assess the appearance of women with HNC. Camouflage interventions can be used to help appropriately cope with the disfigurement, and to achieve improved satisfaction with their body image.

The feasibility of a 3D IC integration SiP has been demonstrated in this investigation. The heart of this SiP is a TSV (through-silicon via) interposer with RDL (redistribution layer) on both sides, IPD (integrated passive devices) and SS (stress sensors). This interposer is used to support (with microbumps) a stack of four memory chips with TSVs, one thermal chip with heater and one mechanical chip with SS, and then overmolded on its top side for pick and place purposes. The interposer’s bottom-side is attached to an organic substrate (with ordinary lead-free solder bumps), which is lead-free solder-balled on a PCB (printed circuit board). Key enabling technologies such as TSV etching, chemical mechanical polishing (CMP), thin-wafer handling, thermal management, and microbumping, assembly and reliability are highlighted.

In this study, three types of adaptive neuro fuzzy inference system (ANFIS) and artificial neural network (ANN) were employed to predict suspended solids (SS eff ) and chemical oxygen demand (COD eff ) in the effluent from a hospital wastewater treatment plant. The results indicated that ANFIS statistically outperforms ANN in terms of effluent prediction. The minimum mean absolute percentage errors of 11.99% and 12.75% for SS eff and COD eff could be achieved using ANFIS. The maximum values of correlation coefficient for SS eff and COD eff were 0.75 and 0.92, respectively. The minimum mean square errors of 0.17 and 19.58, and the minimum root mean square errors of 0.41 and 4.42 for SS eff and COD eff could also be achieved. ANFIS's architecture consists of both ANN and fuzzy logic including linguistic expression of membership functions and if–then rules, so it can overcome the limitations of traditional neural network and increase the prediction performance.

Human papillomavirus (HPV) infections are deemed to play a role in the pathogenesis of oral cavity cancer (OCC). However, their exact prevalence and clinical significance remain unclear. Herein, we investigated the prevalence and prognostic value of HPV infections in a large sample of Taiwanese OCC patients. This study was designed as a retrospective cohort study. Between 2004 and 2011, we identified 1002 consecutive patients with newly diagnosed OCC who were scheduled for standard treatment. HPV genotyping was performed in tumor specimens using polymerase chain reaction-based HPV blots. To investigate the temporal trends of HPV infections and their impact on 5-year overall survival (OS), patients were divided into 2 cohorts according to calendar periods: “2004 cohort” (2004–2007; n = 466) and “2008 cohort” (2008–2011; n = 536). Univariate and multivariate Cox regression models were also used to identify the independent predictors of OS in the 2 cohorts. A weighted risk score was assigned to each factor based on the range of their corresponding hazard ratios and validated in both cohorts using the c-statistic. The overall prevalence of HPV infections was 19%, with a trend toward decreasing rates from 2004 to 2011. In patients without risky oral habits, the 5-year OS rate of HPV-positive patients was significantly lower than that of HPV-negative cases (49% vs 80%; P = 0.021). In the 2004 cohort, multivariate analysis identified HPV16, pathological T3/T4, pathological N1/N2, and extracapsular spread as independent adverse prognostic factors for OS. In the 2008 cohort, pathological N1/N2, pathological stage III/IV, and histological tumor depth >8 mm were identified as independent adverse prognostic factors. Using a weighted grading system incorporating HPV16 infection, we devised a prognostic index that identified 4 distinct risk categories with 5-year OS rates ranging from 25% to 89% (c-statistic = 0.76) in the 2004 cohort. The validity of the index was internally confirmed in the 2008 cohort (c-statistic = 0.71). We conclude that HPV infections are common in Taiwanese OCC patients and predict 5-year OS. If independently validated, our composite prognostic score comprising HPV16 infection may be useful for allocating OCC patients to risk-adapted therapies.

