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Grinding aids to increase grinding efficiency in cement production are materials that can produce large amounts of high-quality cement in a short time by reducing surface energy by preventing particle agglomeration and improving fluidity. In the paper, a grinding aid using glycerol-waste antifreeze(GAP) is prepared and its effect on the grinding properties of clinker is investigated in contrast to that without the grinding aid. The results are as follows: The angle of repose of the cement powder added with GAP decreases as the grinding time increases (decreases by 3.8° when the grinding time is 60 minutes), indicating that it increases the flowability of the powder. On the contrary, the residual amount of 45µm sieve is also significantly reduced (4.6% decrease) and the specific surface area increases (30.5m2/kg), which results in an increase in the grinding efficiency. In the size range of 3 to 32µm, it increases the particle content, makes the particle size distribution uniform, the 7d and 28d activity index of the powder is improved by 5% and 6%, respectively, and increases the compressive strength of the cement. In addition, it is confirmed that the performance of the TEA grinding aid and the grinding aid are similar, and are very effective in terms of economy.

The Optical Fiber-based communication system has established its proficiency and inevitability towards regular progress and advancement worldwide. The most attractive wavelength for optical fiber communication is 1.55 μm, as it represents the lowest loss. The other challenging parameter ‘Material Dispersion’ gets reduced to ‘Zero’ at 1.27 μm wavelengths for conventional pure silica-based Optical Fiber. To improve the system towards a better unification between the loss and dispersion, the Dispersion Shifted Fiber (DSF) has been introduced. The Dispersion Flattened Fiber has introduced the concept of flat dispersion over a wide range of wavelengths. But the effective combination of the mechanisms to compensate for all the challenges is yet to be established properly. The said mechanisms are complex to design and implement. So, there is an immense scope to search for an alternative to get control over the loss and dispersion. At present, a fair number of material compositions of optical fiber are reported with different specifications. Our study on some of these fiber compositions has produced some interesting data towards the broader flatness and the minimum dispersion effect over a considerable range of wavelengths around the Zero Material Dispersion Wavelength (ZMDW). It helps to have more effective wavelength division Multiplexing (WDM). In this paper, we have studied different prospective options of optical fiber doping profiles to explore and propose an effective and optimized alternative among the available fiber profiles. We have studied the samples of pure SiO2 fibers along with B2O3 and GeO2 doped fibers and samples of Fluoride-based ABCY and ZBLAN glass Fibers to propose an effective combination of materials among the available options to get the optimized conjugation of loss and dispersion. Our report on the comparative study of different fiber materials has produced some effective results to have minimum material dispersion at the lowest loss wavelength to invite worldwide attention from system designers.

Focusing 3-axis diffractometer set-up equipped with bent perfect crystal (BPC) monochromator and analyzer offers the sensitivity in determination of strains Dd/d < 10-4 in polycrystalline materials which is about one order of magnitude higher with respect to that of conventional 2-axis neutron scanners. It also offers possibility of line profile analysis for reasonable sample volumes and counting times. In this paper, the feasibility of using the 3-axis set-up even for measurements of rather large bulk polycrystalline samples with an acceptable resolution is presented. As the 3-axis set-up exploits focusing in real and momentum space, by a proper adjustment of the curvature of the analyzer, a high-resolution determination of the lattice changes can also be achieved even on large irradiated gauge volumes, though with a slightly relaxed resolution. It can be successfully exploited namely, in the strain/stress measurements on samples exposed to an external load, e.g. in tension/compression rig, in aging machine etc. In addition to the original performance where the analysis is carried out by rocking the BPC analyzer and the neutron signal registered by a point detector, a new alternative is offered which uses a fixed rocking angle position of the analyzer and the detector signal is registered by a one-dimensional position sensitive detector (PSD). This trick makes possible in some cases the elastic strain/stress measurements considerably faster and thus reduces the drawback of the time consuming step-by-step analysis.

Concrete members are reinforced by steel fibers to overcome their brittle nature. This paper is focused on the effect of percentage of fiber and the maximum aggregate size on mechanical properties of concrete samples such as compressive and tensile strengths, and ductility. The mean values of these quantities show that by increasing the reinforcement content to 0.66% and the size to 12.5 mm, there is a dramatic improvement on properties of samples. Also, they demonstrate that the size of coarse aggregate has more effect on improvement of the quantities in comparison to steel fiber content and changing the size and fiber content has more effects on ductility than mechanical properties. Statistical approach which considers standard deviations of experimental data, confirms that the gravel regardless of fiber content, leads to the highest improvement on properties with size of 12.5 mm. But the results show for volumetric steel fiber without considering aggregate size, is 0.33%. This clearly indicates the effect of data scattering on mean values of mechanical properties and ductility.

