Experimental Techniques For Study Research Articles

Experimental Study of Material Structure in the Processing of Ball Pins

The article presents a technique for experimental studies of microstructure of microsections during rolling of ball pins made of 38KHGNM and 40KH steels. Moreover, photographing was carried out in the pole and equatorial parts of the ball pin head, as well as at the cross-cut end. When analyzing the photographs of microsections, it was concluded that after the final rotary rolling, deformation grinding of the grains occurred in the structure of ball pins.

High-Resolution Numerical Simulation of Microfiltration of Oil-in-Water Emulsion Permeating through a Realistic Membrane Microporous Structure Generated by Focused Ion Beam Scanning Electron Microscopy Images.

Owing to the limitations of visualization techniques in experimental studies and low-resolution numerical models based on computational fluid dynamics (CFD), the detailed behavior of oil droplets during microfiltration is not well understood. Hence, a high-resolution CFD model based on an in-house direct numerical simulation (DNS) code was constructed in this study to analyze the detailed dynamics of an oil-in-water (O/W) emulsion using a microfiltration membrane. The realistic microporous structure of commercial ceramic microfiltration membranes (mullite and α-alumina membranes) was obtained using an image processing technique based on focused ion beam scanning electron microscopy (FIB-SEM). Numerical simulations of microfiltration of O/W emulsions on the membrane microstructure obtained by FIB-SEM were performed, and the effects of different parameters, including contact angle, transmembrane pressure, and membrane microporous structure, on filtration performance were studied. Droplet deformation had a strong impact on filtration behavior because coalesced droplets with diameters larger than the pore diameter permeated the membrane pores. The permeability, oil hold-up fraction inside the pores, and rejection were considerably influenced by the contact angle, while the transmembrane pressure had a little impact on the permeability and oil hold-up fraction. The membrane structure, especially the pore size distribution, also had a significant effect on the microfiltration behavior and performance.

ЭФФЕКТИВНОСТЬ АРМИРОВАНИЯ КАМЕННЫХ СВОДОВ КОМПОЗИТНЫМИ МАТЕРИАЛАМИ

The stone vaults of historical buildings are considered, which, due to a decrease in bearing capacity, require repair and restoration work. An analysis is given of the mechanisms of destruction of cylindrical vaults depending on the ratio of their height to the span. The advantages of strengthening the vaults with the help of reinforcement with composite materials are analyzed. A description is given of the technology of surface reinforcement of stone structures using composite materials on a polymer cement matrix FRCM (Fiber Reinforced Cementitious Matrix). The technique of experimental studies of models of reinforced and non-reinforced vaults is given. On the basis of the experiment, it is shown that the effectiveness of the reinforcement of the vaults is determined by the features of their stress-strain state and failure mechanisms. In particular, the effectiveness of reinforcement increases with an increase in the ratio of the height of the vaults to its span. These results are substantiated by the fact that in high arches the ratio of bending moments and longitudinal forces is dominant, and in the case of flat arches, longitudinal and transverse forces dominate in their sections, and destruction occurs in the form of shearing along inclined sections. Also, the effectiveness of reinforcement increases with their asymmetric loading relative to the middle of the span. According to the results of the study, graphs of the dependence of the maximum vertical displacements of the vaults were constructed, showing a significant effect of reinforcement on increasing their rigidity. In addition, it is emphasized that by now there is a need for a stable theory of the strength of complex stone structures - curvilinear, vaulted and others that are in a complex stress state. Its appearance can significantly simplify and unify the calculations made when examining stone buildings, drawing up projects for their restoration and reconstruction, and solve the problems of the strength of the masonry of modern facade systems.

Technique for experimental studies of asphalt concrete milling process

The paper considers the issues of destruction of the working bodies of road-building equipment operated under conditions of abrasive wear with a fixed abrasive. Analytical studies of the influence of the tribological parameters of cutters on the intensity of their wear have been carried out. Based on the solution of the equations of the dynamics of the movement of the cutter in a viscoelastic medium, its geometric shape is optimized. The mathematical dependences of the influence of the geometric dimensions of the cutter on the pressure value and the intensity of tool wear are obtained.

Results of experimental researches of reinforced concrete retaining walls

Relevance. Hydroelectric facilities include reinforced concrete retaining walls. They are intended to protect the main structures from the collapse and sliding of soil massifs. Retaining walls are characterized by significant size, relatively low content of reinforcement, the presence of horizontal interblock seams, which considerably affects the features of the work and the state of retaining walls. The normative documents that were in force during the design and construction of most retaining walls (the second half of the last century) did not fully take into account the features of the retaining walls, as a result of which long-term operation revealed deviations from the design premises, including excessive displacement of the top of the walls, the disclosure of horizontal interblock joints, which exceeded the design values. In a number of cases, reinforced concrete structures of retaining walls were reinforced in areas of interblock joints. The aim of the work is to conduct experimental studies of reinforced concrete retaining walls, including taking into account their reinforcement by inclined reinforcing bars. Methods. The technique of experimental studies of hydraulic engineering reinforced concrete structures was applied in accordance with regulatory documents and the developed program of experimental studies of reinforced concrete retaining walls. The results obtained showed the opening of horizontal interblock joints, the formation of inclined cracks emerging from the joints. An increase in the strength of reinforced concrete structures of retaining walls and a decrease in their deformability due to reinforcement by inclined rods in the area of the interblock weld were recorded.