Purpose: To report on fluoroscopically guided percutaneous gastrostomy (FPG) using a modified gastropexy technique with the insertion of a large‐bore balloon‐retained gastrostomy catheter in patients with head and neck tumors. Material and Methods: Thirty‐four patients with head and neck tumors underwent a modified gastropexy with two T‐fasteners followed by the insertion of a 14‐F balloon‐retained catheter through a peel‐away introducer. The success rate and the complications of the procedures were evaluated at 14 days, 30 days, and 60 days. The complications were classified as: major complications that necessitated intensive and/or surgical treatment; minor complications that could be treated conservatively; and tube‐related complications manageable by tube exchange. Results: FPG was technically successful in all cases. There were no major complications, two minor complications where superficial stoma infection was controlled by antibiotics, three minor tube‐related complications, all three easily managed by catheter replacement via the original tract. Conclusion: FPG with insertion of a large‐bore balloon‐retained catheter using a modified gastropexy technique is a safe and effective method that creates a feeding access for patients with head and neck tumors and esophageal obstruction. Minor complications can be managed conservatively. FPG may be a good alternative to surgical or percutaneous endoscopic gastrostomy.

The frequency dependence of scattering by geophysical media at microwave frequencies is an important topic because multifrequency measurements are used in remote sensing applications. In this paper, we study rigorously the frequency dependence of scattering by dense media using Monte Carlo simulations of the three-dimensional solutions of Maxwell's equations. The particle positions are generated by deposition and bonding techniques. The extinction, scattering, and absorption properties of dense media are calculated for dense media of sticky and nonsticky particles. Numerical solutions of Maxwell's equations indicate that the frequency dependence of densely packed sticky small particles are much weaker than that of independent scattering. Numerical results are illustrated using parameters of snow in microwave remote sensing. Comparisons are made with extinction measurements as a function of frequency.

The ultra-high vacuum chemical vapor deposition (UHVCVD) system can deposit poly-Si film without any laser or furnace annealing. The uniformity of threshold voltage and mobility is superior to that deposited by low-pressure chemical vapor deposition (LPCVD) system. However, due to the deposition in polycrystalline phase for UHVCVD, the film surface is rough and results in low field effect mobility compared to that obtained by LPCVD using disilane (Si2H6) in amorphous phase followed by solid phase crystallization (SPC). The on–off current ratio for UHVCVD deposited poly-Si thin film transistors (TFTs) is approximately one order smaller, however, the leakage current for LPCVD SPC TFTs is higher. In this experiment, NH3 was introduced to both of the two samples to improve the device performance. It can be shown that improvements on device characteristics are more significant for UHVCVD deposited poly-Si TFTs, e.g. threshold voltage decreased dramatically and the on–off current ratio improved by two orders of magnitude. r 2002 Elsevier Science Ltd. All rights reserved.

The frequency dependence of extinction and scattering by geophysical medium at microwave frequencies is an important scattering topic because multifrequency measurements are used in remote sensing applications. Classical independent scattering theory states that if the particles are small, scattering is proportional to the fourth power in three-dimensional (3D) scattering and the third power in two-dimensional (2D) scattering. In this paper, the authors present Monte Carlo simulation results of dense media scattering. The dense media consists of densely packed small particles. Solutions are based on rigorous methods of generating dense media and subsequent numerical solutions of Maxwell's equation. Numerical simulations indicate that the frequency dependence of densely packed sticky particles is weaker than independent scattering.

During parallel testing of integrated circuits (ICs), many are incorrectly rejected because of faulty sockets or test hardware system failure associated with socket location. A two-stage procedure for monitoring socket locations is proposed. Stage one i..

