Search

Femtosecond-pulse laser pulses have been shown to hold great potential for high-precision micromachining. Much research has been done to characterize the laser parameters for predicting the feature size, and the most important of these is the number of pulses incident at each point of ablation. Theoretical modeling, so far, has been restricted to a single point where the number of pulses incident at each point of ablation depends on the pulse-repetition rate and the dwell time of the laser beam at that machining point. However, to make the theoretical model useful, a laser scanning system with the ability to fabricate complex microfeatures is considered in this work. In this case, the scanning resolution determines the number of pulses incident at each scanning point. This has been taken into account while presenting a theoretical and experimental analysis of the effect of the scanning resolution on the threshold fluence of the material. Results of ablation on a gold thin film were subjected to theoretical analysis to predict the feature size. In addition, the effect of the energy fluctuation of the laser on the feature size has been evaluated to predict the minimum achievable feature size for a gold thin film.

We analyze the dynamics of a spherical scaffold in rotating bioreactors (or clinostats). The idealized clinostat environment consists of a purely rotational flow that is perpendicular to a gravitational field. We confirm through a detailed analytical study that lift effects considerably alter the position of the equilibrium point reached by the scaffolds in the (vertical) direction collinear to the gravitational field. This result holds for small particle and shear Reynolds numbers. Our analysis shows that the inertial lift effect is negligible in the horizontal direction. We show that for all rotations of practical interest, and for the range of particle Reynolds number smaller than unity, the vertical coordinate of the equilibrium point is strongly affected by consideration of lift effects. For light (heavy) particles, inclusion of lift in the formation forces the equilibrium position to be below (above) the horizontal plane that contains the axis of rotation. The equilibrium point for light particles is stable and therefore is observable experimentally. The equilibrium point for heavy particles is unstable. We also estimate the stress level applied to the scaffold and derive an algebraic expression that indicates that the stress level acting on the scaffold decreases with increasing shear Reynolds number.

Use of a glassy carbon electrode modified by adhered microcrystals of fullerene-C 60 mediates the oxidation of cysteine in the presence of aqueous potassium-containing electrolytes. Under conditions of cyclic voltammetry, the potential for the oxidation of cysteine is lowered by approximately 100 mV and current is enhanced significantly relative to the situation prevailing when a bare glassy carbon electrode is used. Additional mediation occurs when the potential range covered includes that of C 60 /C 60 n − redox couples. The sensitivity under condition of cyclic voltammetry is significantly dependent on pH, temperature and C 60 dosage. Excellent analytical and/or recovery data are obtained with vitamin pill, cassamino acid (hydrolyzed casein) and for a range of beverages.

In this paper, integration of interference phenomenon into femtosecond laser micromachining was reported as the femtosecond laser pulses were reshaped spatially to perform ablation. The generation of circular interference pattern was demonstrated by overlapping infrared femtosecond laser pulses. The interference pattern was subsequently focused on a copper substrate to ablate microstructures of concentric circular rings. The present technique is expected to open up new applications in the areas of rapid fabrication of micro-Fresnel lenses, hybrid microlenses and lens arrays.

Voltammetric studies on C60 fullerene particles adhered to an electrode surface by solvent casting or mechanical transfer exhibit evidence of nucleation and growth controlled processes for the C600/– and C60–/2– solid state when the modified electrode is in contact with acetonitrile solutions containing NBu4+ electrolyte. Although peak potentials and peak separations are dependent on scan rate as well as the amount of deposit and temperature, potentials obtained using a zero-current extrapolation method are almost independent of all these parameters. These data enable reversible potentials of –816 and –1168 mV vs. Ag/Ag+ to be obtained in acetonitrile (0.1 M NBu4PF6) respectively for the processes: \({\rm C}_{{\rm 60}} \left( {{\rm solid}} \right) + {\rm NBu}_{\rm 4}^ + \left( {{\rm solution}} \right) + {\rm e}^ - {\rm }\buildrel {} \over \rightleftharpoons {\rm NBu}_{\rm 4} {\rm C}_{{\rm 60}} {\rm (solid)} \) and \( {\rm NBu}_{\rm 4} {\rm C}_{{\rm 60}} \left( {{\rm solid}} \right) + {\rm NBu}_{\rm 4}^{\rm + } \left( {{\rm solution}} \right){\rm + e}^{\rm - } \buildrel {} \over \rightleftharpoons \left( {{\rm NBu}_{\rm 4} } \right)_{\rm 2} {\rm C}_{{\rm 60}} \left( {{\rm solid}} \right) \) . Images obtained by scanning electron microscopy reveal that both the crystalline and particle size is enhanced by 60 s of reductive electrolysis, with the detected (NBu4)2C60 crystals being slightly larger than those of (NBu4)C60. After a short period of potential cycling or controlled potential electrolysis, it is concluded that the data obtained by either method of surface adherence are almost indistinguishable, as are their morphologies.