Inferring What to Do (And What Not to)

In recent years, the “planning as inference” paradigm has become central to the study of behaviour. The advance offered by this is the formalisation of motivation as a prior belief about “how I am going to act”. This paper provides an overview of the factors that contribute to this prior. These are rooted in optimal experimental design, information theory, and statistical decision making. We unpack how these factors imply a functional architecture for motivated behaviour. This raises an important question: how can we put this architecture to work in the service of understanding observed neurobiological structure? To answer this question, we draw from established techniques in experimental studies of behaviour. Typically, these examine the influence of perturbations of the nervous system—which include pathological insults or optogenetic manipulations—to see their influence on behaviour. Here, we argue that the message passing that emerges from inferring what to do can be similarly perturbed. If a given perturbation elicits the same behaviours as a focal brain lesion, this provides a functional interpretation of empirical findings and an anatomical grounding for theoretical results. We highlight examples of this approach that influence different sorts of goal-directed behaviour, active learning, and decision making. Finally, we summarise their implications for the neuroanatomy of inferring what to do (and what not to).

Experimental Studies of Salt Transfer in Irrigation Systems

Experimental hydrogeochemical studies on water-balance areas in field and laboratory conditions are considered. The principles of the selection and equipment of water-balance areas and laboratory facilities, as well as the selection of the main pollutants and the chemical composition of indicator solutions and water for the washing of pillars and monoliths, are established. A sequence of experimental procedure in field and laboratory conditions is proposed. A method to determine the salt transfer parameters with the use of mathematical models of salt macrodispersion (three methods: reference curves, moments and graph-analytical), microdispersion, and dissolution is considered. The technique of experimental studies of salt transfer was tested on the northern Ershov irrigation system (NEIS) in the Saratov oblast.

Fine grained concrete structures reliability assessment: theory and investigational studies

Describes the theoretical preconditions of using mechanical properties of fine-grained concrete in the design of concrete structures subject to risks and the general safety. A technique for experimental studies and data on the fine-grained concrete deformative properties at different ages and different loading levels are presented. The regularities of the modulus of elasticity change from strength, type and age of concrete are revealed. Full diagrams of deformation of concrete are constructed. The results obtained can be used in the design of the fine-grained concrete structures in buildings having risks occurrence socioeconomic losses and able to resist of emergency actions.

Experimental Glaucoma-Related Structural Modifications in the Nerve Apparatus of the Rabbit Eye

We estimated morphometric characteristics of the neurooptic apparatus of the rabbit eye using optic coherent tomography. In animals with experimental glaucoma induced by course introductions of adrenaline, the thickness of the nerve fiber layer in the peripapillar zone of the retina was smaller than that in healthy rabbits. Changes in the nasal and temporal quadrants of the retina were most considerable (34 and 23% decrements, on average; P < 0.05). The area of the disc of the visual nerve in rabbits with glaucoma neuropathy was about 52% smaller than that in the norm (P < 0.05). Using modern visualization techniques in experimental studies allows researchers to characterize morphology of the eye nerve structures in vivo; this is important for estimation of the dynamics of the respective changes and development of methods of their correction.

Analysis of static errors of adaptive mirrors

A technique for experimental studies of the compensatory abilities of adaptive mirrors (AM) is developed and substantiated. The structure of the static residual error of correction is analyzed on the basis of experimental data for a particular AM. The theory of optimal placement of drives on the AM aperture is confirmed by experimental results.

Experimental study of syphon suntrap

A technique for experimental study of the syphon suntrap is described. The application of this suntrap allows rather simple provision of the consumer with the preassigned temperature without using circulation pumps or automation and control systems.