Dense media radiative transfer (DMRT) equations based on quasicrystalline approximation (QCA) for densely distributed moderate size particles are developed. We first compute the effective propagation constant and coherent transmission into a dense medium on the basis of the generalized Lorentz-Lorenz law and the generalized Ewald-Oseen extinction theorem. The absorption coefficient of the dense media is then calculated. The distorted Born approximation is next applied to a thin layer to determine the bistatic scattering coefficients and the scattering coefficient. The phase matrix in DMRT is then obtained as bistatic scattering coefficient per unit volume. The model is applied to multiple sizes and for sticky particles. Numerical results are illustrated for extinction and brightness temperatures in passive remote sensing using typical parameters in snow terrain. The QCA-based DMRT is also used to compare with satellite Special Sensor Microwave Imager (SSM/I) brightness temperatures for four channels at 19 and 37 GHz with vertical and horizontal polarizations and for two snow seasons. It shows reasonable agreement to snow depth of 1 m.

For this study, consideration is given to the role crystal orientation plays in scattering and absorbing microwave radiation. A discrete dipole scattering model is used to measure the passive microwave radiation at two polarizations (horizontal and vertical), scattered by snow crystals oriented in random and nonrandom positions and having various sizes (ranging from 1 /spl mu/m to 10000 /spl mu/m in radius) and shapes (including spheres, cylinders, hexagons). The model results demonstrate that for the crystal sizes typically found in a snowpack, crystal orientation is insignificant compared to crystal size in terms of scattering microwave energy in the 8100 /spl mu/m (37 GHz) region of the spectrum. Therefore, the assumption used in radiative transfer approaches, where snow crystals are modeled as randomly oriented spheres, is adequate to account for the transfer of microwave en energy emanating from the ground and passing through a snowpack.

The conventional Shewhart X chart is developed based on the assumption that the within-sample variation is due to the inherent process variation, and any significant variation between samples is attributed to the existence of assignable causes. In the manufacturing industry there are processes where there is variation between samples due to the inherent process variation. A straightforward application of the conventional Shewhart X chart would thus result in more frequent false alarms. The problems associated with various Shewhart X charts in monitoring such a process are discussed using a real data set from an integrated circuit (IC) assembly process. A Shewhart X chart with modified limits is adapted for such a process. In addition to the usual ability to signal for assignable causes, the X chart with modified limits is also developed as a tool to signal the need for adjustment of controllable process variables for improving the process capability. Practical application of this chart in monitoring an IC assembly process is discussed. Copyright © 1999 John Wiley & Sons, Ltd.

Singapore's meetings, incentive, convention and exhibition industry (MICE) attracts over 4,000 events and over 400,000 foreign participants every year. Since 1982, Singapore has been the top convention destination in Asia and today ranks among the top ten in the world. An assessment of Singapore MICE attractiveness shows that while the country has many strengths, particularly infrastructure and management, it has a number of weaknesses, as well, including limited entertainment and cultural attractions. Further analysis shows that much of Singapore's success has been based on regional meetings, rather than truly global events. As regional competition heats up, Singapore will need to better develop the global market. To do this Singapore is attempting to leverage its well developed transportation, hospitality and human resources, along with its role as a regional and global economic center.

A modified geometric model is proposed for fitting data generated from a process where most of the samples are conforming and occasional samples are non-conforming. These near-zero-defect processes are classified as processes subjected to random shocks. A graphical comparison of the goodness of fit of industrial process data using modified geometric and modified Poisson models is performed. The geometric model is found to provide a better fit than the Poisson model. Based on the modified geometric model, a charting scheme consisting of two charts is developed to monitor a process subjected to random shocks. A cumulative count of conforming chart is used to monitor the frequency of random shocks and a geometric chart is used to monitor the count of non-conformities. The geometric chart performs better than the Poisson chart in terms of false alarm rate. The performance of the scheme is also evaluated.