This article presents experimental results of precision machining of steel alloys with polycrystalline diamond tools. Ultrasonic vibration-assisted cutting was tried out for expanding the application of diamond tools for high-precision and high-quality machining of ferrous materials. The experimental results show that compared with conventional turning, the cutting performance, in terms of cutting force, surface finish, and tool life, was improved by applying ultrasonic vibration to the cutting tool. The cutting forces and tool wear measured in vibration cutting are much lower than those in conventional cutting. The tool wear mechanism was discussed on the basis of the observation of wear zone.

Composites as a separate class of engineering material have found many applications in aerospace industries where high performance and safety are a prime concern. A review has been done in order to provide a comprehensive analysis on various types of composites used in the aerospace industry, emphasizing on the features, properties, advantages, limitations, and emerging trends in the field.

The synthesis and complete characterization by multinuclear NMR, infrared, and Mossbauer spectroscopy, by single crystal X-ray analysis, as well as by electrospray mass spectrometry of the new soluble triorganotin fluoride Me2PhSnF (1) is reported. The crystal structure of 1 reveals a rod-like polymeric structure in the solid state. Solutions of 1 in apolar solvents, such as toluene, contain mixtures of interconvertible oligomers. Ab initio MO calculations on model compounds H3SnF, [H3SnFSnH3]+, and [FH3SnFSnH3F]− indicate that the Sn−F bonds are substantially ionic in character, and suggest open-chain species, rather than cyclic species. In donor solvents, such as pyridine, 1 forms complexes with the solvent, such as Me2PhSnF·pyridine. The solid-state structure of (Me3SiCH2)3SnF (2) is reformulated as monomeric with a weak intermolecular Sn···F interaction that gives rise to a [4+1] coordination. The relative short Sn−Sn separation enables the fluorine atoms to oscillate (flip-flop) between two neighboring (Me3SiCH2)3Sn− groups, which is expressed in the X-ray experiment by a dynamic disorder. Ab initio MO calculations on a model compound, [H3SnFSnH3]+, suggest only a small energy barrier for the flip-flop motion. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2003)

Femtosecond lasers have considerable advantages over conventional laser sources for microfabrication. Even features with sizes very much less than the focused beam spot size of the laser can be fabricated using these lasers. Considering the potential of the laser for microfabrication, a valuable technique has been developed for the fabrication of binary photomasks by using femtosecond laser ablation of thin films. This is a single-step process and is faster compared to the complex multi-step lithography process currently used for photomask fabrication. A dispersion compensated acousto-optic scanning system has been developed for scanning the beam to transfer the required pattern to the mask blank. The applicability of this technique for microfabrication has been proven conclusively by fabricating microfeatures with the photomask fabricated by this technique. This can be made industrially viable by incorporating femtosecond laser sources with high pulse repetition rates.

Photomasks are the backbone of microfabrication industries. Currently they are fabricated by a lithographic process, which is very expensive and time consuming since it is a multi-step process. These issues can be addressed by fabricating photomasks by direct femtosecond laser writing, which is a single-step process and comparatively cheaper and faster than lithography. In this paper we discuss our investigations on the effect of two types of laser writing techniques, namely front- and rear-side laser writing, with regard to the feature size and the edge quality of a feature. It is proved conclusively that for the patterning of masks, front-side laser writing is a better technique than rear-side laser writing with regard to smaller feature size and better edge quality. Moreover the energy required for front-side laser writing is considerably lower than that for rear-side laser writing.

Shock absorber is a part of the suspension system which provides comfort experience while driving. Resonance, a phenomenon where forced frequency is coinciding with the natural frequency has significant effect on the shock absorber itself. Thus, in this study, natural frequencies of the shock absorber in a 2 degree-of-freedom system were investigated using Wolfram Mathematica 11, CATIA, and ANSYS. Both theoretical and simulation study how will the resonance affect the car shock absorber. The parametric study on the performance of shock absorber also had been conducted. It is found that the failure tends to occur on coil sprung of the shock absorber before the body of the shock absorber is fail. From mathematical modelling, it can also be seen that higher vibration level occurred on un-sprung mass compare to spring mass. This is due to the weight of sprung mass which could stabilize as compared with the weight of un-sprung mass. Besides that, two natural frequencies had been obtained which are 1.0 Hz and 9.1 Hz for sprung mass and un-sprung mass respectively where the acceleration is recorded as maximum. In conclusion, ANSYS can be used to validate with theoretical results with complete model in order to match with mathematical modelling.

No abstract available.

The syntheses and crystal structures of the eight-membered cyclo-stannasiloxanes cyclo-[t-Bu(OH)Si(OSnt-Bu2O)2Si(OH)t-Bu] (1) and cyclo-{t-Bu2Si[OSn(CH2SiMe3)2O]2Sit-Bu2} (2) as well as the synthesis of the six-membered cyclo-stannasiloxane cyclo-{t-Bu2Si[OSn(CH2SiMe3)2]2O} (3) are reported. Compound 1 crystallizes as its trans isomer, but the cis isomer dominates in solution. In agreement with the experimentally obtained results, ab initio and DFT calculations on the model compounds cyclo-(H2SiO)4 (4), cyclo-[H2Si(OSnH2)OSiH2] (5), cyclo-O(H2SiOSnH2)2O (6), and cyclo-[H2Si(OSiH2)OSnH2] (7) indicate that the energetic preference to adopt puckered structures increases and the ring flexibility decreases with an increasing number of tin atoms in the ring. The rich diversity of puckered conformations is attributed to the steric demand of the different organic substituents.

