Simple Engineering Technique Research Articles

Software System SPDIAL

Spiroid gears are direct competitors to traditional technical solutions - worm and hypoid gears; and they have proven themselves in a large number of specific technical applications, providing greater strength, smaller size, and easier production. However, their design process is much less subject to being typical and standard and to resulting in simple engineering techniques. In fact, effective solutions can be obtained only by actually researching the space of parameters. An indispensable tool for this is a computer-aided design and research system. The paper presents the summary of such a system SPDIAL+ for worm-type gears (worm, QN-gears, spiroid) developed at Izhevsk scientific school in the field of gears and gearboxes. In particular, the possibilities of designing a conjugated gear, choice of gearwheel cutting parameters, analysis of gears under the action of errors and loads are considered. The role and results of applying the program as the main tool for research, design and innovations like new varieties of gears, their new properties in specific applications, new methods and techniques of tooth machining are shown.

Boosted device performance of perovskite solar cells via KI processing additives

AbstractPerovskite solar cells (PSCs) have attracted great attention in both academic and industrial sectors in the past years. Studies demonstrated that processing additive engineering was a facile way to improve the crystallinity and minimize the defect of metal halide perovskites (MHPs). In this study, we report efficient and stable PSCs, where the MHPs thin film is processed with KI additives. It is found that the KI processing additives could not only enhance the crystallization and suppress the defects of MHP thin film, but also boost charge transport, suppress non-radiative recombination, and enhance the hydrophobic properties of MHP thin film. As a result, the PSCs based on the MHPs thin film processed with KI additives exhibit more than 10% enhancement in efficiency and dramatically boosted stability compared to that based on pristine MHPs thin film. Our results indicated that the MHPs processed with processing additives are a simple engineering technique to boost the device performance of PSCs.

Analytical Model of Interaction of an Oil Pipeline with a Support of an Overpass Built in a Mountainous Area

Today, pipelines are the safest and most economical way to transport petroleum products and one of the key components of modern energy infrastructure. Nevertheless, pipeline systems are associated with certain risks that can lead to environmental disasters. The idea of carrying out this study was initiated by the results of the survey of the overpasses of the long-used oil pipelines laid in the mountainous area of the Carpathian region. Defects such as a change in the shape of the pipe and local bulges in the area of oil pipeline support nodes were detected. The explanation of the described problem is separate from the typical algorithms of design calculations, which are offered to manufacturers by current directive documents. The desire to provide an explanation and quantitative assessment of the detected defects became the main motivation for writing the article. An analytical model of the interaction of the oil pipeline with the rigid support has been developed. Additional internal loads in the cross-section of the pipe and displacement of its middle surface, which arise as a result of such interaction, are determined. The method of determining the reaction in the intermediate support of the overpass of the oil pipeline has been developed, considering the properties of the soil base in the underground sections and the mounting gap in the support node. The analytical dependence was obtained to determine the additional hoop stresses that arise in the oil pipeline due to the contact of the pipe with the support. The unambiguous relationship between the maximum additional hoop stress and the reaction in the support node was established. The dependence of additional hoop stresses on the geometric characteristics of the pipes was analyzed. The obtained research results are tested on the real structure of the overpass of the Druzhba oil pipeline, built in the Carpathians. In general, a simple engineering technique has been developed that allows analyzing the behavior of the oil pipeline support node and provides the numerical correction to the traditional strength assessment formulas, which determine the equivalent stresses in the oil pipeline.

Оцінка втомної міцності при асиметричному циклі навантаження

The object of study in the article is the individual parts of aircraft units, applied to loads that change over time. The subject of study is models that describe fatigue resistance under asymmetric loads. The goal is to develop a fairly simple engineering technique for detecting parts of aircraft units operating under an asymmetric loading cycle. Tasks: general analysis of many approaches to design cycles before the destruction of parts of aircraft units, production with an asymmetric loading cycle; select calculations acceptable for practical calculations, determine the endurance limit under a symmetrical loading cycle for steels and aluminum alloys used in aircraft units; select a calculation to calculate the maximum amount of asymmetric cycle. Methods used engineering analysis of methods for constructing a fatigue curve for an asymmetric speed change cycle; calculation of the endurance limit for a symmetrical cycle of change depending on the properties of materials based on the results of experimental selection and calculation of the endurance limit of materials to calculate the endurance limits of materials; the finite element method for counting and increasing dimensions in parts in the Simulation software package in Solidworks packages. The obtained results are obtained: an equation is chosen for the structure of the curve with an asymmetric cycle of stress change, given mechanical properties of the material; selections are selected for calculation with acceptable accuracy according to the specified properties of the endurance limits of materials with a symmetrical loading cycle of steels and aluminum alloys used in aircraft units; calculations were selected to calculate the limiting value of the asymmetric oscillation of the cycle; a method for determining the constants of the Weibull distribution for the fatigue curve under an asymmetric load cycle is proposed. Conclusion: an engineering technique has been developed for determining the resistance of parts of aircraft units operating under loads that change over time according to an asymmetric cycle.

