Breathing difficulty and tinnitus among children exposed to airbag deployment

OBJECTIVE: To assess the incidence of breathing difficulty and tinnitus in children involved in motor vehicle crashes with and without passenger airbag (PAB) deployment, and its relationship to seating position and to whether the airbag deployed was first versus second-generation. METHODS: We studied motor vehicle crashes with child passengers, over a 3-year period, in three large regions of the United States, by means of telephone interviews with the driver/parent. The crashes were classified into those with and without a PAB deployment. Complete data were collected on 7383 children in 4817 crashes, who, because of the sample design of the study, represent an estimated 120,987 children in 83,267 crashes. RESULTS: Among children involved in crashes with PAB deployment, 6.6% complained of breathing difficulty versus 1.4% without airbag deployment (OR 5.2, 95% CI 3.3-8.2). The corresponding figures for tinnitus were 5.0% versus 0.7% (OR 7.4, 95% CI 4.0-13.7). Analysis of data for children exposed to PABs indicated that 14.1% of children in the front seat versus 1.1% in the rear complained of tinnitus (OR 14.4, 95% CI 5.9-34.7). Seating row did not significantly affect the incidence of breathing difficulty. The type of airbag deployed did not significantly affect the incidence of breathing difficulty or of tinnitus. CONCLUSION: Breathing difficulty and tinnitus were much more common among children in crashes with PAB deployment as against those without PAB deployment. Among children in crashes with PAB deployment, tinnitus was about 14 times more likely for those sitting in the front versus rear seat. The incidence of breathing difficulty was not affected significantly by seating row. Introduction of second-generation airbags has not affected the incidence of breathing difficulty or of tinnitus.     

Optimization of process parameters of boro-carburized low carbon steel for tensile strength by Taquchi method with grey relational analysis

The results of study on the boro-carburizing and boronizing of AISI 1015 steel on tensile strength was carried out by Taquchi-grey relational method. The orthogonal array L₉(3⁴) was used to conduct the experiment. The thickness of boride layer increased with increase in process temperature and time. The thickness of boride layers for boronized AISI 1015 steel was more than the pre-carburized and boronized AISI 1015 steel. The microhardness decreased with increase in distance from the surface to the core. However, the hardness gradient reduced gradually from the surface to the core in case of boro-carburized treatments compared to boronized treatments. The optimal process parameters and their levels for pre-carburized AISI 1015 steel are carbon content 0.45% at 950 °C temperature and 4 h process duration. The results revealed that process time, case carbon content and process temperature influenced the yield strength and % elongation. The ultimate strength is influenced by the process temperature, process time and carbon content. The process temperature was the most influential control factor that affects the tensile strength properties.     

Experimental Results for Slow-speed Timing Characterization of High-speed Pipelined Datapaths

This article presents experimental results for a clock-timing methodology that allows timing characterization and testing of high-speed pipelined datapaths using slow-speed testers. The technique uses a clock-timing circuit to control the data flow in the pipeline in the test mode. Test results show that the design provides an average timing resolution of 52.9 ps in 0.18 μm CMOS technology. Results also demonstrate the ability of the technique to track the performance of high-speed pipelines at a reduced clock frequency and to test the clock-timing circuit used to generate and control test mode clocks.     

Fifteen observations on the structure of energy-minimizing gaits in many simple biped models

A popular hypothesis regarding legged locomotion is that humans and other large animals walk and run in a manner that minimizes the metabolic energy expenditure for locomotion. Here, using numerical optimization and supporting analytical arguments, I obtain the energy-minimizing gaits of many different simple biped models. I consider bipeds with point-mass bodies and massless legs, with or without a knee, with or without a springy tendon in series with the leg muscle and minimizing one of many different ‘metabolic cost’ models—correlated with muscle work, muscle force raised to some power, the Minetti–Alexander quasi-steady approximation to empirical muscle metabolic rate (from heat and ATPase activity), a new cost function called the ‘generalized work cost’ C_g having some positivity and convexity properties (and includes the Minetti–Alexander cost and the work cost as special cases), and generalizations thereof. For many of these models, walking-like gaits are optimal at low speeds and running-like gaits at higher speeds, so a gait transition is optimal. Minimizing the generalized work cost C_g appears mostly indistinguishable from minimizing muscle work for all the models. Inverted pendulum walking and impulsive running gaits minimize the work cost, generalized work costs C_g and a few other costs for the springless bipeds; in particular, a knee-torque-squared cost, appropriate as a simplified model for electric motor power for a kneed robot biped. Many optimal gaits had symmetry properties; for instance, the left stance phase was identical to the right stance phases. Muscle force–velocity relations and legs with masses have predictable qualitative effects, if any, on the optima. For bipeds with compliant tendons, the muscle work-minimizing strategies have close to zero muscle work (isometric muscles), with the springs performing all the leg work. These zero work gaits also minimize the generalized work costs C_g with substantial additive force or force rate costs, indicating that a running animal''s metabolic cost could be dominated by the cost of producing isometric force, even though performing muscle work is usually expensive. I also catalogue the many differences between the optimal gaits of the various models. These differences contain information that might help us develop models that better predict locomotion data. In particular, for some biologically plausible cost functions, the presence or absence of springs in series with muscles has a large effect on both the coordination strategy and the absolute cost; the absence of springs results in more impulsive (collisional) optimal gaits and the presence of springs leads to more compliant optimal gaits. Most results are obtained for specific speed and stride length combinations close to preferred human behaviour, but limited numerical experiments show that some qualitative results extend to other speed-stride length combinations as well.     