The objective of this work was to compare the burned gas temperature measured using coherent anti-Stokes-Raman scattering (CARS) with the predictions of a multiple-zone computer simulation of combustion. The tests were at various engine operating conditions with different fuels. Mean cycle modelling was used initially to obtain the appropriate heat transfer tuning parameters for the engine simulation by matching to the cylinder pressure. The predicted mean cycle burned gas temperatures gave good agreement with the measured mean temperatures. Similarly, cycle-by-cycle modelling produced burned gas temperatures that agree with the measured values. This work showed that the multi-zone computer simulation could accurately predict the burned gas temperature once the fuel burn rate and completeness of combustion have been analysed and the model tuned correctly. The effects of methanol, methane, toluene and iso-octane on the burned gas temperature were investigated. It was found that the fuel burn rate and the adiabatic flame temperature affected the burned gas temperature. Fuels with a high burn rate (such as methanol) have a lower burned gas temperature towards the end of the engine cycle. Toluene has the highest adiabatic flame temperature and hence gave the highest burned gas temperature.

Hydrogen-free amorphous carbon films were deposited at different deposition bais voltage on a single silicon wafer by a process known as Filtered Cathodic Vacuum Arc (FCVA). The influences of different deposition bias voltages on the microstructure and the properties of thin tetrahedral amorphous carbon (ta-C) films, such as surface roughness, film mass density and thickness, have been studied by means of the x-ray reflectivity technique (XRR) for the first time. The microstructure of these films deposited on silicon wafers was stimulated by a four-layer model consisting of a ta-C layer, a mixed ta-C:Si layer, Si-O layer and the silicon subtrate. The mixed ta-C:Si layer consisting of the mixture of ta-C and silicon simulates the carbon ion impinging / diffusion into the surface of the silicon substrate. The mass density and the roughness of the film are found to be dependent on the impinging ion bombardment energy. The mass density increases with increase in ion bombardment energy up to 100 eV. Beyond 100 eV, the mass density decreases with further increase in ion bombardment energy up to 100 eV. Beyond 100 EV, the mass density decreases with further increase in ion bombardment energy. The surface roughness decreases with increasing ion bambardment energy to a minimum value at 100 eV, after which it increases with further increase in ion bombardment energy. The thickness of the films obtained by XRR technique correlates well with the thickness measurement obtained by spectral reflectometry. The existence of the Si-O layer was verified by Auger depth profiling.

The growing antler of 1-year-old red deer is an excellent system in which to study processes involved in ``cartilage model'' endochondral-type bone growth. Antlers grow from the tip, permitting the developmental sequences of bone formation to be studied as distance-dependent phenomena, in which early processes can be observed at the distal end, and later events are sequentially more proximal. Quantitative light microscope histochemical assays for alkaline phosphatase (ALP) and phosphodiesterase I (PDE I) were used to determine the activities of these two phosphohydrolases in relation to antler mineralization and remodeling. Both enzymes were absent in proliferating young cartilage near the end, but progressively increased in activity in a proximal direction. ALP levels were maximal when mineralization was just beginning, whereas PDE I activity was greatest more proximally, where mineralization was more complete. This study provides strong indirect evidence that each of these enzymes has a function in mineralization, but that their roles are not identical.

To obtain insights into the photophysical properties of collision-free T1(a 3A2) thiophosgene, Cl2CS, the cavity ringdown (CRD) spectrum of the T1←S0 absorption system was recorded under supersonic jet conditions and compared with the corresponding excitation spectrum of the total emission. It was found that none of the T1←S0 bands in the CRD spectrum appears in the excitation spectrum, indicating that the T1 thiophosgene decays almost exclusively by the nonradiative T1→S0 intersystem crossing (ISC). An estimation of the T1 nonradiative lifetime was made using the T1–S0 spin-orbit coupling and the Franck–Condon factors for the T1→S0 ISC based on the ab initio equilibrium structures and vibrational frequencies for the T1 and S0 states, computed at the MP2/6-31G(d,p) and MP4/6-31G(d,p) level of theory. The nonradiative life, calculated as the 1/e of the survival probability, is approximately 20 ps for barrier heights of 770–845 cm−1 and out-of-plane angles of 32.07°–32.69°. (The thiophosgene adopts a pyrami...