TO THE PROBLEM OF MODELING THE AERODYNAMICS OF SURFACE TRANSPORTATION VEHICLES

The article deals with the problems of modeling the aerodynamics of surface high-speed vehicles of winged layout moving at a short distance from the water surface. To support them in the air, the screen effect formed under the influence of proximity to the water surface should be used. The effect of ground proximity is observed in air transport in the takeoff and landing modes of aircraft. The proximity of the ground affects the formation of the aerodynamic characteristics of vehicles. Today, the study of the aerodynamics of advanced vehicles moving near the underlying surface is possible using the following approaches: full-scale tests; modeling on special tracks; wind tunnel modeling. Full-scale tests are usually used at the final stages of vehicle development. simulation on special tracks is associated with the complexity of obtaining aerodynamic characteristics and is not widely used. The most suitable is modeling using wind tunnels. The current level of equipment of experimental laboratories allows for correct aerodynamic studies of aircraft. However, when modeling aerodynamic processes around vehicles moving near the interface, complex problems arise with reproducing the conditions of motion dynamics. The paper describes in detail the methods of studying the influence of the proximity of the ground on the formation of aerodynamic characteristics of vehicles in wind tunnels. These include: a method using a fixed plate; a method of mirroring the model; a method of suction or blowing the boundary layer; a method using a moving belt. The possibility of their use for modeling the aerodynamics of high-speed surface vehicles of winged layout is evaluated. When modeling the flow of high-speed vehicles moving near the water surface, a number of difficulties arise due to the realization of real flow conditions, namely, taking into account the dynamics of the water surface. Ideally, relative motion is realized between the vehicle and the water surface. The review of methods used in modeling the aerodynamics of vehicles over a solid screen proved to be of little use for high-speed winged vehicles moving at a short distance from the water surface. Ensuring the similarity of relative motion is an extremely difficult task. It requires a reasonable analysis of physical processes and the search for ways to develop physical and mathematical models suitable for use in the design of high-speed surface vehicles with wing arrangement. These models should range from simple engineering techniques to techniques based on the full and averaged Navier-Stokes equations.

Engineering method for calculating the operation modes of the heat supply station with the associated heat supply

The effective use of heat power in heat supply systems requires the development of new methods for central and local regulation of heat supply systems, the use of heat supply schemes with associated heat supply. The development of such technologies requires modeling and systematic calculations of variable modes of joint operation of local heat-consuming sys-tems. Currently used methods for calculating such operating modes of heat exchangers usually use constant parameters of heat exchangers. Such methods are not applicable in cases for large changes in temperatures and flow rates. Therefore, the calculation of variable modes of tied heat exchangers is usually performed by the method of successive approximations and is very time-consuming, which complicates the construction of a control system. In the present work, a fairly simple engineering technique is proposed for calculating the operating modes of heating stations of heat supply systems with associated heat supply. The basis of this technique is the use of previously derived analytical formulas that describe the change in the parameters of heat exchangers for various schemes of heating stations and temperature graphs of central regulation. The developed method allows the calculation of variable operating modes of the heat supply system without resorting to the method of successive approximations. The efficiency of the proposed methodology was tested on the operational data of the central heating station in the Kalinin district of Novosibirsk.

