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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 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.

Fast development of Sustainability and Circular Economy concepts has been materialized in European Parliament Directive no 2019/904. This Directive requires to reduce the consumption of plastic material for the manufacture of disposable packaging. In spite of the aggressive campaign against plastic materials usage, there are huge advantages which must be considered before replacing them by other alternative materials. Downsizing, Lightweighting and Downgauging technics are employed from early stage in designing new products made by plastic materials. Product recyclability features and recycled materials usage for products manufacturing need also to be assessed during the design and testing phase. This article proposes ultrasonic welding as an alternative technology for manufacturing the hollow polypropylene balls. With the traditional technology, the manufacturing of these balls results in an uneven wall thicknesses and a large technological runner of material that needs to be grinded and reintroduced into the injection equipment and this involves high consumption of raw material and energy. The proposed method of manufacturing these hollow balls consists in forming the ball from two ball halves joined together by ultrasonic welding. This process will result in significant savings in raw material and energy. As a case study, the manufacturing of deo roll balls have been considered. Several experimental researches have been made using ultrasonic welding at frequencies of 20 kHz and 35 kHz. Significant improvements on the capabilities of the ball external diameters have been recorded by ultrasonic welding using the frequency of 35 kHz. Further testing and comparative study of mechanical properties must be considered in order to define the best process parameters for hollow plastic balls manufacturing by Ultrasonic Welding.

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.

The paper proposes the analysis of an alternative technology for manufacturing deodorant roll-on balls of polypropylene. With the current extrusion-blowing technology, the manufacturing of these balls results in an uneven wall thicknesses and a large technological runner of material that needs to be grinded and reintroduced into the injection equipment, which involves additional raw material and energy consumption.The proposed alternate method of manufacturing these balls (as spherical objects) is to form the ball from two ball halves joined together by infrared radiation welding. This process will result in significant savings in raw materials and energy.Further improvements of dimensional capabilities and control of welding parameters are required prior the transfer on high productivity manufacturing lines. Additionally, this technology can be assimilated into other applications where hollow balls of plastic are used.

Ultrasonic welding is a fast and economical solution for plastic parts. This article proposes Ultrasonic Welding as an alternative technology for manufacturing deodorant roll-on plastic balls. With the current technology, the manufacturing of these balls results in an uneven wall thicknesses and a large technological runner of material that needs to be grinded and reintroduced into the injection equipment.The proposed method of manufacturing these deodorant balls is to form the ball from two ball halves joined together by ultrasonic welding. This process will result in significant savings in raw materials and energy.Further improvements of welding parameters and dimensions are required prior the transfer on high productivity manufacturing lines. This technology can be assimilated into other applications where hollow balls of plastic are used.

Within the WELLFORMED research project, ongoing at the CEMSIG Research Center of the Politehnica University of Timisoara, a new technological solution was proposed for built-up beams made of corrugated steel sheets for the web and thin-walled cold-formed steel profiles for the flanges, connected by spot welding. The research project integrates an extensive experimental program on such beams, using full scale specimens, to demonstrate the feasibility of the proposed solutions and to assess their performance, followed by numerical simulations to characterize and optimize the connecting details. The present paper presents the results of a large experimental program, on small specimens subjected to shear, consisting of two or three layers of steel sheet connected by spot welding.

In this work, polyaniline (PANI)/cotton composite was prepared by in-situ oxidative polymerization and applied to remove Cr (VI) in solution. The as-prepared composite shows a high Cr (VI) removal rate (93.81%) at pH=2. Meanwhile, the adsorption kinetics follows the pseudo-second-order rate equation and the adsorption isotherm data fits well to the Langmuir isothermal model.

The weak solubility of chitosan is the main disadvantage as a delivery carrier for drug application. In this study, a novel soluble in water chitosan derivative N-2-hydroxypropyl dimethyl ethyl ammonium chloride chitosan (N-2-HFCC) was successfully synthesized with low toxicity, a high safety level and used to make nanoparticles as a delivery vehicle for live attenuated Newcastle disease vaccine. In addition, Newcastle disease virus (NDV) La Sota encapsulated in the N-2-HFCC/CMC nanoparticles (NDV/La Sota-N-2-HFCC/CMC-NPs) was prepared by a polyelectrolyte complexation method. The preparation technology of NDV/La Sota-N-2-HFCC/CMC-NPs was optimized by single factor and orthogonal test. The results of this study demonstrated that the optimal conditions for the preparation of NDV/La Sota-N-2-HFCC/CMC-NPs is stirring speed and stirring time of 1200 r/min and 40 min, NDV dosage of 2.0 ml, the N-2-HFCC concentration of 1.25 mg/ml and the CMC concentration of 2.0 mg/ml.