Unhydrogenated amorphous carbon films were deposited at different temperatures on a single silicon wafer by a process known as Filtered Cathodic Vacuum Arc. A transition from diamond-like properties to graphitic properties was observed at the substrate temperature of 200°C. This change of properties upon transition includes a change in compressive stress, frictional coefficient and density. The variation of results is consistent with the subplantation model, which emphasizes the role of carbon atoms trapped in the subsurface layers in the evolution of a dense sp 3 -rich phase at room temperature. At higher temperature (>200°C) diffusion of carbon atoms to the surface of the evolving film releases internal stress and leads to the formation of a graphitic sp 2 phase. Based on x-ray reflectivity measurements, it was found that a thin interlayer formed between the tetrahedral amorphous carbon film and the silicon substrate contributes greatly to the good fitting of the spectra. The thickness of this interlayer is independent of the temperature. The optical properties were found to undergo a more gradual transition with the deposition temperature.

Geometric dimensioning and tolerancing (GDT) has been playing an important role in specifying the geometry of part features during the product design stage. Tolerance stack analysis is then used to study the conformity of the parts to the tolerance zone. Performing stack analysis is time consuming because geometric tolerances are complex to compute. This paper presents a technique to formulate the bonus and shift tolerances (due to positional callout) and convert them to equal bilateral expressions as in a coordinate tolerance system. An example is used to demonstrate the effectiveness of the expressions. The usage of the expressions is less conceptual and this makes the application simple and direct. Most importantly, the results are shown to be accurate and reliable.

Compounds of the type R3Sn(OSO2CF3) (triorganostannyl trifluoromethanesulfonates, R = Me, Bu, Ph) were synthesized and investigated in solution using electrospray mass spectrometry. The mono-acetonitrile adduct [R3Snz(CH3CN)]+ is the dominant ionic species in acetonitrile solution, with a weaker signal owing to R3Sn+. The relative intensity of R3Sn+ increases significantly upon the use of dichloromethane as a solvent. Variable temperature 119Sn NMR studies were also undertaken on the trimethylstannyl and triphenylstannyl trifluoromethanesulfonates in dichloromethane solution. The 119Sn chemical shifts and Lewis-base adduction studies reveal that the trioganostannyl trifluoromethanesulfonates are only slightly more Lewis-acidic than the corresponding triorganostannyl chlorides. These solutions are too labile to be studied on the NMR timescale.

This paper introduces a new approach to predicting the natural resting behavior of a part of irregular prismatic cross-sectional shape. The methods proposed by Boothroyd, Redford, Poli, and Murch (1972) and Boothroyd and Ho (1977), successfully analyzed parts whose centers of gravity were located at the geometric center. The hypothesis presented here employs the centroid solid angle of parts of irregular cross-sectional shape with virtual resting faces, such as the L-section. It postulates that the probability of the respective natural resting surfaces of a part coming to rest is directly proportional to the centroid solid angle and inversely proportional to the height of the center of gravity from that surface. The proposed hypothesis is compared with the Energy Barrier Method and experimental results obtained from drop-tests of the L-shaped part. The theoretical results agree well with the experimental results, with the maximum deviation not exceeding 6 percent.

In the present day electronics industries, plastics are widely used to make electronic connectors and IC chips. As these plastic components, which are soft in nature, are commonly produced in high volume and oriented in a vibratory bowl, the authors are motivated to conduct a study on the natural resting aspects of such components. Literature survey indicates that till today, no work has ever been done with regard to soft materials dropped on a soft surface. The soft materials, in this respect, refers to parts constructed from materials such that they do not necessarily dig into their landing surfaces. Past experiments, have been conducted to verify the Centroid Solid Angle (CSA) method postulated by Ngoi, Lye, Chen1 and Ngoi, Lim, Lee,2,3 and the Energy Barrier Method postulated by Boothroyd and Ho,4 but they were constrained to hard materials dropped on a hard and soft surface. Hence this paper is intended to verify the validity of the CSA method towards soft materials dropped on a soft surface by employing a vibratory bowl to effect a change in the experimental parts towards its natural resting aspect. The material chosen for the study is acrylic.

The energy barrier method, first proposed by Boothroyd and associates, can be used to determine the probabilities of the natural resting aspects of objects to be conveyed on and oriented by vibratory devices. However, for parts of uniform cross-section other than square or rectangular ones, the application of the method can be intractable. In such cases, Boothroyd and associates recommended circumscribing the part by a cylinder and using the energy barrier for the cylinder to approximate the probabilities of the natural resting aspects of the part. This approximation is understandably inexact although computationally expedient. This paper outlines the CAD (computer aided design) computation of the probabilities from the energy barriers for two objects: one, a triangular prism with equilateral sides (representing objects with adjacent faces that are not mutually perpendicular) and the second, an L-shaped prism with a virtual resting aspect. The significance of the centroid plane of the part in the determination of the probabilities is discussed. The CAD computations were carried out using the Graphical Interface Programming (GRIP) Language of McDonnell Douglas' UniGraphics II™ CAD system running on a DEC 9000 workstation.