The objective of this study was to test the hypothesis that neurodevelopmental outcome would differ between two groups of small-for-gestational age infants born at term showing different in utero growth characteristics during the third trimester. The design was a prospective cohort study done at a tertiary referral centre. The 76 subjects who fulfilled the inclusion criteria had an estimated fetal weight below the 10th centile for their gestation. Subsequent to enrolment, repeat ultrasound scans were performed weekly to determine growth velocity. Twenty-three infants whose change in fetal abdominal circumference between first and last scan was greater than -1.5 standard deviation scores (SDS) were assigned to the intrauterine growth retardation group (IUGR) while 53 infants whose fetal abdominal circumference changed less than 1.5 SDS were assigned to the small-for-gestational-age (SGA) group. Ten infants with normal intrauterine growth were enrolled as controls. Following delivery all infants had a neurological examination and a cranial ultrasound scan. At 1 year, 75 infants (87%) were traced and reassessed (49 SGA, 18 IUGR and eight controls) with a neurological examination and a developmental assessment. At birth, impairments were found in 27 (51%) of the SGA, 13 (57%) of the IUGR groups and one (10%) of the controls. At 1 year, 18 (37%) of the SGA subjects, six (33%) of the IUGR subjects and one (13%) of the control infant were impaired, including three (6%) of the SGA subjects and one (6%) of the IUGR subjects who were disabled. We conclude that in term fetuses with an estimated birthweight below the 10th centile for their gestation, the pattern of growth in the third trimester does not affect outcome at 1 year. In spite of optimum obstetric management, nearly one-third of the combined SGA and IUGR term fetuses had suffered some, albeit minor, neurological damage.

A discrete dipole scattering model is used to measure the passive microwave radiation scattered by snow particles having different shapes and sizes. The model results demonstrate that the shape of the snow crystal is insignificant in scattering microwave energy in the 37-GHz region of the spectrum.

Micromachining of polymers is an important field that has both immediate and future applications in diverse fields such as medicine, microelectromechanical systems, and photonics. In this work, ultraviolet pulsed laser ablation of polymethyl methacrylate (PMMA), polypropylene (PP), and polyethylene (PE) was performed using a KrF (krypton-fluoride) excimer laser in air, methanol, and ethyl alcohol. The size of the hole and etch depth were marginally increased in PMMA but were markedly reduced in PP and PE by the organics. There are other beneficial and detrimental effects of the organics in regard to the taper of the hole, contamination, thermal damage, and cracking that are explained based on laser-liquid-polymer interactions, which include self-focusing, chemical reactions, pressure-wave generation, and thermal quenching. Existing polymer ablation models were used to describe the observed etch depth versus incident laser energy fluence.

On Earth, the temperature regime is such that water is generally fairly close to its freezing point, and thus relatively small differences in climate affect how much snow and ice are present and whether or not the snow covering will be seasonal or last from one year to the next. On Mars, as on Earth, the presence of ice also plays a role in large-scale climate processes and it is important in controlling the abundance of atmospheric carbon dioxide (CO2) and water vapor. Passive microwave radiometry has been used to derive snow extent and snow depth on Earth, where scattering by snow (H2O) crystals is the dominant effect on the microwave radiation emanating from the ground and emerging from the snowpack. Microwave remote sensing may also prove to be useful for assessing the coverage and thickness of the frozen H2O and CO2 on Mars, but more exact information is needed on how both H2O crystals and frozen CO2 crystals scatter and absorb passive microwave radiation. In this study, CO2 crystals have been produced in a laboratory cold chamber with temperature conditions similar to those found on the polar caps of Mars, and detailed three-dimensional images of their size and shape have been made with a low-temperature scanning electron microscope. Unlike the much larger H2O snow crystals found on Earth, which typically range in size between 0.1 mm and 1.0 mm (radius), CO2 crystals are differently shaped and considerably smaller. Bipyramid crystals (base to base four-sided pyramids) are commonly observed, some as small as 1.0 μm. A discrete dipole model was employed to calculate the passive microwave radiation scattered and absorbed by crystals of various sizes and shapes. Modeling results indicate that the shape of the crystal, whether for frozen CO2 or H2O, is of little consequence in affecting extinction efficiency. However, owing to their smaller size, frozen CO2 crystals are more emissive than the H2O crystals in the 37 GHz region of the microwave spectrum. For the larger sizes of the modeled crystals, scattering dominates over absorption since the particles approach the size of the wavelength. The scattering values are 2 orders of magnitude larger than absorption for the 900 μm size snow particles. For CO2 crystals of 3.0 μm in size, absorption is 7 orders of magnitude greater than scattering.