Carbon Fiber Reinforced Polymer (CFRP) is an anisotropic material with outstanding tensile strength in the direction of axial but low compressive strength in the direction of radial, so the radial compressive failure and sliding failure are easy to occur in the practical application of compression and hanging wires. In this paper, the influence of different parameters on radial compressive failure and sliding failure is studied. The finite element method is used to simulate and analyze the CFRP and wedge clamp to find optimum condition parameters to make the CFRP neither sliding failure nor radial compressive failure. The parameters are as follows: interference between the CFRP and the inner wedge, friction coefficient between the CFRP and the inner wedge, angle of the wedge, inner wedge material elastic modulus. The results show that the most appropriate parameter is: the interference between 0.0236mm and 0.0252mm, the friction coefficient between 0.194 and 0.206, the wedge angle is greater than 1.75° and the elastic modulus of wedge material has little influence on the compressive failure and slippage failure of the CFRP.

In this paper, the post ballistic impact behaviour of kevlar-glass fibre hybrid composite laminates was investigated against 9×19 mm projectile. Eight different types of composite laminates with different ratios of kevlar woven fibre to glass fibre were fabricated using hand lay-up with epoxy matrix. Ballistic behaviour like ballistic Limit (V50), energy absorption, specific energy absorption and Back Face Signature (BFS) were studied after bullet impact. The results indicated that as the Percentage of glass fibre is increased there was a linear increment in the ballistic behaviour. Addition of 16% kevlar fabric, composite sample meets the performance requirement of NIJ0101.06 Level III-A. Since the maximum specific energy absorption was observed in Pure Kevlar samples and the adding of glass fibre increases the weight and Areal Density of the sample, further investigations need to be carried out to utilize the potential of glass fibre for ballistic applications.

The important characteristic in the creation of longitudinal splitting cracks in pretensioned concrete members has found to be the geometry of the pre-stressing wire indents. Longitudinal splitting along prestressing tendons can result in severe splitting of prestressed member in the field under loading over time. The research evaluated the influence of wire type indentation on the longitudinal splitting in prestressed concrete members fabricated with different concrete mixtures and different compressive strength of concrete. A key objective was to find the best type of wire to avoid failures in the field. A study was conducted at Kansas State University to understand the effect of wire type on the longitudinal splitting between prestressing steel and prestressed concrete. Three different types of wires will be presented in this paper denoted as “WB”, “WF” and “WQ”. The wires have different parameters which include indent depth, indent width, indent sidewall angle, indent pitch and indent volume.

The paper presents a series of experimental researches performed using the design of experiments method RSD (Response Surface Design) for modeling and optimizing the welding process of PE 100 pipelines, used in natural gas distribution. In this sense, the aim was to analyze the influence of controllable factors such as pressure, temperature and time on the objective functions, aiming to obtain certain characteristics of the welded joint. By modeling the welding process, based on the results obtained, an optimal welding procedure was established and validated to meet the conditions imposed on the objective functions.

This paper summarized the research work carried out by a team from Department of Steel Structures and Structural Mechanics, together with Department of Materials Science and Engineering, from University Politehnica Timisoara, which tried to determine the possibility to use welding for obtaining built-up cold-formed steel beams made of corrugated galvanized steel sheets (grade S350GD+Z). There were analyzed two joining processes: MIG brazing and Resistance Spot Welding with the aim to replace the self-drilling screws used until now. The results are very promising and these solutions of joining have beside economic advantages also technical and quality ones.

The paper aims to report preliminary researches towards to development of new hybrid welding system by coupling a microwave beam with a TIG torch. The main research was focused on the designing of hybrid system as well as to establish the heating/welding mechanism by coupling two different thermal sources. Therefore, a specific welding chamber was designed taking into consideration the limitations provided by microwave waveguide technical specs, geometrical shape and dimensions of the TIG torch as well as the temperature monitoring during welding process and video surveillance for data recording. A microwave generator with adjustable power from 0 to 1250 W was coupled with a TIG torch and welding power source in order to establish the main parameters for hybrid system. The preliminary researches reported that the MW-TIG hybrid welding could be applied to eutectic joining of materials using low power (up to 600 W) injected from microwave generator as well as low welding current (up to 20 A). The flow of shielding gas have been established initially to 2 l/m. The research related to stabilization of MW-WIG plasma arc have been studied by increasing the flow of shielding gas up to 10 l/m. The results have shown that the microwave generator and TIG torch can be coupled to obtain hybrid-welding process without any matching tuning devices but with risks for damaging the microwave generator. Further researches will be done in order to design auxiliary devices to optimize the hybrid-welding process and to avoid any unwanted plasma arc discharge from welded base materials to microwave generator. In terms of temperature monitoring, an infrared pyrometer has been used. The IR pyrometer was targeted to the base materials in order to be able to measure their temperature without any influences from plasma arc. The results obtained have shown a stable plasma at average microwave power around 400 W even without any TIG current.