This paper seeks to verify that the existing hypotheses, which predict the natural resting aspects of small engineering parts on soft and hard surfaces, are able to predict the orientation of parts on the track of a vibratory bowl at different vibrating amplitude levels. Most of the existing hypotheses developed were verified using the “drop test” method in which parts were repeatedly dropped from a certain height onto a surface in order to analyse the natural resting behaviour of parts. This paper describes an attempt to conduct accurate experiments in the laboratory to examine the probabilities of the feed orientation of square and rectangular components of different aspect ratios by varying the vibration amplitude levels and surface textures of the vibratory bowl. The experimental results were compared with the predictions of the hypotheses postulated first by Ngoi, Lye and Chen [1], secondly by Boothroyd [2] and thirdly by Ngoi, Lim and Lee [3]. The experimental results were found to agree well with those predicted by the hypotheses. Moreover, it is also observed that the vibrating amplitude of the vibratory bowl does not significantly affect the orientation of the parts.

This paper verifies the existing hypotheses which predict that the natural resting aspects of small engineering parts on soft and hard surfaces are able to predict the orientation of parts on the track of a vibratory bowl at different vibrating amplitude levels. Most of the existing hypotheses developed were verified using the "drop test" method in which parts were repeatedly dropped from certain height to a surface in order to analyze the natural resting behavior of these parts. This paper describes an attempt to conduct accurate experiments in the laboratory to examine the probabilities of feed orientation of T-shaped components of different aspect ratios by varying the amplitude levels and surface textures of the vibratory bowl. The experimental results were compared with the predictions of the hypotheses postulated firstly by Ngoi et al.1 and secondly by Ngoi et al.2 The experimental results were found to agree well with those predicted by the hypotheses. Moreover, it is also observed that the vibrating amplitude of the vibratory bowl does not significantly affect the orientation of the parts.

This study investigates whether the presence of serum and plasma anti-myelin oligodendrocyte glycoprotein (MOG) and anti-myelin basic protein (MBP) in patients presenting with a clinically isolated syndrome compatible with demyelination (CIS) predicts early conversion to multiple sclerosis (MS). Forty-seven patients with CIS (46 with optic neuritis) had anti-MOG and anti-MBP antibodies analysed at baseline, and clinical and magnetic resonance imaging assessments. There was no evidence that the MS status based on either the McDonald or Poser criteria relates to the antibody status.

Level anticrossings and quantum beats have been observed for the fluorescence from single rotational levels of the vibrationless S1 pyrimidine in a supersonic free jet. The density of triplet levels (ρ) and the coupling matrix elements (v) deduced from the data obtained for R(0) transition confirm that the singlet–triplet coupling belongs to the weak coupling limit (vρ≪1) of interstate interaction, in which electronic relaxation from the prepared singlet state to the triplet manifold does not occur in the absence of collisions.

In this paper, the stiffness loss of general composite laminates with transverse cracks under mixed-mode loading is analyzed. The effective stiffnesses of the laminates are assumed to be functions of the nonlinear internal state variables (ISVs), which are dependent on crack densities, ply constraints, and crack opening profiles. The ISV corresponding to Mode I cracking is obtained from a series of finite element analysis. The ISV corresponding to Mode III cracking can be related to the Mode I ISV by considering geometrical constraints arising from the layup, for a laminate under tensile loading. Theoretical predictions of stiffness loss of glass/epoxy and graphite/epoxy composite laminates with transverse cracks are compared with experimental data available from published sources, for crossply, angleply, and quasi-isotropic laminates. In addition, the model enables the contributions from respective modes to the overall stiffness reduction to be determined. Results of analyses have shown good and excellent agreement with published experimental data from other researchers.

This paper presents a new approach for analysing the natural resting behaviour of a non-rotational component. The method employs the energy envelope concept to analyse the natural resting of a component. The resultant curves for all the prisms agree well with Boothroyd's theoretical curve and Boothroyd's experimental data.

Studies on risk factors for drug non-compliance have not taken into account the possibility of correlated outcomes. We therefore conducted a study into risk factors for non-compliance by using analysis techniques that adjust for these correlations (longitudinal data analysis). Data were obtained from interviews and pharmacy records in a cross-sectional survey in Amsterdam. The subjects were 157 elderly people aged 70 years or older. Of these subjects, 37 were residents of a home for the elderly, 40 were community-dwelling elderly who needed to be visited regularly by a district nurse, and 80 were community-dwelling elderly who did not need to be visited by a district nurse. Most drugs (78%) were used according to the directions; the remainder (22%) were not used as intended. Odds ratios (95% confidence intervals) for non-compliance for moderate and poor/wrong knowledge of the purpose of a drug as compared with good/correct knowledge were 2.8 (1.2-6.7) and 4.2 (1.5-12), respectively. Drug regimens of two times daily and more than two times daily were associated with odds ratios for non-compliance of 4.5 (1.6-12) and 4.2 (1.7-11), respectively, compared to a regimen of once daily. Compliance increased if a drug was prescribed by a specialist instead of a general practitioner odds ratio 0.1 (0.04-0.4)]. There was no significant relation between compliance and the number of drugs prescribed to a patient, sex, age, living situation, patient group, or perceived effect. This study, which was based on longitudinal data analysis, demonstrates that in elderly people non-compliance with drug therapy is related to the knowledge of purpose of a drug, the complexity of a drug regimen, and the type of prescriber. The positive association between compliance and the number of drugs prescribed found in former studies was not confirmed.