OBJECTIVE. The purpose of this study was to evaluate the efficacy of Wallstents in treating inferior vena cava obstruction in hemodialysis patients. CONCLUSION. For the short and intermediate term, percutaneous placement of inferior vena cava Wallstents, followed by balloon angioplasty, is a safe and valuable technique for preserving the often limited central venous access in hemodialysis patients. To maintain patency, recurrent stenosis within the Wallstent can be treated with additional angioplasty.

Setup planning is a critical part of automated process planning. Setup is determined by several factors, tool approach direction and tolerance specification are two major ones. Most of the current process planning systems consider only the tool approach direction. This results sometimes in incorrect parts. To convert the tolerance requirements from design into a process plan, tolerance analysis must be applied. Correct datums must be selected for an optimum setup plan that will assure the required tolerances. This paper describes an approach that uses the tolerance specification in a feature based design system to generate setup plans with explicit datum elements. These setup plans are ranked by the number of setups required and the estimated accuracy of the resultant dimensions. The ranked setup plans are then reported to the fixture planner for fixture selection. The focus on this research is an automated tolerance analysis approach for selecting setups and datums for prismatic workpieces in the design ...

A self-organizing neural network, ART2, based on adaptive resonance theory (ART), is applied to the problem of feature recognition from a boundary representation (B-rep) solid model. A modified face score vector calculation scheme is adopted to represent the features by continuous-valued vectors, suitable to be input to the network. The face score is a measure of the face complexity based upon the convexity or concavity of the surrounding region. The face score vector depicts the topological relations between a face and its neighbouring faces. The ART2 network clusters similar features together. The similarity of the features within a cluster is controlled by a vigilance parameter. A new feature presented to the net is associated with one of the existing clusters, if the feature is similar to the members of the cluster. Otherwise, the net creates a new cluster. An algorithm of the ART2 network is implemented and tested with nine different features. The results obtained indicate that the network has significant potential for application to the problem of feature recognition.

In 5-axis machining, simultaneous change of tool orientation during machining affects the effective cutter shape, thus making the cutter selection difficult. In this paper, a maximum effective cutting radius approach is proposed to solve the cutter selection problem for multi-axis machining. The effective cutting radius of a tool is represented by a function of its physical tool size and the tool orientation angles, the incline angle λand the tilt angle ω. Optimal cutter selection is determined by geometric evaluation through the maximum effective cutting radius approach. A boundary-based approach for roughing cutter selection is also briefly discussed. The proposed methodology can be used to select cutters for the 3-, 4-, and 5-axis sculptured surface machining.

Two methods of measuring the amniotic fluid index (AFI) were subjected to tests of intra- and interobserver reproducibility. In the first method, amniotic fluid in each quadrant was measured by using the deepest pool perpendicular to the floor; in the second method, amniotic fluid in each quadrant was measured by using the deepest pool perpendicular to the uterine contour. Intraobserver and interobserver variability were assessed by using one-way analysis of variance and limits of agreement, respectively. Intraobserver standard deviations were all < 9 mm. When the AFI was measured using the first method, there was an inverse relationship between the interobserver difference and mean values of AFI. Plots of the differences between observers against their means showed that the lower the AFI, the greater the interobserver variability. No such correlation was noted when the AFI was measured by the second method. The limits of agreement (within which 95% of interobserver differences lie) were comparable for the two methods [(-42 mm to 29.4 mm) and (-46.4 mm to 41.6 mm), respectively]. The results suggest that the amniotic fluid index measured by the second method is more reproducible, especially in the presence of reduced amniotic fluid.