The paper presents the results of researches carried out by a joint team from Department of Steel Structures and Structural Mechanics, together with Department of Materials Science and Engineering, from University Politehnica Timisoara, focused on the possibility of creating built-up cold-formed steel beams made of corrugated galvanized steel sheets by resistance welding, which will replace the similar beams built by self-drilling screws. Resistance spot welding technologies were developed and tested, together with mechanical testing of the welded joints, which were performed in our laboratories. The results obtained and presented confirm the good quality of the welded joints and, as a result, the good capability of this technology to be used in production, to replace the old type of beams.

The paper aims to report researches in microbonding process of composite magnetic materials using as thermal source the heat produced in base materials by the conversion of the electromagnetic waves with high frequency into thermal energy. This technology can be applied by targeting the base materials with microwaves and taking into account that composite magnetic materials based on ferrites, present good absorbance and conversion properties of the microwaves into heat. For experimental research, the base materials were sintered sampled of raw products obtained from stoichiometric mixtures of 6Fe2O3 + BaCO3. The raw products were obtained by milling and alloying processes using planetary ball mills. The milling and alloying processes have been perfomed in dry environement for homogeneous mixtures and wet environment for mixtures obtained using mechanical alloying. In terms of eutectic alloys used for microbonding, there have been used lead free Sn96,5%+Ag3%+Cu0,5% with melting point around 2170 C. The microbonding process have been perfomed in two steps: first step was focused on prepairing the base materials by cleaning and deposition of eutectic alloys on their surfaces; the second step was the heating of the base materials in microwave field. A microwave generator with adjustable input power from 0 W to 6000 W with a WR340 waveguide have been used as thermal sources. The researches have shown that the base materials were bonded using less than 10 % of microwave power and the eutectic alloys reached the melting temperature în less than 3 seconds when the magnetron was set to full power. A matching load impedance automatic tuner up to 6000 W have been used for increasing the level of absorbed power from nicrowave generator to samples and decreasing the level of rejected power from composite magnetic material to microwave generator. The temperature have been measured using IR pyrometers with range measurement between 0 and 7000 C. The process can be succesfully applied to a large scale for small parts of electrical engines with permanent cermic magnets.

Developing a non-destructive method which delivers fast, accurate and non-invasive results regarding the concrete compressive strength, is an important issue, currently investigated by many researchers all over the world. Different methodologies, like using the simple non-destructive testing (NDT) or the fusion of different techniques approach, were taken into consideration in order to find the optimal, most suitable method. The purpose of this paper is to present a new approach in this direction. The methodology consists in predicting the concrete compressive strength through ultrasonic testing, for non-destructive determination of the dynamic and static moduli of elasticity. One important, basic assumption of the proposed methodology considers values provided by technical literature for concrete dynamic Poisson’s coefficient. The air-dry density was experimentally determined on concrete cores. The dynamic modulus of elasticity was also experimentally determined by using the ultrasonic pulse velocity (UPV) method on concrete cores. Further on, the static modulus of elasticity and the concrete compressive strength can be mathematically calculated, by using the previously mentioned parameters. The experimental procedures were performed on concrete specimens, namely concrete cores extracted from the raft foundation of a multistorey building; initially they were subjected to the specific NDT, namely ultrasonic testing, and the validation of the results and the proposed methodology derives from the destructive testing of the specimens. The destructive testing is generally recognized as the most trustable method. The precision of the proposed method, established with respect to the destructive testing, revealed a high level of confidence, exceeding 90% (as mean value). It was noticed that even the cores with compressive strength outside of mean range interval (minimum and maximum values) presented high rate of precision, not influencing the overall result. The high rate of accuracy makes this method a suitable research background for further investigations, in order to establish a reliable NDT methodology which could substitute the very invasive and less convenient, destructive method.