Although many Asians regard puffer fish as a delicacy since ancient times, puffer fish (Lageocephalus scitalleratus) is also a well-known source of possibly lethal food poisoning. The fish is gaining popularity in Singapore and can be found in quite a few restaurants now. Puffer fish contains tetrodotoxin (TTX), a potent poison affecting the neural pathway. Puffer fish poisoning may cause a constellation of symptoms, such as giddiness, numbness and tingling sensation of the mouth, paresthesia, and muscle weakness. Severe cases may present with respiratory depression, circulatory failure, and death. TTX poisonings have been reported in Japan, Taiwan, Hong Kong, Bangladesh, and the United States (Haque et al. 2008). We report a case of mild poisoning and suggest observation for such cases.

SUMMARY This papers introduces a new approach to predicting the natural resting behaviour of a prismatic part of irregular cross-section. The methods proposed by Boothroyd et al. (1972) and Boothroyd and Ho (1977) were successful in analyzing parts with geometrically simple configurations, although empirical factors were used in the former case. For the past 16 years or so, however, no attempt has been made to analyze pans with complex shapes. Up to now, the study of the natural resting behaviour of complex shapes was conducted by approximating or simplifying the two stated methods. Considering the fact that most parts encountered in industry are not geometrically simple, this practice is the norm rather than the exception. The hypothesis presented in this paper proposes that the probability of apart coming to rest on any of its many feasible resting surfaces is directly proportional to the centroid solid angle and inversely proportional to the height of the centroid from that surface. No empirical factor...

This paper presents a new approach in the analysis of the natural resting behaviour of a component with a displaced centre of gravity. The methods proposed by Boothroyd et al. (1972), and Boothroyd and Ho (1977), can analyse parts with the centre of gravity located al their geometric centre. Hitherto, the only attempt at analysing pans with displaced centres of gravity entailed the use of empirical factors (Boothroyd et al. 1972). The hypothesis presented herein makes use of the centroid solid angle concept to analyse a component with a displaced centre of gravity. The proposed hypothesis postulates that the probability of a part coming to rest in its various natural resting aspects is directly proportional to the magnitude of the centroid solid angle and inversely proportional to the height of the centre of gravity from that aspect. The experimental results of drop tests conducted on a test specimen corroborate the hypothesis within a maximum deviation of 4%. This is the first successful attempt in the a...

In electronics manufacture, discrete components are commonly conveyed and oriented in high volume devices such as vibratory bowl feeders, the efficiencies of which depend, to a large extent, on some fore-knowledge of the probabilities of the orientation of the components prior to entering the devices. The research discussed in this paper is motivated by the fact that a simple and effective analysis of these probabilities is wanting. A new approach, employing the concept of the centroid solid angle of the component, is presented. The hypothesis postulates that the probability of a component resting on a specific aspect is directly proportional to the magnitude of the centroid solid angle and inversely proportional to the height of its centroid from that aspect. When the hypothesis is applied to prismatic parts of square, triangular, hexagonal, cylindrical and rectangular cross-sections, the results were found to agree well with those derived by the Energy Barrier Method postulated by G. Boothroyd and associates.

In the research described in this paper, an approach that utilizes deep models of features to transform a component design represented by neutral features into domain-specific features has been developed. The neutral features are known as feature-oriented generic shapes (FOGSs). The proposed approach provides the flexibility needed to represent both the deep and shallow knowledge required in feature mapping. A deep model of a feature is represented in the form of a face connectivity graph (FCG) that embodies deep knowledge about its geometry, while other non-geometrical information can be represented as rules or procedural functions. By comparing the original faces of a product model with those of the resultant evaluated boundary model, faces of interest can be easily extracted and described using FCGs. A FCG can then be examined to determine its class and the relevant parameters for applications in such domains as process planning. The mapping shell is designed with layered architecture that makes it highly appropriate for implementation using blackboard technology.

This paper proposes the construction of an energy envelope that can be used to advantage with the energy barrier method to analyse the natural resting aspect of engineering parts destined for automatic assembly. Unlike the energy barrier method, the energy envelope does not require any visualization of the projection of the energy barrier on the aspect of interest. The energy envelope is the three-dimensional topology of the changes in height of the centroid, as the part attempts changes of aspect. The paper describes how it may be computed in a CAD (computer aided design) solid modeller. The results of applying the energy envelope to prisms of square and cylindrical cross-sections are the same as those predicted by the energy barrier method. When extended to the analysis of a rectangular prism, the results were consistent with Boothroyd's dynamic solution and Boothroyd's experimental data. This conclusion is encouraging as there is no irrefutable evidence that the energy barrier method may be applied to the analysis of the rectangular prism.