A longitudinal study of 20 uncomplicated pregnancies in Bangladeshi women was undertaken. Fetal growth was investigated by serial ultrasound scans performed between 26 and 38 weeks of pregnancy. Repeated measurements of abdominal circumference and estimates of fetal weight were best described by a log quadratic equation. The coefficients were not significantly different from those obtained from a previously reported study of fetal growth in 67 uncomplicated pregnancies with healthy outcomes in white Anglo-Saxon women. Further comparison between the two groups showed that the mean abdominal circumference and estimates of fetal weight of the Bangladeshi fetuses were smaller at 28, 32 and 36 weeks' gestation. These results suggest that, although Bangladeshi fetuses appear to be smaller than Anglo-Saxon fetuses, they grow at a similar rate during the third trimester. Copyright © 1995 International Society of Ultrasound in Obstetrics and Gynecology

An architecture for structuring and implementing an object-orientated process planning system for manufacturing is described. The primary objective of the architecture is modularity, where modularity is achieved mainly through polymorphism. The manufacturing objects are identified, as is the knowledge they own and the interactions between objects. Process planning is conducted solely with autonomous objects, and manufacturing tools are the primary actors. The architecture and its modularity are demonstrated with two working systems, one for sheet metal and one for turning.

Doppler ultrasound has been advocated as a useful tool to evaluate pregnancies with intrauterine growth retardation (IUGR). However, many previous studies have used smallness for gestational age (SGA) at birth to define IUGR. The ability of Doppler ultrasound to predict SGA, neonatal morphometric indices of wasting such as a low ponderal index, and perinatal morbidity is reviewed. Doppler assessment of the umbilical and uteroplacental vasculatures were inferior to ultrasound measurements of fetal size in the prediction of SGA. In low risk fetuses, umbilical artery waveform indices were of limited value in the prediction of neonatal morphometric indices of wasting. Within a group of high risk fetuses, Doppler assessment of the umbilical artery and, in particular, the middle cerebral and aortic vessels, were useful in predicting fetuses with neonatal wasting. Similar findings were noted in the prediction of perinatal morbidity. The review confirms the usefulness of umbilical artery Doppler waveform indices in the antenatal assessment of IUGR. Whilst preliminary studies appear to suggest that Doppler waveform indices of the middle cerebral and aortic vessels may confer an additional advantage in the antenatal assessment of IUGR, randomized controlled trials evaluating their effect on perinatal outcome and studies on the reproducibility of these indices need to be carried out before their widespread introduction into obstetric practice.

In a prospective observational study, the fatty acid content of human umbilical artery and vein wall phospholipids was determined in fetuses classified according to their change in abdominal circumference during the third trimester. Three groups were identified: appropriate for gestational age (AGA; 24 infants) and small for gestational age (SGA; 38 infants) with normal antenatal growth rate, and SGA with fetal growth retardation (22 infants). The venous linoleic acid (18:2 omega 6) content (expressed as a percentage of the total fatty acids identified) was greater in growth retarded SGA fetuses (3.5 (0.6)%) than in SGA fetuses with a normal growth rate (3.1 (0.5)%) and AGA fetuses (3.0 (0.5)%), whereas the venous contents of eicosatrienoic (20:3 omega 6) and docosahexaenoic acid (22:6 omega 3) were lower. In growth retarded SGA fetuses, the venous and arterial 20:3 omega 6 content correlated with the change in abdominal circumference. In SGA fetuses with a normal growth rate, lower contents of arterial 18:2 omega 6 and 22:6 omega 3 were associated with a smaller change in abdominal circumference and birth weight. Different metabolic derangements appear to underly normal and subnormal growth rate in SGA fetuses, suggesting that different strategies of dietary intervention may be required to aid fetal growth and reduce the sequelae of fetal growth retardation.