A novel hydrogel was successfully synthesized through doping 4A molecular sieve (4A-MS) into poly (acrylic acid-co-acrylamide) and used for the removal of Cu2+, Ni2+, Cd2+and Pb2+in the solution. The composite hydrogel all exhibited high sorption capacity (SC) and high elution percentage (EP) for the four above heavy metal ions. Simultaneously, the water uptake (WU) of the hydrogel was dramatically decreased and the mechanical strength of the absorbent hydrogel was improved with increasing 4A-MS content.

With the improvement of machining technology, diamond cutting tools are used more and more widely due to the excellent performance of diamond. This document briefly introduced the diamond cutting tool materials and the synthetic technologies, as well as the types of diamond cutting tools. Development situation of methods of machining diamond cutting tools and the grinding technology were also expounded. At the end of the dissertation, summery and future trends of diamond cutting tool technologies were outlined.

Preferential adsorption takes place at the step ledge between adjacent crystal faces, which usually serve as active sites for breaking chemical bonds. In this paper, we present a structural model to interpret the habit modification of single crystals in terms of the step geometries relationship between crystal faces. A new series of high index faces parallel to the ledge between adjacent facets can be explicitly determined from the presence of the symmetry operators in the space group. The relative stability of these new faces undergoes a faceting transition, driven by the adsorbate-induced changes of the step configuration. Combined with the chemical bond-geometric approach, our predictions accurately reproduce the tapering evolutions of KDP crystals in the present of metallic ions. The current work provides a new insight on how changes affecting elementary steps on one face are translated into the emergence of a new crystallographic face.

Ferrocene (Fc) is an organometallic compound of sandwich structure. As the anticancer and excellent electrical activities, ferrocene and its derivatives have many applications in electrochemical monitoring [1-3]. Hydrogen peroxide (HP), with strong permeability and oxidation properties, is the product of many peroxidase catalyzed reaction, and it is widely used in medical and cosmetic fields, even for food bleaching by some illegal merchants which may cause healthy problem. In this study, the polyelectrolyte multilayer films containing ferrocene-derived polymer assembling by sol-gel process [4] was introduced to HP determination as a sensor.

Paper presents the finite element modeling for the stress and temperature as a result of the metal deposition technology. In this case, this research method is the only one that offers information because of the working condition that are total unfavourable for stress and strain gauges. By selecting the most appropriate initial condition, the output data are very close to real result. In the paper, the temperature behavior is model because its influence in structural transformation and the stress because it can cause problems in the situation of an incorrect working technology.

Taizishen and A.camphoratewere used respectively as primary medium and fermentation strain to obtain solid-fermentation tea in this paper. A.camphoratewere inoculated into the optimal medium with Taizishen’s powder of 90%, glucose of 3 %, soybean flour of 6 % and gypsum powder for food of 1 %, and cultured at 26 °C. The fermentation procedure was ended on three days after the mycelia of A.camphorategrowing all over the medium. The content of crude polysaccharides, total triterpenoids and amino acids were 12.03 %, 3.67 % and 4.6 % respectively in the solid-fermentation tea. The tea soup possessed good colour, special fruity from A.camphorate, mellow and full of taste.

Hand-foot-mouth disease is an infectious disease caused by a variety of enterovirus. The enterovirus 7l is the main pathogen of Hand-foot-mouth disease. The main symptoms are the rash or herpes of hand, foot, mouth, buttocks and other parts, bringing aseptic meningitis, brainstem encephalitis and acute flaccid paralysis and other serious neurological complications and pulmonary edema, pulmonary hemorrhage. Hand-foot-mouth disease harms seriously children's health. Currently, the overall treatment of severe Hand-foot-mouth disease adopts the symptomatic therapy. Early identification of severe and early intervention are the keys to the treatment of children with Hand-foot-mouth disease.

