Investigation of flax fibre reinforced epoxy friction composites

The use of eco‐materials on the basis of natural fibre reinforced polymer composites has found its way to many applications. In the automobile sector, the use of such composites has long been established for applications in the car interior. The use of natural fibre reinforced composites for braking applications has however not been confirmed yet. In this study the use of flax fibres as a candidate reinforcement substitution for glass or even the carcinogenic asbestos fibres has been investigated. Typical frictional materials such as alumina, iron and brass particulates have been used together with graphite as a lubricant. Epoxy resin was used as the binding matrix. Results show frictional behaviours comparable with commercially available brake linings at acceptable wear rates.     

Superhard coatings of the (Zr-Ti-Si)N and (Ti-Hf-Si)N systems produced by vacuum-arc deposition from a separated flow

Multicomponent hard coatings based on nitrides of Si-doped transition metals have been produced by vacuum-arc deposition with the use of a RF generator and separation of an ion-plasma flux. Physico-mechanical and tribotechnical characteristics of coatings have been studied. The possibility of their use as efficient protective coatings has been shown.     

The use of scanning probe microscope with a diamond tip as a nanotechnological tool

Experimental results of the use of a scanning probe microscope having a nanometric resolution in surface machining have been considered. Specific features of the device are a tip of boron-doped diamond single crystal and electromagnetic system of measuring a nanointeraction between the tip and sample surface. Three-dimensional images of gold and silicon surfaces after nanocleaning and nanoscratching have been demonstrated. The possibilities to use diamond nanotools for making elements of nanoelectronics have been discussed.     

The Use of Diazo Film as a Film Badge Dosimeter

This investigation has involved the determination of the spectral response and calibration of diazo film for use as a film badge dosimeter. Aprototype film badge has been constructed and the range of the response of the film has been extended by the use of suitably calibrated attenuating filters.     

Holographic diffuser by use of a silver halide sensitized gelatin process

Diffusers play an important role in liquid crystal display (LCD) application as a beam-shaping device, a brightness homogenizer, a light-Scattering device, and an imaging screen. The transmittance and diffusing angle of the diffusers are the critical aspects for the applications to the LCD. The holographic diffusers by use of various processing methods have been investigated. The diffusing characteristics of different diffusing materials and processing methods have been evaluated and compared. The microstructures of holographic diffuse have been investigated by use of using scanning electron microscopy. The holographic diffusers by use of the silver halide sensitized gelatin (SHSG) method have the structural merits for the improvement of the quality of diffusers. The features of holographic diffuser were exceptional in terms of transmittance and diffusing angle. The replication method by use of the SHSG process can be directly used for the manufacturing of diffusers for the display application.     

Chick Chorioallantoic Membrane as an In Situ Biological Membrane for Pharmaceutical Formulation Development: A Review

The use of animals in research has always been a debatable issue. Over the past few decades, efforts have been made to reduce, replace, and refine experiments for ethical use of experimental animals. The use of chick chorioallantoic membrane (CAM) was one of the proposed alternatives to the Draize rabbit ocular irritation test with several advantages including simplicity, rapidity, sensitivity, ease of performance, and cost-effectiveness. The recent use of CAM in the development of pharmaceuticals and testing models to mimic human tissue, including drug transport across CAM, will be discussed in this review.     

Chick chorioallantoic membrane as an in situ biological membrane for pharmaceutical formulation development: a review

The use of animals in research has always been a debatable issue. Over the past few decades, efforts have been made to reduce, replace, and refine experiments for ethical use of experimental animals. The use of chick chorioallantoic membrane (CAM) was one of the proposed alternatives to the Draize rabbit ocular irritation test with several advantages including simplicity, rapidity, sensitivity, ease of performance, and cost-effectiveness. The recent use of CAM in the development of pharmaceuticals and testing models to mimic human tissue, including drug transport across CAM, will be discussed in this review.     