A polymer photodiode using vapour-phase polymerized PEDOT as an anode

We report the photovoltaic properties of devices made using a highly conducting polymer electrode, from vapour-phase polymerized poly (3,4-ethylenedioxy) thiophene (VPP PEDOT) on glass substrate as an anode and a polyfluorene copolymer poly[2,7-(9,9-dioctyl-fluorene)-alt-5,5-(4′,7′-di-2thienyl-2′,1′3′-benzothiadiazole)] (APFO-3) mixed with [6,6]-phenyl-C₆₁-butyric acid methylester (PCBM) in the ratio of 1:4 as the active layer. The device performance was compared with that of devices made with PEDOT-PSS on glass substrates. The surfaces of VPP PEDOT were imaged using atomic force microscopy (AFM).     

A Rate Independent Cohesive Zone Model for Modeling Failure in Quasi-Brittle Materials

Computational modeling of failure in quasi-brittle materials at various length scales is important. In this work we present a rate independent cohesive zone model for modeling failure in quasi-brittle materials. The proposed model can simulate cracking, slipping, and crushing of planes through a traction-separation law. A single surface hyperbolic failure criterion, which naturally comes as a direct extension of Coulomb friction criterion with cut-off in tension and cap-off in compression, has been developed. A Euler backward integration scheme together with a global-local Newton solver compatible with a substepping strategy has been used in numerical computations. The proposed model is then used for modeling of shear wall panels. The numerical results obtained are validated by comparing them with experimental results available in literatures.     

One‐Pot Synthesis of 2‐Arylquinazolines and Tetracyclic Isoindolo[1,2‐a]quinazolines via Cyanation Followed by Rearrangement of ortho‐Substituted 2‐Halo‐N‐arylbenzamides

The one‐pot synthesis of substituted 2‐arylquinazoline derivatives and tetracylic isoindolo[1,2‐a]quinazoline via cyanation followed by rearrangement of ortho‐substituted 2‐halo‐N‐arylbenzamides is described. Using dimethyl sulfoxide (DMSO) as the solvent, the cleavage of the tetracyclic isoindole fused quinazoline leads to the formation of 2‐arylquinazoline derivatives. When 1,4‐dioxane is used as the solvent, tetracyclic isoindole fused quinazolines are produced in good yield. A wide range of products, including 2‐phenylquinazolin‐4‐amine, 4‐methyl‐2‐phenylquinazoline and long‐chain 2‐phenyl‐4‐styrylquinazoline derivatives were produced in moderate to good yields using DMSO as the solvent. However, various tetracyclic isoindole fused quinazoline derivatives were obtained in good yields when 1,4‐dioxane was used as the solvent.

     

Influence of Mn doping on structural,electrical and magnetic properties of (0.90)BiFeO3–(0.10)BaTiO3 composite

Structural, electrical and magnetic properties of chemically synthesized polycrystalline Mn doped (0.90)BiFeO₃–(0.10)BaTiO₃ composites [(0.90)BiFe_1?xMn_xO₃–(0.10)BaTiO₃ (x = 0.0, 0.03, 0.05 and 0.10)] were studied. The dielectric constant was observed to decrease when frequency was increased from 20 Hz to 1 MHz and increased with the increase in temperature from 313 to 773 K. An interesting correlation between the antiferromagnetic Neel temperature (T_N) of bismuth ferrite and temperature dependent dielectric constant was observed. The calculated values of activation energies were in the order of 0.25–0.74 eV (<1.0 eV) and decreases with an increase of Mn concentration. The variation of a.c. conductivity obeyed the Jonscher’s power law (σ _ac  ∝ ω ^s ). The observed value of exponent‘s’ were in the range 0.09 < ‘s’ < 0.78 (<1.0) for all the sample at temperature ranging from 473 to 598 K. There was a systematic increase in the value of spontaneous magnetization on increasing Mn concentration.