The aim of this study was to assess the intra- and interobserver variability of second-trimester uteroplacental continuous-wave flow velocity waveforms. The left and right uterine and arcuate resistance indices were measured in women having their routine booking scan at 16–24 weeks' gestation. Four experiments assessed the intra-observer between-frame variability, the intraobserver beat-to-beat variability, the intraobserver temporal variability, and the interobserver variability, using the limits-of-agreement method. The intraobserver between-frame variability was greater than the beat-to-beat variability at three of the four sites. The temporal variability was not significantly different between sites. There were wide interobserver limits of agreement with respect to the reference ranges, although they were greater at arcuate sites than uterine sites. These observations suggest that the reproducibility of the resistance index in continuous wave Doppler uteroplacental flow velocity waveforms is poor, particularly from arcuate sites. The uterine site is preferable and descriptive analysis may be better. Copyright © 1993 International Society of Ultrasound in Obstetrics and Gynecology

This paper discusses a methodology for automatic generation of assembly plans for three-dimensional mechanical products. The primary goal is to develop an effective way to describe and plan the assembly of mechanical products. The proposed methodology starts with the creation of solid models for the assembly design. Mating and collision information are inferred from the assembly solid models. A frame-based representation scheme is also used to explicitly represent the assembly non-geometric information. In generating assembly plans, & two-state planning scheme is used. In the initial planning, assembly plans are generated based solely on product geometry considerations. A three-level planning strategy has been developed which analyses the part connectivity relationships in a hierarchical manner and ensures collision-free insertion of individual parts. The initial assembly plans are further revised in the second stage under sequence: constraints derived from non-geometric properties. Both high-level assemb...

Serial ultrasonic measurements were performed in 67 Caucasian fetuses from 20 weeks' gestation until term to derive reference standards for abdominal circumference (AC) and estimated fetal weight (EFW). The variances of both AC and EFW increased with gestational age. Four mathematical models (linear, quadratic, Gompertz and Rossavik) were fitted to the log(10)(AC) and log(10)(EFW) data from each fetus using least squares regression analysis. The standard deviations of the residual error were greatest for the linear model. The linear model also overestimated the final log(10)(AC) while the linear, Gompertz and Rossavik models all overestimated the final log(10)(EFW) when these data were omitted from the fitting process. The individual quadratic constants were, therefore, used to produce 67 individual growth curves. Values of log(10)(AC) and log(10)(EFW) for each fetus at exact gestational ages between 20 and 40 weeks were derived by interpolation; the mean and standard deviation values were then used to derive centile ranges for abdominal circumference and estimated fetal weight. These standards should prove useful in the assessment of fetal growth.

In this decade, the Moore's law does not fit the trend of technological improvement any more. In order to keep the increasing rate of device density and I/O numbers, the size of devices shrink rapidly. In this kind of condition, the stack of integrated circuit (IC), which is also called three-dimensional integrated circuits (3-D ICs), is a preferable solution of the next-generation products. There are several techniques to conduct the power and signals between the chips in the stack and the ultra-fine pitch micro-bump is the most potential one. The soldering process used in micro-bump is a low temperature process which does not damage the devices in ICs. However, the line-to-bump structure causes the serious current crowding effect near the entrance point of current flow in bump and also makes the bump resistance much larger than expected. In this study, a Kelvin bump structure was fabricated to precisely measure the "REAL" bump resistance of micro-bump. From the past studies, resistance of a flip-chip solder bump is only several milli-Ohms. Unlike the results from flip-chip solder bumps, the bump resistance obtained in this study is about a hundred milli-Ohms, which is larger than flip-chip solder bump by more than ten times. The unexpected high bump resistance will bring significant RC delay between chips and reduce the performance of electric products. This phenomenon totally disobeys the design purpose of 3-D ICs which is to reduce the high resistance caused by the long distance between chips. As a result, investigating a method to reduce the resistance of micro-bump is an important issue in the application of micro-bump and development of 3-D ICs. Moreover, the bump resistances measured from different angles (0°, 60°, 120°, and 180°) were also obtained by our Kelvin bump structures. A finite elements analysis (FEA) is also applied in this study to observe the current density distribution in detail. The results of FEA fit the measurement ones quite well. The FEA shows that the current density distributes uniformly in solder bumps. However, this does not mean that the current crowding effect does not happen anymore. It still takes place in under-bump metallization (UBM) instead. The crowding ratio, a factor to indicate the level of current crowding, is larger than 30 in UBM. This means that the electromigration (EM) failure may occur in UBM, not in solder, so the EM failure will still a serious reliability issue in micro-bumps.