On Practical Use of the Concept of D-Optimality

The purpose of this article is to review the possibility of practical use of the concept of D-optimality in response surface design. Second order quasi-D-optimum designs on a cube have been built and their high efficiency proved. Using the computer, a number of different second order response surface designs, previously built, have been compared. It has been proved that the D-optimum concept, being more general than the rotatable one, can be used as the theoretical basis for building and comparing response surface designs in use.     

Measurement of scattering properties of individual particles with a scanning flow cytometer

A hydrofocusing head with an optical cuvette has been developed for the flow cytometer to generate complete scatter patterns of single particles at scattering angles ranging from 10° to 120°. The scatter signal has been measured as a function of the angle (a flying indicatrix) by the use of particle motion within a scanning system of the flow cytometer by the use of a single photomultiplier. Scattering data measured with the flow cytometer have been compared with those calculated from Mie theory for latex particles. A calculation algorithm has been used to estimate the size and the refractive index of spherical particles from the scattering data measured.     

Thermal model for a hybrid cryostat

To maximize the hold time of a 2 dm³ 4 K helium cryostat, a system has been designed and built which makes use of a closed cycle refrigerator for cooling the radiation shields. The optimization of this so-called hybrid cryostat has been simplified by the use of a thermal model. The properties of a number of models have been obtained from simulation runs. Comparison between simulation results and measurements on the real system has shown good agreement. The real system optimized from model results yields a hold time of 6 days.     

Analysis of the individual factors affecting mobile phone use while driving in France: socio-demographic characteristics, car and phone use in professional and private contexts

In France, as in many other countries, phoning while driving is legally restricted because of its negative impact on driving performance which increases accident risk. Nevertheless, it is still a frequently observed practice and one which has not been analyzed in detail. This study attempts to identify the profiles of those who use mobile phones while at the wheel and determine the forms taken by this use. A representative sample of 1973 French people was interviewed by phone on their driving practices and mobile phone use in everyday life and their mobile phone use while driving. Logistics regressions have been conducted to highlight the explanatory factors of phoning while driving. Strong differences between males and females have been shown. For the male population, age is the main explanatory factor of phoning while driving, followed by phone use for work-related reasons and extensive mobile phone use in everyday life. For females, high mileage and intensive use of mobile phone are the only two explanatory factors. We defined the intensive phone use at the wheel group as drivers who receive or send at least five or more calls per day while driving. There is no socio-demographic variable related to this practice. Car and phone uses in everyday life are the only explanatory factors for this intensive mobile use of the phone at the wheel.     

Mobile phone use while driving: A hybrid modeling approach

The analysis of the effects that mobile phone use produces while driving is a topic of great interest for the scientific community. There is consensus that using a mobile phone while driving increases the risk of exposure to traffic accidents. The purpose of this research is to evaluate the drivers’ behavior when they decide whether or not to use a mobile phone while driving. For that, a hybrid modeling approach that integrates a choice model with the latent variable “risk perception” was used. It was found that workers and individuals with the highest education level are more prone to use a mobile phone while driving than others. Also, “risk perception” is higher among individuals who have been previously fined and people who have been in an accident or almost been in an accident. It was also found that the tendency to use mobile phones while driving increases when the traffic speed reduces, but it decreases when the fine increases. Even though the urgency of the phone call is the most important explanatory variable in the choice model, the cost of the fine is an important attribute in order to control mobile phone use while driving.     

Finite element modeling and testing of a deformable carbon fiber reinforced polymer mirror

Thin-shelled composite mirrors have been recently proposed for use as deformable mirrors in optical systems. Large-diameter deformable composite mirrors can be used in the development of active optical zoom systems. We present the fabrication, testing, and modeling of a prototype 0.2 m diameter carbon fiber reinforced polymer mirror for use as a deformable mirror. In addition, three actuation techniques have been modeled and will be presented.     

