A proximate method for determining the refractive indices of liquids

A simple method for measuring the refractive index of liquids that fill thin-wall cylindrical cells of any diameter is described. The method is based on the light-refraction phenomenon in cylindrical lenses and is implemented using a system of lines that are regularly positioned in a plane and are observed in monochromatic light through a liquid-filled cylinder. Images of lines are turned relative to the initial orientation, and the rotation angle is unambiguously related to the refractive index of the liquid.     

Coherent fluctuation nephelometry: A high-sensitivity method for detecting particles in liquids

A new method for detecting micron and submicron particles in liquids by measuring the intensity fluctuations of coherent radiation scattered from these particles is described and compared to available techniques. It is shown that this method allows the record-breaking detection sensitivities of 10³–10⁴ particles/ml to be attained at a simple design of the analyzer.     

传动元件的有控点共轭啮合运动几何测量法

一、概述就传动元件几何形状精度的评定观点及相应的测量方法和原理而言 ,其测量法大体可分为三类。1 .几何坐标测量法这种测量法的基点在于被测件是一个几何实体。建立一个基准测量坐标系 ,将被测工件 (它有自身的坐标系 )放置在该测量坐标系中去进行度量。按照工件坐标系和测量坐标系的关系 ,测量出该工件上被检测轮廓形状 (点、线、面 )和理论虚拟几何体上相应处轮廓形状 (点、线、面 )的差异 ,它可归结为测量对应点坐标位置的差异 ,即测量头与被测传动元件之间为点接触 ,所测量的误差数值 ,为被测工件表面实际轮廓上对应该检测点的轮廓…     

A method for evaluating optical properties of electrostatic systems

Equations for evaluating paraxial properties, first-order chromatic, and third-order geometrical aberrations of electrostatic optics systems composed of round lenses and cosine-distributed deflectors are derived. Some comments on electrode design are made.     

A compensation electrothermograph for liquids and gases

A follow-up system of an electrothermograph intended for conducting physicochemical studies of processes, such as boiling, in liquids and gases is described. A new bridge device, in which a common-mode signal that unbalances the bridge does not appear, is used in the instrument. The advantages of the follow-up systems built according the scheme proposed are shown. The measurement technique and the main metrological characteristics of the instrument are described. An example of actual studies of a superintense nucleate-boiling regime is given.     

A method for measuring the inertia properties of rigid bodies

A method for the measurement of the inertia properties of rigid bodies is presented. Given a rigid body and its mass, the method allows to measure (identify) the centre of gravity location and the inertia tensor during a single test. The proposed technique is based on the analysis of the free motion of a multi-cable pendulum to which the body under consideration is connected. The motion of the pendulum and the forces acting on the system are recorded and the inertia properties are identified by means of a proper mathematical procedure based on a least square estimation. After the body is positioned on the test rig, the full identification procedure takes less than 10 min. The natural frequencies of the pendulum and the accelerations involved are quite low, making this method suitable for many practical applications. In this paper, the proposed method is described and two test rigs are presented: the first is developed for bodies up to 3500 kg and the second for bodies up to 400 kg. A validation of the measurement method is performed with satisfactory results. The test rig holds a third part quality certificate according to an ISO 9001 standard and could be scaled up to measure the inertia properties of huge bodies, such as trucks, airplanes or even ships.     

A reliable method of preparing undecalcified human bone biopsies for electron microscopic investigation

Undecalcified preparation of bone tissue for electron microscopic investigation depends on an adequate embedding method. A low viscosity resin proved to comply with the particular conditions as there is good infiltration of specimen by the monomer medium and also sufficient hardness of the polymerization product. Both properties stabilize the transition of soft tissue to mineralized bone surface; thus reproducible results of good quality are obtained in ultra-thin sectioning. A special preparation technique of human bone biopsies for simultaneous light and electron microscopic investigation has been developed. The method is based on experiences with approximately 300 iliac crest biopsies in metabolic and endocrine bone disorders.     