Paper presents the main pollutants that appear Gas metal arc welding, the main chemical reactions take place in the melting bath where results the pollutants, determining the impact on the working environment by calculating the coefficient of pollution. The optimization of welding process gives a coefficient of minimum pollution and determines the influence of welding parameters of the system on the appearance of major pollutants elements.

Paper presents the main pollutants of the working environment at welding under flux, methodical determination which the main chemical reactions resulting in pollution and pollution coefficient calculation. A number of welding working regime in order to achieve a coefficient of minimal pollution. The experimental results demonstrate that the process of welding under flux is less polluting than manual arc welding and coated electrode but more polluting than the process of welding in protective gas environment. It shows the influence of welding regime parameters for the most important gas pollutants.

A Duplex treatment consisting in gas nitriding followed by PAPAVD deposition of TiAlN has been proposed as a solution for improving the corrosion behaviour of EN 42CrMo4 steel. The corrosion resistance in 3.5% NaCl solution was evaluated by linear polarization. It was found that the Duplex treated samples exhibited better corrosion resistance and that the corrosion rate decreased significantly from 0.069 mm an-1 (untreated samples) to 0.008 mm an -1 (Duplex treated).

Nanohydroxyapatite (HA) with rod-like shape was synthesized by a cationic surfactant-templated method. Batch adsorption experiments were conducted to investigate its copper adsorption property from aqueous solution. The effect of initial copper ion concentration and contact time were studied. Results showed that HA adsorption capacity increased from 25.6 mg/g to 81.4 mg/g with the increase of initial copper ion concentration from 20 mg/L to 200 mg/L. Meanwhile, the removal efficiency decreased from 64.1% to 20.3%. Moreover, it also revealed that the removal efficiency of Cu2+increased with the increasing contact time and the initial adsorption process is rapidly increased within 15 min and the equilibrium was attained after 15 min.

Sodium acetate has been separated and recycled in waste liquid from production by the process of precipitation, filtration, washing, concentration, crystallization, recrystallization and drying. The recycling of sodium acetate can be completely achieved by reuse hot water and liquor produced during concentrated and crystallization process respectively. Product quality of sodium acetate accords with national standard GB/T 693-1996 chemical pure grade. In the paper, the involved method of the waste water treatment has the characteristics of simple process, convenient operation, less investment and high return. Then, energy conservation and emissions reduction can be achieved when the technological process is used. Therefore, the recycling technology is suitable for industrialized production.

Seven novel aryloxy-acetyl ferrocene derivatives were parallel synthesized under microwave irradiation conditions from chloroacetyl ferrocenes and substituted phenols with the aim of obtaining potential antioxidant agents. The target compounds were identified by IR, 1H NMR, MS and elemental analysis, and their antioxidant assays indicated that all the aryloxy-acetyl ferrocenes had certain effect on eliminating 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. Their antioxidation activity significantly improved when rising the temperature until the temperature was 35°C. The structure-activity relationship analysis showed the electron-donating substituted aryloxyl group could strengthen the radical scavenging abilities, while the electron-withdrawing effects would block antioxidant abilities.

In this paper, green ceramic tapes are joined together by adhesive based lamination technique. The effects of adhesive concentration, pressure on the lamination and sintering temperature on the laminate are mainly discussed. The parameters are also optimized. It was shown that the effect of adhesive concentration and pressure on the lamination is obvious and the effect of sintering temperature is not big. 10 layers of cordierite tapes can be laminated under 2MPa with a dwell time of 3min with PVA by adhesive based lamination. The adhesive based lamination can be used to be an alternative of thermo-compressive lamination.

For the mathematical modeling of the bending behavior on a microgripper compliant arm it is necessary to estimate the compliance impact on the system. In case of low bending force values, the linear dependence between force and elastic deformation is presumed. After performing bending experiments on full section and, respectively, compliant arms, there was determined an elastic coefficient allowing the mathematical modeling of the compliant beam as a full section beam and a moment of inertia reduced proportionally to the calculated elastic coefficient. The modeling results are consistent with the results of the experiments performed on the prototype.