Single-mode GaAs/AIGaAs W waveguides with a low propagation loss

We have designed a low-loss single-mode GaAs/AIGaAs optical waveguide with a symmetric five-layer heterostructure at the 1.31-μm wavelength by use of an effective-index method. Waveguides with a W-shaped refractive-index profile have been grown by use of a metallo-organic chemical vapor deposition technique and fabricated with a chemical wet-etching method. Propagation loss has been measured by use of the Fabry-Perot resonance method and a sequential-cleaving experiment. The measured loss is as low as 0.19 dB/cm for waveguides with 2.3-μm thickness and 4.3-μm width, which is comparable to the lowest-loss semiconductor waveguides yet reported. These waveguides could be used to make low-loss modulators for guided-wave devices.     

Identification and characterisation of thaumasite by XRPD techniques

X-ray powder diffraction (XRPD) data analysis techniques (full pattern fitting and Rietveld refinement) have been evaluated as a means of characterisation of thaumasite. For the first time, these XRPD methods, which employ the whole of the powder pattern rather than just a few reflections, have been used to study systems containing thaumasite. Structure refinement by Rietveld methods, using synchrotron data, produced a crystal structure model of thaumasite suitable for use in the analysis of thaumasite in cements. The use of these techniques in the analysis of cement systems containing thaumasite is discussed. An example of the use of Rietveld refinement in quantification of a sample containing thaumasite is given.     

Characterization of strength properties of thin polycrystalline silicon films for MEMS applications

The aim of this work is to characterize the strength properties of polycrystalline silicon (polysilicon) with the use of tensile and bending test specimens. The strength of thin polysilicon films with different geometry, size and stress concentrations has been measured and correlated with the effective size of the specimen and its stress distribution. The test results are evaluated using a probabilistic strength approach based on the weakest link theory with the use of STAU software. The use of statistic methods of strength prediction of polysilicon test structures with a complex geometry and loading based on test values for standard material tests specimen has been evaluated.     

Stepping-Motor-Driven Constant-Shear-Rate Rotating Viscometer

Despite the frequent use of stepping motors in robotics, automation, and a variety of precision instruments, they can hardly be found in rotational viscometers. This paper proposes the use of a stepping motor to drive a conventional constant-shear-rate laboratory rotational viscometer to avoid the use of velocity sensor and gearbox and, thus, simplify the instrument design. To investigate this driving technique, a commercial rotating viscometer has been adapted to be driven by a bipolar stepping motor, which is controlled via a personal computer. Special circuitry has been added to microstep the stepping motor at selectable step sizes and to condition the torque signal. Tests have been carried out using the prototype to produce flow curves for two standard Newtonian fluids (920 and 12560 mPa middot s, both at 25degC). The flow curves have been obtained by employing several distinct microstep sizes within the shear rate range of 50-500 s^-1 . The results indicate the feasibility of the proposed driving technique.     

Method of Physical Modeling and Its Potentialities

Based on the theory of modeling with the use of several models, it has been shown that all the known methods of investigation of this type satisfy the same requirements. The possibility of determining the sought results characterizing one phenomenon or another from the measured quantities of a phenomenon that has no common parameters with the phenomenon being investigated has been substantiated. Examples of the practical use of modeling are given.     

Exploring the performance of molecular rectifiers: limitations and factors affecting molecular rectification

There has been significant work investigating the use of molecules as nanoscale rectifiers in so-called "molecular electronics". However, less attention has been paid to optimizing the design parameters of molecular rectifiers or to their inherent limitations. Here we use a barrier tunneling model to examine the degree of rectification that can be achieved and to provide insight for the design and development of molecules with optimum rectification responses.     

包头市废旧雷弹的爆破销毁

近些年来 ,包头市收缴了战争年代留下的 5 2 6枚废旧军用雷弹。这些爆炸物品虽已失去使用价值 ,但它们的存在对人民的生命财产构成了极大的威胁。针对这些废旧雷弹的特点 ,采用爆破方法将它们销毁。本文论述了这些雷弹搬运、销毁过程中的安全措施及注意事项 ,从中获取了一些有益的经验。