In recent years, nano technology has been significantly implemented in geotechnical engineering, especially for soil remediation. Using this technology has improved soil resistance parameters and led to the stabilization of many problematic soils. Clay soils, due to their nature, have a large dispersion on the surface of the earth. The widespread dispersion of these types of soils in the site of structures, describes the necessity of studying and investigating new methods of improving and amending the resistive properties of these soils. This research is a review of the use of nanotechnology for the improvement of soil resistive properties by geotechnical researchers.
Advanced jet training still relies on old concepts and solutions that are no longer efficient when considering the current and forthcoming changes in air combat. The cost of those old solutions to develop and maintain combat pilot skills are important, adding even more constraints to the training limitations. The requirement of having a trainer aircraft able to perform also light combat aircraft operational mission is adding unnecessary complexity and cost without any real operational advantages to air combat mission training.
Thanks to emerging technologies, the JANUS project will study the feasibility of a brand-new concept of agile manoeuvrable training aircraft and an integrated training system, able to provide a live, virtual and constructive environment. The JANUS concept is based on a lightweight, low-cost, high energy aircraft associated to a ground based Integrated Training System providing simulated and emulated signals, simulated and real opponents, combined with real-time feedback on pilot’s physiological characteristics: traditionally embedded sensors are replaced with emulated signals, simulated opponents are proposed to the pilot, enabling out of sight engagement. JANUS is also providing new cost effective and more realistic solutions for “Red air aircraft” missions, organised in so-called “Aggressor Squadrons”.
Windows and shading devices play a significant role in designing building facades to control the rate of the received daylight and improve visual comfort. This study is aimed to provide an optimization basis for building’s façade considering two variables of Annual Sun Exposure (ASE (1000/250h)) and the view to outside of an office. In this research, the effect of various parameters of shading louvers to the south was investigated in Tehran, Iran. The parameters were number, depth, angle as well as thickness. In this review, Rhino/Grasshopper plug was employed for simulations; moreover, Galapagos evolutionary solver component was used to run the optimization process. This study’s findings showed that it was possible to reach a view of nearly 90% of the interior spaces while the value of ASE (1000/250h) still remained in the reasonable range.
Rutting occurs due to accumulation of incrementally small permanent deformations from each load application and it can cause irreparable problems in pavements. On the other hand, the Marshall Mix design which is known as the main method in Iran, the lack of a simple test to determine specimen resistance to permanent deformation as the major reason for asphalt rutting is noticeable. Although today many devices are used for rutting measurement, none of them have the ability to use in wider field. In addition, prevalent methods of evaluating rutting potential are usually costly and time consuming. Mentioned parameters illustrate the necessity of developing a simple method, not only having fine precision, but also are able to predict rutting performance with low cost in the short term in laboratory. In this research, after performing the main tests on specimens, IDT test results and Marshall Parameters were used to develop a mathematical model to estimate specimen rut depth. The model is validated by using ANN and makes it possible to evaluate mixtures rutting potential while OBC is being determined in laboratory. So not only is there no need to use expensive instruments of rutting test, but also a remarkable time saving in mix design procedure is achievable.
This work aims to study the possibility recycling of foundry sand wastes (FSW) as a cementations additive and fine aggregate in self-compacting mortars (SCM). For this, an experimental study was carried out to evaluate physical and mechanical properties of SCM. Firstly, sand is substituted by the foundry sand waste at dosages (0%, 10%, 30%, and 50%) by weight of the sand. Secondly cement is partially substituted by crushed foundry sand waste at different ratio (0%, 10%, 20%, 30%, and 50%) by weight of cement. The obtained results show that up to 50%, (FSW) can be used as fine aggregate for mortars without affecting the essential proprieties of mortar. However, beyond 50% of sand substitution, mortars lose their fluidity. The compressive strength of the mortars with 50% of cement substitution decreased compared to the control mortar. Value of the highest compressive strength recorded at 28 days, is of the order of 50 MPa for the mortar with 20% of cement substitution. Also, stress-strain curve show an acceptable mechanical behavior of FSW-based mortar at 50% of sand substitution.