Most metallic constructions and equipment which come in contact with petroleum products are made of steel and are exploited at ambient temperature which can range between −50°C and +50°C in different regions of our planet. When metals and alloys are in contact with pure hydrocarbons (CnHm), they do not react with them. However, rust or different types of depositions can be observed in tanks and pipelines containing gasoline, naphtha, and gas oil. The complex phenomenon of contamination is described in this paper in order to demonstrate its importance, as the number of failures of steel components is growing every year. It is important to understand that the corrosion process proceeds at the interface of different phases. Water, H2S, corrosion products, ions, phenols, organic acids, and other organic sulphur-, oxygen- and nitrogen-containing compounds dissolved in petroleum products are the contaminants that are responsible for the further destruction of the steel components.

The branched polyethylene (br-PE) was synthesized by [ArN=C(An)-C(An)=NAr]NiBr2 (An = acenaphthyl, Ar = 2,6-C6H3(iPr)2) in the presence of modified methylaluminoxane (MMAO) and methylaluminoxane (MAO). The effects of experimental conditions in which ethylene pressure, temperature and time were varied on ethylene polymerization were investigated. The structures of the obtained polyethylene were characterized by high-temperature NMR, high-temperature GPC and DSC. It was found that the activities from MMAO were higher than that from MAO about 10 times, which reaches 107(g/mol Ni·h). The branches of polyethylene prepared from MMAO were about 60/1000C, while that from MAO were about 80/1000C. The branched polyethylene with 84 branches / 1000C was used to toughen isotactic polypropylene (i-PP). The results show that the impact strength of blends improves as the content of branched PE increases. When the content of br-PE is 40%, the impact strength of the blend reaches to 50.24 KJ/m2, which is about twenty times that of PP (2.24 KJ/m2).

Kepayang is a plant commonly found in tropical regions especially in Aceh, which has not been optimally used by local people. Based on traditional processes, kepayang seeds are potentially capable of producing oil. The objective of this research is to examined the effects of specific fuel consumption, power generation, and the thermal efficiency on engine performance by using kepayang seeds oil. The problem will be evaluated the effect of variations of biodiesel fuel (B-0, B-10 and B-20) and variation engine rotation on the diesel engine performance. In order to perform this research, the Yanmar TS-50 engine which had rotation of 2400 rpm and maximum power of 2 kW was selected. By examining the result of the research it was concluded that there were not significant effects of varied fuel consumption on the low speed (1000 rpm to 1800 rpm) engine rotation. However for engine speed more than 1800 rpm there were somewhat effects of them on engine performance. It is evident that at the engine rotation of 2000 rpm, the fuel consumption of biodiesel (B-20) and the power generated were lower than compare to biodiesel (B-10 and B-0). On the other hand, the thermal efficiency for biodiesel (B-20) was higher than compared to other biodiesel (B-10 and B-0).

Resistance to progressive collapse under extreme loading is a measure of the structural robustness, and relies primarily on resistance of key elements, continuity between elements and ductility of elements and their connections. In case some hazards occur simultaneously or consecutively in a very short period of time, e.g. fire after explosion or impact, the capacity of the members and connections can be exceeded and this can initiate the progressive collapse of the structure. The paper presents the results of a research program that focused on the ultimate capacity of connection macro-components under large deformation demands and different loading rates. The specimens were extracted from extended end plate bolted beam-to-column connections with different strength and stiffness ratios to the beams.

The optical and electric transport properties of the Al:ZnO(AZO) and (Cu, Al):ZnO (CAZO) films deposited by pulsed laser deposition (PLD) were investigated in this paper. The experiment found the optical band gap (OBG) of AZO films at room temperature increased from 3.378eV of ZnO to 3.446eV of ZnO:Al (2min) sample, but decreased as continue add Al to ZnO:Al (4min), which were attributes to the Burstein-Moss (B-M) effect. For CAZO films, there is obvious change about hall mobility,ν, and resistivity,ρ, after doped Cu. It can be found that theνdecreased from to and theρincreased from to for AZO and CAZO, respectively, which is due to the scattering increasing between donor carriers and grain boundary as Cu2+ions increase, meanwhile, it was also found the decrease of OBG, which are very help to further understand the electric transport properties and the OBG effect of AZO-based films as well as its devices potential application.