IntroductionAlcohol intoxication is often involved in the commission of criminal behaviors that are risky and involve personal confrontation. Individuals who reported having three or more drinks before driving exhibited greater impulsivity when under the influence of alcohol than did those who did not report heavy drinking before driving.ObjectivesThe present study utilized the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) to compare the characteristics of individuals with a single driving while intoxicated (DWI) offense with individuals who were multiple DWI offenders and to identify whether there was a typical profile for multiple offenders.MethodsThe charts of patients were examined in terms of demographic characteristics including age, sex, employment, and education; the MMPI scores of the two groups were compared using an independent t-test, and we identified the typical profile of multiple DWI offenders by using hierarchical cluster analysis with Ward's method.ResultsScores on the F and the depression (D) scales of the MMPI-2 were significantly higher among multiple offenders than among first offenders. The multiple offenders-I group obtained relatively high scores on the D and psychopathic deviate (Pd) scales, and the multiple offenders-II group had low scores on both the hypomania (Ma) and social introversion (Si) scales. Thus, some multiple offenders may have poorer emotional adjustment, characterized by tendencies toward psychopathic deviance, mania, and depression, as well as psychopathological characteristics associated with patients with alcohol-use disorders.ConclusionThe present findings suggest that multiple offenders should be considered a high-risk group for alcohol-use disorders and recurrent drunken driving.Disclosure of interestThe authors have not supplied their declaration of competing interest.

SUMMARY When a product is to be manufactured in large quantities, automation and high-volume manufacturing processes are often considered as an attractive means to reduce costs and improve quality and productivity. While this is usually the case, it must be noted that product redesign, as a cost-cutting tool, can generate even greater benefits. In many cases, redesigned products are often optimized to the point where cost reduction can approach 90%. In addition, the costs of material for the various component parts and their manufacture and assembly are also greatly reduced. Not only are costs reduced, the quality, reliability and performance of the product are usually enhanced. This paper discusses how product redesign can be deployed as a cost-cutting tool to reduce the manufacturing cost and to enhance quality and performance. The cost-cutting tool is used in a case study to optimize the stamping process.

The spread of avian influenza has caused severe deaths in poultry and humans. It is important to understand migratory raptors flyways by monitoring their migration patterns. Ground counting is the oldest and easiest method to count the population of migratory raptors. The observers recognize the species of migratory raptors based on size, colour and song and flying characteristic. However, ground counting of big flocks of migratory raptors often faces difficulties due to the raptors' mobility and size. When the size of the flocks increases, ground counters will tend to produce more errors in their counting. Besides, ground counters will feel tired and easily lost their concentration when waiting for the migratory raptors for a long period of time. Therefore, the accuracy of this ground count method is questionable. This paper proposed the usage of optical remote sensing coupled with the image processing techniques to study the migratory raptors pathways. During the development of the software system, different image processing techniques were evaluated and enhanced for developing this monitoring system. The proposed mathematical thresholding technique is able to segment the raptors image from the background effectively.

Ten years of latitudinal variation of minimum Outgoing Longwave Radiation (OLR) over South East Asia was examined by using weekly OLR data from National Oceanic and Atmospheric Administration (NOAA) polar-orbiting satellites. The study was carried out using data collected from January 2000 to December 2010 which covered a region from longitudes 95°E–110°E; latitudes 20°N–20°S. Fourier function fitting was used to show the annual propagation of minimum OLR and created a new model of latitudinal variation of minimum OLR. The created model can be used to examine the latitude where minimum OLR occur.

Women from high-risk families consider preventive measures for breast cancer including screening. Guidelines on screening differ considerably regarding starting age. We investigated whether age at diagnosis in affected relatives is predictive for age at diagnosis. We analyzed the age of breast cancer detection of 1,304 first- and second-degree relatives of 314 BRCA1, 164 BRCA2 and 244 high-risk participants of the Dutch MRI-SCreening study. The within- and between-family variance in the relative's age at diagnosis was analyzed with a random effect linear regression model. We compared the starting age of screening based on risk-group (25 years for BRCA1, 30 years for BRCA2 and 35 years for familial risk), on family history, and on the model, which combines both. The findings were validated in 63 families from the UK-MARIBS study. Mean age at diagnosis in the relatives varied between families; 95% range of mean family ages was 35-55 in BRCA1-, 41-57 in BRCA2- and 44-60 in high-risk families. In all, 14% of the variance in age at diagnosis, in BRCA1 even 23%, was explained by family history, 7% by risk group. Determining start of screening based on the model and on risk-group gave similar results in terms of cancers missed and years of screening. The approach based on familial history only, missed more cancers and required more screening years in both the Dutch and the United Kingdom data sets. Age at breast cancer diagnosis is partly dependent on family history which may assist planning starting age for preventive measures.