The paper topic is related to the use of Geographic Information System and remote sensing in analysing the spatio-temporal dynamics of a post-socialist city. The purpose of this study is to highlight the changes in the land use of the Băneasa neighbourhood, located in the northern part of the capital city of Romania. The changes have been analysed from the nineteenth century to the present. The authors used historical mapping using old maps, as well as digitizing aerial photographs using the Geographic Information System. There has been an accelerated territorial evolution in the last 70 years, marked by the impact of the socialist policy of intensive urbanization, when the urban-type systematization was applied through the construction of collective dwellings, to which were added some important industrial units. After 1990, the dynamics of the tertiary sector generated significant changes in the physiognomy of the urban landscape, observing the increase of the built space (commercial spaces, new residential areas) at the expense of green spaces, tree nurseries, greenhouses and industrial sites. The most recent stage of evolution, however, has brought the most profound changes in the landscape of the Băneasa district, as a result of the new political and socio-economic context, marked by the collapse of communism. Thus, in the last 30 years, the capital city has registered an uncontrolled urban growth dynamic, this being characteristic of other large urban centres at the national level as well favoured by less strict, inconsistent and incomplete urban legislation.
This article has a theoretical and experimental character. It presents the characteristics of two main thermoplastics used in the aerospace industry – poly ether ether ketone (PEEK) and poly phenylene sulphide (PPS). The selected materials are compounds for the production of thermoplastic polymer matrix composites. The paper presents a literature review of the application of thermoplastic polymer matrix composite materials in aviation. Additionally, the paper focuses on the characteristics of carbon fibre-reinforced polymer (CFRP) which plays an important role in the production of aerospace components. Testing methods have been chosen on the basis of the type of composite matrix. The article contains the most important mechanical properties and general characteristics of thermoplastics used as a matrix for CFRP type composites used in the aerospace industry. Individual test procedures which allow for the evaluation of mechanical properties of composite materials on a thermoplastic polymer matrix, have been described. Mechanical tests such as static tensile test and bending of short beams were carried out in order to examine CFRP composites.
The article addresses the recent problem of borehole lifting of oil containing sand solids. The presence of sand in oil produced results in a reduced operating life of downhole equipment. The problem of preventing sanding up and sand formation in pumping equipment may be solved and stable sand production may be ensured by producing oil using borehole screw pumps with a surface-type drive, in which the screw is rotated by rotating hollow rods. Rotating hollow rods improve carry-over of sand particles to the surface with rotational oil flow by imparting additional momentum to these particles. Rotational variables of the pipe (cylinder) that enables transport of solids are set only for the air flow moving in a horizontal pipe (cylinder). The purpose of the study is to establish pipe rotational variables in directional wells that enable stable sand transport with fluid flow. Work results have been obtained from numerical studies using the differential equation system and rules of theoretical solid movement, computer simulation and experimental results processing at a laboratory facility. Theoretical study results have been acknowledged by experimental studies. The work establishes the criteria that allow defining the speed range of directional hollow rods that enables carry-over of solids to the surface with fluid flow. Study results may be used to produce oil with submersible screw pumps with a surface-type drive that use hollow sucker rods for pump down.
The paper presents the validation procedure of the model used in the analysis of the composite blade for the rotor of the ILX-27 rotorcraft, designed and manufactured in the Institute of Aviation, by means of numerical analyses and tests of composite elements. Numerical analysis using finite element method and experimental studies of three research objects made of basic materials comprising the blade structure – carbon-epoxy laminate, glass-epoxy composite made of roving and foam filler – were carried out. The elements were in the form of four-point bent beams, and for comparison of the results the deflection arrow values in the middle of the beam and axial deformations on the upper and lower surfaces were selected. The procedure allowed to adjust the discrete model to real objects and to verify and correct the material data used in the strength analysis of the designed blade.
According to the applicable regulations, in the case of a decision on the location of an investment consisting in the construction and commissioning of a helicopter landing field, it is necessary to carry out an environmental impact assessment. At the same time, due to the emission of noise related to the expected change of acoustic climate parameters, the indicators required under the applicable law related to building acoustics and also impact of vibration on the structure of buildings should be taken into account. The article discusses particular groups of issues related to the assessment of the impact of helicopter landing field on the environment and the hospital building. On the basis of the presented results of analyzes, a postulate concerning the necessity of introducing a comprehensive assessment methodology, including specific groups of issues, was formulated.