To optimize the prescription of tanshinone IIA lipid microspheres by central composite design method, and evaluate the quality. Through evaluating average particle size, stability constant and the encapsulation efficiency of the lipid microsphere to investigate the concentration of the egg yolk lecithin and the poloxamer and the percentage of Soybean oil in the total oil phase which may impact the properties of tanshinone IIA lipid microsphere. Building the mathematic relation between the index and factor by the binomial expression, according to the best mathematical model of the evaluation indicators to describe response surface and then to use response surface method to predict the best prescription which will be analysed. According to the prescription optimization to prepare tanshinone IIA lipid microsphere and evaluate its quality. The results showed that each index of the binomial equation fitting is good, the correlation coefficient of the average particle size, stability constant and the encapsulation efficiency are 0.97, 0.92 and 0.84 respectively. The optimized prescription is as follows: egg yolk lecithin1.38 g, F68 0.19 g, LCT 2 g, MCT 18 g, all the indexes of the optimized prescription are similar to the target values.

Hip resurfacing arthroplasty is an very interesting and controversial orthopedic concept in the last years [1]. In order to avoid the previous problems associated with the classical hip prosthesis type metal-polyethylene [2], different manufacturer propose the metal-metal prosthesis based on the reproducible quality of manufacturing of metallic components using Co-Cr alloys and better component fixation. Problems that have been encountered to be the reason for failing of the prosthesis can be different (dislocation, femoral neck fractures, vascular damage, avascular necrosis, raised metal ion levels), and could be related to three main aspects: factors related to the patients, surgical intervention and prosthesis [3, 4]. But a very important aspect is the biomaterials used, that will be discussed in the present paper in correlation with biomechanics and clinical aspects. Our study maked on a lot of retrieved BHR prosthesis used in one Romanian orthopaedic clinic present a higher rate of failure than the other similar studies made by other authors [5]. Starting from this point, we analyze carefully many components of the failed BHR prosthesis using stereomicroscopy, scanning electron microscopy (SEM) and EDS. Based on our experimental results especially at the interfaces metal-cement-bone, we identify different potential causes of failure but the main conclusion was that the cementation technique and poor quality of the patient bone are the reasons for most of hip resurfacing prosthesis failure. As future recommendations for the orthopaedic surgeons we could mention the carefully analysis of bone quality for each candidate using advanced techniques like DEXA and a correlation between the bone cement used for prosthesis fixation and the cementation technique.

Based on Pham’s model, the non-isothermal ferrite transformation start temperature and time of Fe-C-Mn-Si alloys were deduced. The parameters of expression were predicted combined with experimental results. The relationship between ferrite transformation parameters Q , C and composition of Fe-C-Mn-Si alloys was obtained. Then the ferrite transformation start curve of Fe-C-Mn-Si alloys can be accurately predicted by the computational method, which can be extended to more complex multi-component alloy systems.

Low life service of steel dies used in copper extrusion brought us to inspect several discarded copper hot extrusion dies in order to identify failures and failure mechanisms. The investigations performed are mainly hardness tests and microscopic investigations. The profiles extruded are circular, rectangular and hexagonal. It was observed that die design is not at fault; rather the die material is to blame for low life service of the tool. Discarded extrusion dies after copper hot extrusions were investigated. The failure of the dies was first observed by naked eye and the observations recorded. From the dies the ones with most plastic deformations and obvious signs of failure were selected. An improvement in die design could expand the service life, but our main concern is the material: a balance between toughness and hot strength is critical, yet this balance is hard to achieve. Other thermal processing of the die is still in question and investigations are currently being performed. At least an increase of tool service life could be achieved by thermal processing of the material to a state prior nanometric carbide precipitation between martensitic plates.

In this paper, Be-doped GaAs were grown by molecular beam epitaxy (MBE), by changing Be resource temperature, we obtained different doping concentration GaAs samples. The morphologies and electrics properties of the samples were investigated by AFM and Hall measurement. Especially, in low temperature and temperature dependent PL spectra, the Be acceptor related emission were recognized, with the doping concentration increasing, the Be acceptor related emission enhanced too.