Coastal tectonics and habitat squeeze: response of a tidal lagoon to co-seismic sea-level change

We investigated the response of a tidal lagoon system to a unique situation of relative sea-level change induced by powerful earthquakes (up to Mw 7.1) on the east coast of New Zealand in 2010–2011. Spatiotemporal impacts were quantified using airborne light detection and ranging (LiDAR) datasets complemented by hydrodynamic modelling and evaluation of anthropogenic influences. Ground-level changes included examples of uplift and extensive subsidence (ca. 0.5 m) associated with intertidal area reductions, particularly in supratidal zones. ‘Coastal squeeze’ effects occurred where incompatible infrastructure prevented upland ecosystem movement with relative sea-level rise. Despite large-scale managed retreat, legacy effects of land-filling have reduced the reversibility of human modifications, impairing system resiliency through poor land-use design. Elsewhere, available space in the intertidal range shows that natural environment movement could be readily assisted by simple engineering techniques though is challenged by competing land-use demands. Quantification of gains and losses showed that lagoon expansion into previously defended areas is indeed required to sustain critical habitats, highlighting the importance of a whole-system view. Identifiable coastal planning principles include the need to assess trade-offs between natural and built environments in the design of hazard management plans, requiring greater attention to the natural movement of ecosystems and areas involved. Treating these observations as a scenario illustrates the mechanisms by which coastal squeeze effects may develop under global sea-level rise, but our purpose is to help avoid them by identifying appropriate human responses. We highlight the need for an improved focus on whole-system resilience, and the importance of disaster recovery processes for adaptation to climate change.

Geospatial Tools for Suitable Assessment of Small Holder Irrigation Water, towards Increased Food Production and Poverty Eradicationin Nigeria: A Case of Jos East LGA. Plateau State

Irrigation is very crucial for sustaining global food security and poverty reduction, especially during off season food production in developing countries. Plateau state in recent years is exploring extensive irrigation schemes to meet up overwhelming national demands of exotic temperate crops and vegetables. The local farmers relyon seasonal streams and abandoned mine ponds for irrigating their crops, but water in these sources are exhausted easily, leading to increased yield losses. This research explores geoinformation methods to map, select and quantify suitable areas to site reservoirs for sustainable Small Holder Irrigation in Jos East LGA of Plateau state as a case study. Spatial Multi Criteria Analysis (SMCA) and other quantitative tools were employed for the spatial modeling and subsequent analysis. The results revealed that 11 sites are highly suitable in Jos East. Volumetric analysis was carried out to estimate potential water collection capabilities of these reservoirs, and the water prospect is estimated between ~172,660 m3 to ~13,929,275 m3, this was based on the calculated depth, and surface area of the prospective reservoirs. Subsequently, this model can be replicated in other parts of Plateau state, Nigeria and Africa with similar environmental, climatic conditions and water demands. We propose small reservoirs with simple engineering techniques to serve poor local communities in developing countries, which can alleviate poverty and enhance sustainable agricultural production. The initiative is in line with FAO’s and World Bank’s programs and recommendations, and which can promote pragmatic solutions and guide project allocations in line with Sustainable Development Goals (SDGs).

Managing the processes accompanying fluid motion inside oil field converging-diverging pipes

In recent years, there is an increased interest in pipes with regularly variable section area (converging-diverging pipes) in the oil chemical industry. At the same time, there is no simple engineering technique for calculation of hydrodynamic characteristics of such devices, which significantly impedes computations for mass exchange processes inside them. Attempts to concentrate energy dissipation and their control near the phase boundary were mainly directed at using the fluid flow pulses induced by an external generator, alternating displacement field, pulses caused by fluid flow through the conduit with a variable cross-section. As a result, it has been revealed that the forces determined by action of convective acceleration are capable of causing a significant deformation and breakage of disperse inclusions (drops and bubbles). For rigid particles, the action of the convective acceleration leads to a periodic impulse renewal of liquid near the surface of the rigid particle.

Make it simple: long-term stable gradient generation in a microfluidic microdevice.

Microfluidics-based gradient generators have been used for various biological applications, specifically chemotaxis in cell culture. However, the ability to generate and maintain long term gradients alongside the ability to quickly switch solutions is a challenge of the current microfabricated systems. In this study, a simple flow-driven microfluidic system was developed to achieve long-term stable concentration gradients. Computational modelling was performed to highlight the fluid dynamics as well as to verify the ability of maintaining stable gradients over 7days. Numerical simulation was analysed to evaluate the static pressure, velocity magnitude and wall shear stress distribution in the chamber. A microdevice fabricated with polydimethylsiloxane (PDMS), using a standard soft lithography technique is presented. It consists of eight parallel microchannels (5μm × 30μm × 1,800μm) linking source and sink chambers; a syringe pump drives fluid through the sink chamber, advection/diffusion from source to sink establishes a gradient. A gradient of a fluorescent dye was generated under the low flow control at 1-10μl/h of a simple syringe pump equipped with a pulsation damper that was comparable to a pulseless microfluidic pump. Concentration gradients were formed in 1h and stable from 2h out to 5days and consuming less than 1.0ml of solution. This study focuses on a novel solution to achieve a long-term microfluidic gradient generator using simple engineering techniques of biomedical microdevices.