Registration of rheological properties of liquids by electromagnetic levitation

The presented paper is focused on possibilities of research of rheological properties of liquids with use of the device based on the principle of electromagnetic levitation. The device works on the principle of damping of the levitated body vibrations by the liquid. Levitation is ensured by feedback control of the magnetic field using an optical barrier. Vibrations are excited by controlled interruptions of electromagnetic field. Thanks to this principle it is possible to investigate the liquid of non-Newtonian character, as well as liquids susceptible to clinging on spindles of rotational viscometers. The equipment was calibrated using silicate oil standards and its performance was compared with commercially used models of viscometers Anton Paar FRS1600 (viscosity range 3 mPa s–20 Pa s, precision 0.5%, temperature range 300–1600°C) and Brookfield DV-III Ultra (viscosity range 1.4 mPa s–20 Pa s, precision 1%, temperature range 100–1600°C).     

Preparation of functional ionic liquids and tribological investigation of their ultra-thin films

Novel ionic liquid materials based on 1-alkyl-4-[5-(alkylsulfanyl)-1,3,4-oxadiazol-2-yl] pyridinium tetrafluoroborate derivatives were synthesized. Ultra-thin ionic liquid films were prepared on silicon wafers by means of spin-coating and their tribological properties were investigated. The wear life increases when the chain length decreases. Under low load, they show good tribological properties which are closely related to the interaction between ionic liquid and substrate surface, especially the film of 1-ethyl-4-[5-(ethylsulfanyl)-1,3,4-oxadiazol-2-yl] pyridinium tetrafluoroborate, it has low friction coefficient and long wear life. So, this kind of ionic liquid can be potentially applied as ultra-thin lubricating coating.     

Thermo-oxidative stability and corrosion properties of ammonium based ionic liquids

Ionic liquids (ILs) as a novel and potential type of lubricants possess partly superior properties over traditional classes of lubricants. Their extremely low vapor pressure, generally high thermal stability and non-flammability suggest them for high performance applications. However, their tendency towards corrosiveness is neglected in general. The selection of three ILs was based on the aim to achieve relevant lubricant properties, in particular high oxidation stability and low corrosiveness, as well as high environmental benignity. The cations were in all cases ammonium based with and without functionalization. Bis(trifluoromethylsulfonyl)imide (NTF₂) was chosen as anion and has been replaced for one IL by methanesulfonate. Artificial aging was carried out to obtain knowledge about the lubricant long-term performance under both oxidative and humid conditions while being in contact with CuSn8P and 100Cr6 commonly used in tribology. For the evaluation of IL corrosion potential, the metal content in the IL was monitored by ICP-OES, metal specimens were examined optically and by SEM-EDX analysis. To find out the IL suitability for the long-term applications the thermo-oxidative stability of the IL has been analyzed by several mass spectrometric techniques. In this study, NTF₂ based IL - regardless of the cationic moiety - showed superior performance over methanesulfonate based IL under all conditions. In the case of 100Cr6, dry conditions lead to the lowest corrosion whereas CuSn8P caused the lowest corrosion under humid conditions. The degradation process based on thermally induced transmethylation of the IL investigated occurred only at the cationic moiety of methanesulfonate based IL This is based on mass spectrometric investigations and indicates a contribution to the enhanced corrosiveness by means of the IL reduced stability.     

Experimental and numerical investigation of modal properties for liquid-containing structures

The dynamic response of liquid-containing structures is governed by their modal properties, which are affected by the mass of liquid and other fluid-structure interaction mechanisms. Therefore, knowledge of the effects of different parameters on modal properties is helpful in conducting a precise dynamic response analysis. In this paper, the effects of liquid on the modal properties of two structures, i.e., a pipe structure and a cylindrical storage tank, are investigated experimentally. The experimental results are then used to construct accurate analytical/numerical models for these structures. The models are capable of regenerating the experimental dynamic characteristics of the structures with an acceptable accuracy, indicating a proper modeling of the effects of liquid and the corresponding interaction mechanisms.     