Steel moment frames are common systems in multi-storey buildings. Even the relatively low stiffness of the system limits the applicability, they remain popular in seismic applications due to the good dissipation capacity. Considered deemed-to-comply in seismic applications, welded beam to column connections experienced serious damages and even failures during strong seismic earthquakes. These failures included fractures of the beam flange-to-column flange groove welds, cracks in beam flanges, and cracks through the column section. To reduce the risk of brittle failure of welded connections, beam weakening near the ends became popular. To assure the desired behavior, i.e. the development of plastic deformations in the reduced beam section zones rather than at the face of the column, proper detailing and sizing is necessary. Today design provisions are limited to long beams, where the effect of shear stresses may be neglected. The application of the same rules for short beams might be non-conservative, and therefore qualification testing is necessary. The study presents the qualification testing of reduced beam sections welded connections of short beams. Both monotonic and cyclic tests were performed and numerical models were validated based on the test data.

Vanadium dioxide (VO2) has attracted much interest in material field due to its unique semiconductor-metal phase transition properties. And now, the problem of stability has been highlighted and concerned for the practical application in VO2. In order to establish a relatively complete guide of stability study on VO2which would contribute to deeply and systematically researches, the article made a review of the stability study on VO2 from thermal excitation, photo-excitation and electro-excitation. Moreover, the key aspects for future research on the stability study of VO2was proposed.

The paper presents a study about thermal behavior of heat sink - power thyristor assembly. The models of power thyristor and the model of heat sink were modeled in SolidWorks. These models have been used in simulations. We take into consideration different conductor materials for heat sinks and different thermally conductive pastes. A thermal analysis has been performed for different places of power module on heat sink. In our study, we have taken into consideration the influence of the different materials of heat sink in heat dissipations. The results of performed simulations realized with Solid Works are presented in the paper.

Total hip prosthese are widely used in total hip arthroplasty, offering many benefit to patients with different articular diseases like osteoarthritis or after different accidents. Many total hip prosthesis are now available to the orthopaedic surgeons to replace the hip articulation, with different design and with components made by different type of biomaterials: metallic (cobalt-chrome and titanium alloys, zirconium-niobium alloy named oxinium), ceramic (alumina, zirconia), polymers (ultra high weight molecular polyethylene-UHMWPE). Even total hip arthroplasty has a high success rate, implant loosening may occur, with different symptoms that could be attributed to metal allergy. Because the stem components of the total hip prosthesis are made by metallic biomaterials, many papers describe the adverse effects related to the release of metal ions (like cytotoxicity, carcinogenicity and metal allergy). There are different types of metal corrosion: intergranular, pitting, crevice, fatigue, stress, fretting, and galvanic. On the other hand, in many cases (like metal-on-metal prosthesis) appear corrosion and wear between two metallic components. This processes are favourable for the aparition of hypersensitivity-related tissue reactions. Especially some metallic ions (nickel, cobalt, and chromium) presents in stainless steels and cobalt-chromium alloys are most known to be released from prostheses components and give metal allergy. Of course, during the time was developped some solutions in order to improve the performance of the hip prostheses components made by metallic components like coating with thin layers using different biomaterials like porous titanium or hydroxiapatite. The aims of this review article were to explore mainly the relationship between corrosion products and implant-related hypersensitivity, the importance of surface treatment for metallic components, try define the effect of metal ion concentrations, and differentiate between allergy and infection in total hip replacement. The long-term performance of the coated components will be also analyzed and synthetic described based on clinical results. Also, some relevant aspects from our clinical experience and retrieved prosthesis analysis using stereomicroscopy and scanning electron microscopy will be shown in order to support the conclusions.

Corrugated web girders emerged in the past two decades. Their main advantages consists in the possibility to use slender webs avoiding the risk of premature local buckling. Consequently, higher moment capacity might be obtained increasing the beam depth with really thin webs, which are stiffened by the corrugations. Increased interest for this solution was observed for the main frames of single-storey steel buildings and steel bridges. A new solution was proposed at the Politehnica University of Timisoara, in which the beam is composed by a web of trapezoidal steel sheet and flanges of back-to-back lipped channel steel sections. This solution uses self-drilling screws for connecting flanges to the web and to ensure the continuity of the web as seam fasteners. Starting from this new technological solution the paper extends and investigates the use of spot welding as seam fastening to build the web, in order to increase the degree of automation of fabrication. Experimental work of specimens in shear having two or three layers of steel sheets connected by spot welding will be presented. The results will be implemented on a numerical model in order to study the behaviour of the beams presented above.