SUMMARY Sculptured surfaces often appear in mechanical parts of various industrial products as external form or the functional surface and are commonly found in moulds and dies. In this study a sculptured surface is denned by a non-uniform rational B-spline surface that provides the flexibility and freedom for surface description. Work proposed here includes the evaluation of machining information, decision for machining process sequence selection, and automatic cutter selection and path generation. Machining information is first evaluated by using series of hunt planes and calculating geometric shape, and constraints of the machining cavity. A decision on the process sequence in made based on the evaluated machining information. Cutter size is automatically determined by considering geometric constraints, maximum material removal rate in the roughing process, and minimum cutter movement with the required accuracy in the finishing process. Roughing is done by pocketing procedures that consider arbitrary s...

NC code generation, if done manually, forms the bottleneck in a production system. Hence automatic NC code generation forms an important part of a totally automated manufacturing system. Most of the existing systems for this task consider cutter path generation only for limited part geometry. The work proposed here considers both optimum cutter size selection and cutter path generation. The work done encompasses almost all the features found on prismatic parts, such as slots, steps, projections, etc. First the finishing and roughing tools are selected based on minimum cutter motion criterion, then algorithms for determining the area within the cutter centre can move are outlined. The final part of the research deals with optimizing the cutter movement within this region. So here we have developed the algorithms to select an appropriate cutter and also to generate the cutter path and NC code for machining a pocket using any given cutter.

During the last two years,twenty-seven bioreactors of upflow anaerobic sludge blanket(UASB) process were constructed and operated well to treat 3,300 m3/day of winery wastewater in six winery plants in Taiwan. Each UASB reactor was installed with an internal filter and a side-armed sludge settler to separate gas-liquid-solid effectively in 127 m3 of reactor volume.These six plants established good performance of UASB process with different organic loadings depending on different characteristics of the winery wastewater. Start-up performance of the modified UASB process in four winery plants was investigated.Bioactivity of anaerobic sludge in each UASB was evaluated by means of Biochemical Methane Potential (BMP)test. Biokinetics of Monod and Haldane models were employed to interpret the different sludge characteristics in terms of gas production rate. Scanning electronic microscopy also showed different morphology of sludge granules in three UASB systems.

The quest for completely automated process planning systems has exposed the lack of techniques capable of automatically understanding the stored CAD models in a manner suitable for process planning. Most current generations of process planning systems have used the ability of humans to translate the part drawing requirements into a form suitable for computer aided process planing. Recently, research advances have been made to improve the understanding of computer stored 3-D part models. The two approaches used are feature recognition and feature based design. This paper presents a state of the art review of feature recognition techniques developed and presents feature based design as an alternative. Process planning systems developed using both approaches are presented.

The purpose of this study was to determine the value and cost of obtaining routine chest radiographs after image-guided placement of internal jugular central venous catheters.We reviewed the records of 424 patients in whom 572 internal jugular catheters were placed by sonographic and fluoroscopic guidance over a 2-year period. Inspiratory and expiratory chest radiographs obtained immediately after each procedure were also reviewed.Routine postprocedural chest radiographs revealed no complications and did not alter the treatment of any patient. Delayed pneumothorax was detected after placement of two catheters (0.5%) when patient symptoms prompted additional radiographs.Immediate postprocedural chest radiographs are not routinely needed after image-guided insertion of internal jugular central venous catheters and unnecessarily add to the cost of patient care.