Uncovering the mechanisms that govern the maintenance of stem-like cancer cells is critical for developing therapeutic strategies for targeting these cells. Constitutive activation of c-Jun N-terminal kinase (JNK) has been reported in gliomas and correlates with histological grade. Here, we found that JNK signaling is crucial for the maintenance of 'stemness' in glioma cells. Sphere-cultured glioma cells showed more phosphorylation of JNK compared with serum-containing monolayer cultures. Importantly, blockade of JNK signaling with SP600125 or small interfering RNAs targeting JNK1 or JNK2 significantly reduced the CD133(+)/Nestin(+) population and suppressed sphere formation, colony formation in soft agar, and expression of stem cell markers in sphere-cultured glioma cells. Intriguingly, sphere-cultured glioma cells exhibited enhanced expression of Notch-2, but not Notch-1, -3 or -4, and JNK inhibition almost completely abrogated this increase. Blocking the phosphoinoside 3-kinase (PI3K)/Akt pathway with LY294002 or si-Akt also suppressed the self-renewal of sphere-cultured glioma cells. PI3K, but not Akt, had a role as an upstream kinase in JNK1/2 activation. In addition, treatment with si-JNK greatly increased etoposide- and ionizing radiation (IR)-induced cell death in glioma spheres. Consistent with glioma cell lines, glioma stem-like cells isolated from primary patient glioma cells also had a higher activity of JNK and Notch-2 expression. Importantly, inhibition of JNK2 led to a decrease of Notch-2 expression and suppressed the CD133(+)/Nestin(+) cell population in patient-derived primary glioma cells. Finally, downregulation of JNK2 almost completely suppressed intracranial tumor formation by glioma cells in nude mice. Taken together, these data demonstrate that JNK signaling is crucial for the maintenance of self-renewal and tumorigenicity of glioma stem-like cells and drug/IR resistance, and can be considered a promising target for eliminating stem-like cancer cells in gliomas.

In general, the load-bearing capacity of laminated composites can remain significant despite the presence of damage in the constituent plies. The types of damage frequently encountered in laminated composites include delamination, matrix cracking, fibre breakage and fibre-matrix debonding. It is useful, for the purpose of damage tolerance analysis, to be able to predict and correlate the extent and severity of damage with changes in the mechanical properties of the composite laminate. This paper describes a series of finite element parametric studies performed for cross-ply laminates containing uniformly distributed transverse matrix cracks. Results of the analysis are used in a theory for damaged composite laminates to predict changes in laminate stiffness.

Correct part orientation has been the key to many successful automation applications, and often vibratory bowls were used. Traditionally, the design and tooling of the vibratory bowls are limited to a group of skilled experts. In this paper a feature-based framework for the automatic selection and sequencing of orientating devices is presented. A direct link between part representation and the selection and sequencing of modular orientating devices is provided by a spatial technique, in place of traditional CAD representation. Also described is the classification of a part's orientating features and classification of orientating devices. These two classifications are integrated into a knowledge-based system that will automatically generate sequences of modular orientating devices.

Cortisol triggers rapid but transient transcription of the silent vitellogenin (Vg) gene in male Oreochromis aureus, producing short-lived Vg mRNA. Implantation of cocoa butter containing cortisol at 0.8, 8, 20, and 40 micrograms/g fish body wt induced hepatic Vg mRNA within 1 or 2 hr. Implantation of cortisol at the lowest of these dosages (0.8 micrograms/g body wt) produced a transient surge in serum cortisol within 1 hr. This is equivalent to a 30-fold increase over that of the resting male fish in which the endogenous cortisol levels measured 10.5 +/- 2.39 and 11.4 +/- 3.1 ng/ml, respectively, for fish kept communally or singly. Although sham implantation with cocoa butter also resulted in the elevation of serum cortisol, the rise was much more gradual, only reaching a peak after 6 hr. Thus, parameters like the treatment regime, sampling time intervals after implantation, and the interaction between these two factors can significantly affect the serum cortisol concentrations (P = 0.001). Although implantation of cocoa butter with or without cortisol increased serum cortisol, albeit unsynchronized, Vg mRNA was detected only in the hormone-treated group. The profile of Vg mRNA accumulation appeared to coincide with that of serum cortisol, further suggesting the activating effect of exogenous cortisol on Vg gene. Compared with an earlier study on estradiol-induced Vg gene expression, the action of cortisol was more rapid, but transient. This is reflected in the rapid clearance of the cortisol-induced Vg mRNA and, hence, the lack of plasma Vg protein during cortisol treatment.

The dorsal fin of the larval and juvenile Oreochromis mossambicus exhibits a unique black spot known as the ‘Tilapia mark’. We traced its development and found that it occupied a specific position in the dorsal fin bounded by rays 15 and 20. Ablation experiments carried out on the larval dorsal fin showed that this spot region constituted a developmental positional field. This positional field in the fin could regenerate and re-establish the spot pattern despite repeated perturbation. The re-establishment of spot was not simply due to fin injury since ablation of the non-spotted region of the dorsal and the tail fin did not result in aggregation of melanophores. We propose that that‘Tilapia mark’ is a result of positional information in operation.