Tissue Engineering the Cornea: The Evolution of RAFT.

Corneal blindness affects over 10 million people worldwide and current treatment strategies often involve replacement of the defective layer with healthy tissue. Due to a worldwide donor cornea shortage and the absence of suitable biological scaffolds, recent research has focused on the development of tissue engineering techniques to create alternative therapies. This review will detail how we have refined the simple engineering technique of plastic compression of collagen to a process we now call Real Architecture for 3D Tissues (RAFT). The RAFT production process has been standardised, and steps have been taken to consider Good Manufacturing Practice compliance. The evolution of this process has allowed us to create biomimetic epithelial and endothelial tissue equivalents suitable for transplantation and ideal for studying cell-cell interactions in vitro.

A Simple Engineering Technique to Improve Transesterification for Biodiesel Fuel Production

A Simple Engineering Technique to Improve Transesterification for Biodiesel Fuel Production

Flexural layered deformational model of reinforced concrete members

Based on a method recently proposed by the author and his co-workers, new average-stress/average-strain relations of cracked tensile concrete have been derived from experimental moment–curvature diagrams of under-reinforced concrete beams reported in the literature. Using these and previously obtained relations, a new constitutive relationship of cracked tensile concrete has been proposed for short-term deformational analysis of flexural reinforced concrete members. The stress–strain relationship, called the Flexural, accumulates tension-softening and tension-stiffening effects. A quantitative dependence has been established between the length of the descending branch and the reinforcement ratio. The Flexural constitutive relationship has been applied in a simple engineering technique based on a layered approach and the principles of strength of materials. To assess the accuracy of the technique, deflections/curvatures have been calculated for a large number of experimental reinforced concrete beams reported in the literature. Comparison has been carried out with well-known constitutive relationships and design code methods such as the ACI, EC2 and SNiP (Russian code).

Flexural layered deformational model of reinforced concrete members

Based on a method recently proposed by the author and his co-workers, new average-stress/average-strain relations of cracked tensile concrete have been derived from experimental moment–curvature diagrams of under-reinforced concrete beams reported in the literature. Using these and previously obtained relations, a new constitutive relationship of cracked tensile concrete has been proposed for short-term deformational analysis of flexural reinforced concrete members. The stress–strain relationship, called the Flexural, accumulates tension-softening and tension-stiffening effects. A quantitative dependence has been established between the length of the descending branch and the reinforcement ratio. The Flexural constitutive relationship has been applied in a simple engineering technique based on a layered approach and the principles of strength of materials. To assess the accuracy of the technique, deflections/curvatures have been calculated for a large number of experimental reinforced concrete beams reported in the literature. Comparison has been carried out with well-known constitutive relationships and design code methods such as the ACI, EC2 and SNiP (Russian code).

SHORT-TERM DEFORMATIONAL ANALYSIS OF PRESTRESSED CONCRETE BEAMS USING FLEXURAL CONSTITUTIVE MODEL

In this paper, an attempt has been made to extend application of the recently proposed Flexural constitutive model to short-term deformational analysis of flexural prestressed concrete members. The relationship of tensile concrete is based on smeared crack approach and accumulates cracking and the tension stiffening effects. The Flexural constitutive model was applied in a simple engineering technique based on principles of strength of materials and the layered approach. To assess accuracy of the technique, deflections have been calculated for experimental prestressed concrete beams reported in the literature. Comparison has been earned out with the predictions of the well-known design code methods of different countries.

SHORT-TERM DEFORMATIONAL ANALYSIS OF PRESTRESSED CONCRETE BEAMS USING FLEXURAL CONSTITUTIVE MODEL

Abstract In this paper, an attempt has been made to extend application of the recently proposed Flexural constitutive model to short-term deformational analysis of flexural prestressed concrete members. The relationship of tensile concrete is based on smeared crack approach and accumulates cracking and the tension stiffening effects. The Flexural constitutive model was applied in a simple engineering technique based on principles of strength of materials and the layered approach. To assess accuracy of the technique, deflections have been calculated for experimental prestressed concrete beams reported in the literature. Comparison has been earned out with the predictions of the well-known design code methods of different countries.