Mechanisms and species of gold incorporation into crystals of cadmium, lead, and iron sulfides

The mechanisms and species of gold incorporation into crystals of simple sulfides are described. The concept of endocrypty in its modern treatment and the corresponding technique of experimental study were used. The technique is based on the principle of phase composition correlation and variation of parameters specifying the concentrations of active crystal defects. Gold species are determined with the method of statistical samples of analytical data for single crystals (SSADSC). The highest gold incorporation limits have been established for PbS and CdS under high sulfur fugacity (2.4⋅10 −2 and 7⋅10 −3 wt.%, respectively) at 500 °C and 1 kbar. It is shown that in this case, the main crystal defects are metal (Me) vacancies and the gold species is a donor-acceptor pair “Me vacancy– interstitial Au”. Under low sulfur fugacity, Au incorporation might be due to sulfur vacancies, and the gold species is a pair “Au in the Me position–S vacancy”; its concentrations are lower than those at high sulfur fugacity (≤10 −3 wt.%). A specific feature of gold is a tendency to endocrypty. The estimated limiting contents of gold incorporated into sulfide crystals (FeS2, CdS, PbS) at 450–500 °C vary from n⋅10 −4 to n⋅10 −2 wt.%, which is nearly two orders of magnitude higher than the “true” isomorphous capacities of these crystals. For FeS, the incorporation limit of Au does not depend on defects (Fe vacancies). This phenomenon has not been explained yet. In general, the data obtained show that not only the crystallochemical features but also geochemical parameters (first of all, temperature and sulfur fugacity) of the ore formation medium are the main factors for gold concentration in sulfide minerals.

A culture technique for experimental studies of embryonic development in the pond snail Lymnaea stagnalis

Summary The gastropod mollusc Lymnaea stagnalis has long played an important role in strengthening our knowledge of developmental biology. However, experimental studies of this and related species have been limited because its embryos develop within egg capsules, which prevent the passage of large molecules and puncturing the capsules results in disrupted development and eventual death. Therefore, long-term experiments involving administration of substances, cell ablations or dye injections have been impossible. The present study explores conditions for culturing embryonic L. stagnalis outside the capsule. The most effective method consisted of raising embryos within capillary tubes and bathed in their natural capsule fluid. Additional experiments were also performed to test the extent to which the capsule fluid could be replaced with artificial media. Results revealed that certain artificial media could sustain prolonged survival of the embryos but that inclusion of a proportion of natural capsule fluid was essential for development to proceed past a mid-veliger stage. Therefore, a range of concentrations of the capsule fluid was tested and it was found that a minimum of 30% natural capsule fluid diluted with either an artificial culture medium or distilled water permitted normal development. These results suggest that the capsule fluid may contain a factor(s) which is required for normal development in this species. We also tested the possibility that such a factor is a growth factor. However, solutions of nerve growth factor (β-NGF), transforming growth factor (TGF-β1) and epidermal growth factor (EGF) were not sufficient to support embryonic development.

Experimental study of the first suckling episode: Rat pups ingest fluids through a surrogate nipple.

The present study reported a new technique in which pups ingested fluids from a surrogate nipple. Cesarean-delivered pups tested before suckling experience showed oral grasp responses and ingested milk from the surrogate nipple. Pups ingested equal amounts of distilled water and milk and rejected saline. After ingesting milk from the surrogate nipple, pups remained attached to an empty surrogate nipple, while pups exposed to distilled water or saline did not show sustained attachment. Brief experience with milk from an oral cannula or from a surrogate nipple elicited sustained attachment to an empty nipple. Pups ingesting milk from a surrogate nipple showed increased intake of water and saline from the nipple when tested subsequently. The surrogate nipple provides a new technique for experimental study of early suckling behavior. The results suggest that initial experiences with milk may reinforce components of early suckling behavior.

Summary and Future Research Needs

Dr. Bromberg: This is a remarkable meeting in that, with very few exceptions, almost no mention was made of pulmonary mechanics and of gas exchange. That doesn't happen very often in meetings devoted primarily to lung research, but perhaps has been happening more frequently in the recent past and it may indicate a trend for the future. Another interesting note was that almost everyone is working or collaborating with an ultrastructuralist, or would like to have access to ultrastructural techniques. Dr. Reid, among others, gave us a very nice demonstration of how ultrastructural techniques can be combined with biochemical techniques in experimental studies of the reaction of the lung to insults. Dr. Satir presented most elegant ultrastructural biochemical data on the mechanism of ciliary motion. The organization of the meeting, as I perceive it, looks at the lung as having three segments. There was a large area of attention to the epithelium, and at the end, there was a large area of attention to the endothelium. In the middle, I suppose appropriately, there were a number of speakers who talked about cells that more or less fit between the epithelium and the endothelium. Notably missing, or in large measure missing, were discussions of smooth muscle and of neural function at more than a passing level. The keynote of the epithelial sections was set by Dr. Boucher and Dr. Gatzy, who pointed to the barrier function of the epithelium and the attempts to quantitate the nature and the site of this barrier. They paid special attention to the intercellularjunctions and the so-called tight junctions of the epithelium and defined their properties by electrical measurements and by using a variety of non-charged probe molecules.

The kinetics of capillary absorption of liquids in a constant magnetic field

The method and technique of experimental study is described with respect to the kinetics of capillary absorption of distilled water and a 10% aqueous solution of NaCl by quartz sand in a nonuniform magnetic field. The results of this experimental study are given.