Design of precision measurement system for metallic hole

For most of the high-speed hole diameter measuring process, a contact measuring method is undesirable due to its slow and destructive touching process. Thus, an optical method is usually chosen for non-contact measurement. Unfortunately, for most holes in precise manufacturing, especially those with a high aspect ratio, the optical method cannot be used. In our study, we developed a simple and low-cost precision capacitive hole measuring system. By using a simple alignment mechanism, we prove that a high-resolution hole diameter can be achieved. Comparing a traditional measuring method like coordinate measuring machine with our system, over 99% correlation is easily obtained. The paper also presents a multilayer hole measuring probe and sensor probe for non-through-hole measurement.     

Analysis of Piled Raft Foundations Using a Variational Approach

A variational approach for the analysis of piled raft foundations is presented. The raft and piles are both analyzed by the use of the principle of minimum potential energy. By representing the deformation of the piles and raft using finite series, the method is very efficient for the analysis of a piled raft with a large number of piles. Comparisons with other numerical methods and field measurements have shown reasonable agreement.     

Characterization of the ion channels formed by poliovirus in planar lipid membranes

The steps in poliovirus infection leading to viral entry and uncoating are not well understood. Current evidence suggests that the virus first binds to a plasma membrane-bound receptor present in viable cells, leading to a conformational rearrangement of the viral proteins such that the virus crosses the membrane and releases the genomic RNA. The studies described in this report were undertaken to determine if poliovirus (160S) as well as one of the subviral particles (135S) could interact with membranes lacking poliovirus receptors in an effort to begin to understand the process of uncoating of the virus. We report that both forms of viral particles, 160S and 135S, interact with lipid membranes and induce the formation of ion-permeable channels in a manner that does not require acid pH. The channels induced by the viral particles 160S have a voltage-dependent conductance which depends on the ionic composition of the medium. Our findings raise the possibility that viral entry into cells may be mediated by direct interaction of viral surface proteins with membrane lipids.     

Achieving multimedia communications on a heterogeneous network

A heterogeneous intelligent network has been designed and implemented to allow multimedia real-time communications and messaging among local area network workstations with logically associated speakerphones and among ISDN voice/data terminals with transparent tablets on top of bitmap screens and stylus pens. The architecture, presentation, editing, storage, and retrieval of multimedia documents in these two different kinds of terminals are described. The messages and protocol conversion facilities used for multimedia communications are presented, as are the lessons learned in internetworking a local area network with ISDN     

A carbon fiber-based radiation sensor for dosimetric measurement in radiotherapy

A prototype sensor was designed and fabricated to explore the application of carbon fibers for absorbed dose measurements in the ionizing radiation field used for therapeutic radiology. The carbon fiber-based sensor has a 1.8 × 1.8 cm² sensing area. Both 6 and 15 MV X-ray beams produced by a Varian Clinac 21 EX medical linear accelerator were used to test the sensor. Radiation dosimetric measurements were performed by varying the dose rates, total dose, and field sizes to characterize various properties of the sensor. For the given dose range from 0 to 600 monitor units, the sensor displayed an excellent linear response. This sensor can be used for dosimetric measurements and real-time dose rate monitoring. Compared to existing MV X-ray measurement technologies in radiotherapy, this prototype sensor provides many advantages over commercially available dosimeters: (i) ease of operation; (ii) low noise at room temperature; (iii) light in mass; (iv) low voltage requirements; (v) potential for miniaturization; and (vi) real-time signal measurement. A higher spatial resolution can be achieved by miniaturizing the physical size of the current sensor design.     

Numerical and experimental investigation of preform design in non-axisymmetric warm forming

This paper describes a numerical and experimental investigation of preform design in non-axisymmetric warm forming in order to achieve a large reduction in the volume of flash. A titanium TA2 watch-case-like component was used as an example. Sixteen different shapes of hollow preforms were specially designed for finite-element simulation. Their diameters of the center-holes were designed based on the values of the diameters of end-face configurations of punches and ejectors. The corresponding thicknesses of the preforms were determined by the assumption of constant volume. Under the same processing conditions, the diameter of center-hole of the preform should be the inner diameter of ejector such that its volume of flash was able to be greatly reduced to 6% of the volume of the formed component whereas the volume of flash was approximately 25% in the conventional implementation. Experiments were subsequently performed to verify the simulation results. This study rationally demonstrates the success of the preform design for warm forming of non-axisymmetric components, and provides great improvement in the utilization of material in the bulk forming process. Thus, the achievement is a tremendous saving in materials, more than a fourfold, particularly for these rare and expensive alloys.     

Proposed Fire Safety Ranking System EB-FSRS for Existing High-Rise Nonresidential Buildings in Hong Kong

A Fire Safety Ranking System (EB-FSRS) is proposed for assessing the fire safety provisions in existing high-rise nonresidential buildings in Hong Kong. The objective is to investigate how far the fire safety provisions in those existing buildings deviate from the expectation of new codes. Suitable fire safety management can then be worked out in the transition period, based on the scores. Local fire codes were reviewed first to decide what should be the attributes and their weightings. From the reviewing results, three groups of attributes were proposed in the EB-FSRS. These are the passive building construction, active fire protection systems (fire services installation), and key risk parameters, all following the local fire safety requirements. The concept is similar to those equivalent concepts on fire safety parameters of the National Fire Protection Association–Fire Safety Evaluation System (NFPA-FSES). But the EB-FSRS is not a “trade-off” exercise. Thirty-seven old high-rise buildings were rated by studying their architectural features, interior details, and fire safety provisions. Scores under EB-FSES and NFPA-FSES are also compared.     

Gluconeogenic dependence on ketogenesis in isolated sheep hepatocytes

Dependence of gluconeogenesis on beta-oxidation and ketogenesis from long-chain fatty acids was examined in isolated sheep hepatocytes. Hepatocytes were incubated with a combination of gluconeogenic precursors (2 mM pyruvate, 20 mM lactate, and 5 mM propionate) plus other fatty acids, in the presence and absence of tetradecylglycidic acid, an inhibitor of the carnitine palmitoyltransferase reaction. Palmitate oxidation to total acid-soluble metabolites or beta-hydroxybutyrate was markedly inhibited by the addition of tetradecylglycidic acid. In general, oxidation of palmitate to carbon dioxide was not altered by tetradecylglycidic acid. Glucose production was inhibited 28 to 50% in the presence of tetradecylglycidic acid. Addition of acetate and butyrate inhibited gluconeogenesis, but octanoate addition had a slight stimulatory effect. In the presence of tetradecylglycidic acid, butyrate, but not acetate, addition further reduced gluconeogenesis. In contrast, addition of octanoate in the presence of tetradecylglycidic acid restored gluconeogenic rates to control values. The results are consistent with observations in several nonruminant species and suggest that, as in those species, ruminant gluconeogenesis requires at least a basal rate of beta-oxidation and ketogenesis from long-chain fatty acids to support maximum gluconeogenic rates.