Laser flash method for measuring thermal conductivity of liquids-application to low thermal conductivity liquids

A laser flash method developed for the measurement of thermal conductivity of solids was applied to liquids of low thermal conductivity. The sample liquid was sandwiched in between a small thin metal disk and a sample holder. When the laser beam is absorbed in the front surface of the metal disk, the temperature of the disk quickly rises about 2 K and heat then flows downwards through the sample liquid as one-dimensional heat flow. The thermal conductivity of liquid can be obtained from the temperature fall of the disk without employing any reference materials and also without measuring the thickness of the sample liquid layer. Thermal conductivities of water and toluene near room temperature were measured by this method with a mean deviation of 2.6%. This laser flash method may be applied to the measurement of the thermal conductivity of liquids such as molten salts at elevated temperatures.     

An automated technique for identifying and measuring activities of short-lived radionuclides

An automated measuring system capable of determining decay constants and activities of radionuclides in a sample is described. The technique used in it is aimed at identifying radionuclides produced in a sample under fast-neutron irradiation. The advantage of this technique is the procedure for measuring the time dependence of the activity decay after the end of irradiation, which provides a means for acquiring the maximum statistics at a fixed detection efficiency by minimizing pauses between measurements. The developed technique has been tested by calibrating the monitor of neutron fluxes from the HΓ-150 neutron generator. A copper foil with a high chemical purity and a natural isotopic composition has been used as a test sample (an activation detector).     

A waveguide method for the investigation of the elastic wave action on a newly formed crack

A technique for studying the processes of mechanical action on a newly formed crack and a device with a movable waveguide used to form fixed cracks in a rock sample in laboratory conditions are described. Analyzing the features of acoustic pulses, one can relate them to the dimensions and rate of the crack propagation, as well as control the sample destruction process. Characteristic time intervals in the sample destruction process are observed and resolved. Experimental results on the destruction of a marble plate with the use of the waveguide method are presented.     

Simple method for the preparation of inp based samples for TEM investigation

A novel, rapid, and simple method is described for the preparation of InP based samples for investigation by transmission electron microscopy (TEM). The key feature of the technique is Ar⁺ ion bombardment in an iodine ambient. Cross sectional micrographs of Au/InP samples are shown as an example. The technique developed produces a large area of transparent region.     

A method for the evaluation of the boundary lubricating properties of aviation turbine fuels

Using the principle of the Amsler machine, a method has been developed for evaluating the boundary lubricating properties (lubricity) of aviation turbine fuels over a temperature range from ambient to 150°C in a controlled atmosphere. The method of fuel supply was found to be a critical factor, a single-pass flooded system being superior to both trickle feed and static flooded arrangements. Equally important were the hardness and surface finish of the test specimens. Fuel lubricity properties were quantified using a derived failure load based on coefficient of friction, a parameter which, for aviation turbine fuels, accurately reflected the lubrication conditions at the rubbing contact. Failure loads based on wear and gross seizure were less satisfactory. The correlation of friction failure loads with practical experience in the field was excellent for a wide selection of Jet A-1 type fuels including low lubricity fuel with added lubricity-improving boundary lubricating additive. The method is recommended for measuring the lubricity performance of candidate lubricity-improving additives, for monitoring low lubricity fluids used in hardware development and for investigating lubricity problems as they occur in practice.     

Disc machine investigation of thin oil films: A lubricant testing method

Disc machine tests are becoming recognized as useful and reliable for predicting EP lubricant performance. Test conditions may be chosen to simulate those in practice.A simple testing procedure is described that has been developed to meet the need of evaluating EP properties in oil formulation studies.Due to the temperature being the most important cause of lubrication failure, kinematic conditions of both discs, which strongly influence flash temperature and heat flow as well as EHD lubrication effectiveness, were assumed as variable test parameters and a wider oil screening criterion has been proposed.Preliminary test results are reported.