INTEGRAL CONSTITUTIVE MODEL FOR DEFORMATIONAL ANALYSIS OF FLEXURAL REINFORCED CONCRETE MEMBERS/INTEGRALINIS FIZINIS MODELIS LENKIAMŲJŲ GELŽBETONINIŲ ELEMENTŲ DEFORMACIJOMS SKAIČIUOTI

A new integral constitutive model has been developed for short-term deformational analysis of flexural reinforced concrete members. The integral constitutive model consists of traditional constitutive relationships for reinforcement and compressive concrete and the integral constitutive relationship for cracked tensile concrete which accumulates cracking, tension stiffening, reinforcement slippage and shrinkage effects. A new method has been developed for determining average stress-strain relations for cracked tensile concrete from flexural tests of reinforced concrete members. For given experimental moment-curvature or moment-average strain curves, the material stress-strain relations (including the descending branch) are computed from the equilibrium equations for incrementally increasing moment assuming portions of the relations obtained from the previous increments. Using the method proposed, a number of average stress-strain relations for concrete in tension has been derived from beam tests reported by different authors. Analysis of the relations has shown that their shape mostly depend on the reinforcement ratio as well as diameter and surface of reinforcement bars. The length of the descending branch of the relations reflecting the tension stiffening effect was far more pronounced for lightly reinforced beams with deformed bars of small diameters. For the first time, a quantitative dependence (1) has been established for flexural members between the length of the descending branch and the reinforcement ratio. On a basis of the derived relations, a new stress-strain relationship, called the integral constitutive relationship (2) for cracked tensile concrete in flexure, has been proposed. Accuracy of the proposed integral constitutive model has been investigated by calculating deflections for a large number of experimental reinforced concrete beams (reported by several investigators) for a wide range of values of parameters such as the specimen dimensions, concrete strength, reinforcement ratio, reinforcement bar diameter and surface characteristics. Comparison has been carried out with the predictions made for well-known constitutive relationships of tensile concrete and design code methods. For beams with average and high reinforcement ratios (p > 0.7%), accurate predictions have been made by all the methods yielding standard deviations for relative deflections from 8.8 to 10.3%. However, predictions for lightly reinforced beams (p ≤ 0.7%) were far less accurate. These inaccuracies are related to the increased influence of the tensile concrete which characterised by is a highly dispersed value. For lightly reinforced beams, the most accurate predictions in terms of standard deviation (14.0%) have been achieved using the proposed integral constitutive model. Relatively accurate predictions were also made by the SNiP (former Soviet code) and the ACI methods yielding standard deviations of 20.1 and 22.0% respectively. The EC2 (Eurocode) method underestimates the cracking moment and often overestimates significantly the corresponding deflection, in some cases yielding an error of over 100%. Surprisingly, predictions made by the design code methods were superior than those based on the use of well-known constitutive relationships for cracked tensile concrete. An efficient combination of accuracy and simplicity has been achieved for the integral constitutive model. This allowed to incorporate the model into a simple engineering technique for deformational analysis of flexural reinforced concrete members based on classical principles of strength of materials extended to layered approach and use of full material diagrams. In the given form, the integral constitutive model can be readily used not only in the simple engineering technique, but also in the finite element analysis. These main directions are envisaged in further development of the integral constitutive model for deformational analysis of reinforced concrete structures: a) based on new experimental data, further quantitative investigation of the influence of such parameters as strength of tensile concrete, reinforcement ratio, diameter and surface of bars, section height, shape of the cross-section, etc on tension stiffening and possible inclusion of these parameters into both functional and neural network constitutive models; b) assessment of long-term deformations due to creep and shrinkage; c) application of the model for cases of a combined action of a bending moment and axial and shear forces.

Single-multiple Scattering Technique to Simulate a Time-dependent Signal of a Pulse Laser Radar with Separately Located Illuminating and Receiving Platforms

A technique for calculating the time-dependent signal of a laser radar with a narrow angle of the field of view and separately located receiver and laser is proposed. The laser is assumed to have a short pulse and the results are valid for relatively uniform meteorological situations. This technique is based on the use of a single-multiple scattering model of the aerosol space and 'weighted' influence energetic coefficients of elementary volumes of aerosol space, taking account of spatial, energetic, temporary and other parameters of a radiation source and receiver. Taking into consideration a number of approximations, a relatively simple engineering technique to estimate a laser radar signal is described.