This research was focused on evaluating the influence of the different variables that affectsplitting in prestressed concrete members, particularly prestressed concrete ties. These include the thickness of concrete cover, release strength of concrete, and the type of wire indentation. Different combinations of these variables can affect splitting. This research was focused on finding the best possible material characteristics to avoid potential failures in the field. The objective of this research was to set the minimum value of the thickness of concrete cover, for different wire types used in manufacturing having given types of aggregate for concrete mixture. The importance of this research was to identify the best materials and the best system (concrete, wire, cover) designs before the production of prestressed concrete ties. Splitting test results presented in this research were focusedon three different thicknesses of concrete cover, three different concrete mixes, a 4500psi concrete release strength, and seven different indented wire types.

In this study both natural ageing (NA) and artificial ageing (AA) behaviour of Al-Mg-Si aluminium alloy having trace addition of 0.04 wt.% Sn (Tin) was studied at different solution heat treatment (SHT) temperature and time, ageing time and temperatures. Microstructural analysis was performed to identify the intermetallic phases. It was observed that peak NA hardness strongly depends on the SHT temperature and time. SHT at 530 for 0.5 hour, slows down the peak NA hardness attaining time of the alloy to a maximum of 5 days. But as the SHT time increases to 3.5 hours, the peak NA hardness attaining time reduced to 1 day. Alloy SHT at 530 for 1 hour attain a maximum peak hardness of HRB 24 during 3 days of NA. Artificial ageing improved the hardness of the NA alloy to a maximum of HRB 41 during 12 hours of ageing at 190 . The overall hardness of Al-Mg-Si-Sn as-cast alloy increases by 32 % during ageing process.

Ultrasonic inspection is a well-known method in non-destructive testing. Based on the changes in the ultrasonic sound speed, tested materials are evaluated in terms of internal defects. In addition to flaw detection, ultrasonic testing is used in the material characterization of ductile cast iron. Graphite shape detection has been widely investigated by ultrasonic inspection in literature. However, most of the measurements has been conducted at single frequencies. In this work, three different nodulizer included casting operations were carried out to produce ductile cast irons having various graphite morphologies. A wide frequency range of 1.25-10 MHz was selected in the ultrasonic inspection. In addition to graphite morphology analyses, the relationship between ultrasonic sound speed and mechanical properties was studied. In the mechanical analyses, hardness and tensile testing properties were investigated for the specimens. From the results, ultrasonic sound speed exhibits a considerable dependency to the graphite morphology. In addition to a good graphite detection capability, ultrasonic inspection exhibits promising results for predicting the mechanical properties such as hardness, elastic modulus, yield strength and tensile strength. It is also found that there is a slight increase in the ultrasonic sound speed by increasing the frequency, although sound speed is independent from this parameter.

This investigation was carried out to identify the engineering properties of compressed interlock earth blocks manufactured from locally available lateritic soil and introduce to use the manufactured soil blocks to minimize the material and finishing cost for the low cost housing projects. The soil samples used in this study were well-graded lateritic sandy soil which has the composition of 1.9% gravel, 94% sand and 4.1% silt / clay. These soil samples were passed through the 100-mesh sieve and mixed with ordinary Portland cement to prepare the admixture. While compressing through a hydraulics jack by varying the compositions and the volume of soil-cement admixtures, compaction soil blocks were manufactured in a locally fabricated 250 mm x125 mm x100 mm standard steel mould. The manufactured soil blocks allowed to cure while spraying small quantity of water and covering with polythene for 28 days. Average compressive strengths of soil blocks made with 5% cement with 1.6:1 and 1.8:1 volume compactions were 1.3 Mpa and 1.9 Mpa, respectively. However, both compressive strength values were less than the standard limits of 2.8 MPa stated in SLS 1382:2009, local standards for soil blocks used for construction industry. However, soil blocks made with 10% cement under same compaction ratios attained compressive strengths of 3.0 MPa and 3.6 MPa respectively and it is above the required standards limits. However, 15% and 20% cement containing earth blocks have much higher compressive strengths but increase the cost of production. Regression analysis results confirmed the strong correlation between cement content and the compressive strength of the soil bricks. The soil bricks manufactured with more than 12.06% cement soil mix by maintaining compaction ratio into 1.6:1 or Soil bricks manufactured with more than 5.16% cement mix by maintaining compaction ratio into 1.8:1 will produce standards soil bricks for construction industry and these results further confirmed that wet and dry compressive strength of soil bricks will increase with increasing the compaction ratio and the cement content. However, when considering the compressive strength, water absorption level and cost effectiveness, soil bricks manufactured by maintaining compaction ratio into 1.8:1 with more than 5.16% cement mix will produce required standards cost effective soil bricks for construction industry.

Malaria caused by Plasmodium falciparum continues to be a major public health problem especially in tropical and sub-tropical regions of the world. Considering the growing resistance of parasites to anti-malarial drugs and of vector mosquitoes to insecticides, there is no doubt that the effective vaccine is the most awaiting tool to reduce the risk of malaria. Our synthetic studies have shown that a loop region (AD22 = 256ASEFYNSENKTYDLDFKTPNND277) of Plsmodium falciparum enolase has antigenic reactivity against patients’ sera and AD22 can produce inhibitory antibodies against in vitro parasite growth. In this paper, we will briefly present our ongoing research of malaria vaccine development and related model studies.

β-AgI thin films with thicknesses of 0.09–8.9 µm were prepared on polyethylene terephthalate (PET) substrate. Dependence of ionic conductivity on the thickness of the β-AgI thin film was measured via impedance spectroscopy in the temperature range of 300–330 K. It has been confirmed that the ionic conductivity of the b-AgI thin film is several hundred times higher than the b-AgI bulk. The enhancement of ionic conductivity is considered to be due to the formation of a high ion-conducting region near the hetero-interface region of b-AgI and PET. Furthermore, it has been suggested that the activation energy and carrier density may change depending on the distance from the interface, and the thickness dependence of enhancement in ionic conductivity may be related to the film thickness dependence of crystal orientation and structural disorder of β-AgI thin films.

This paper proposes new EMI reduction technologies and automatic output voltage ripple cancellation method for the PWM buck converter with voltage-mode or current-mode and the ripple-controlled converters. Genenrally, modfying the clock frequeny is effective to reduce the EMI noise, but it may increase the output ripple substantially. We have developed techniques to cancel the increased ripple by modifying the slope of the saw-tooth signal or current of the ripple injection circuit. The EMI spectrum of the operating frequency is reduced by more than 15dB and the modified large ripple is canceled to the stable level.

The tensile deformation behaviour of magnesium alloy AE44 (Mg-4Al-4RE) under strain rates ranging from 10-6 to 10-1 s-1 has been investigated. Present study shows that the deformation mode begins with the activation of elastic (Stage 1), followed by <a> basal slip and twinning (Stage 2), <a> prismatic slip (Stage 3) and finally to <c+a> pyramidal slip (Stage 4). The commencement of these deformation mechanisms results in four distinct stages of strain hardening in the stress-strain curve. In this work, the four stages of deformation behaviour are modelled, and an empirical equation is proposed to predict the entire stress-strain curve. Overall, the model predictions are in good agreement with the experimental data. This study on the decomposition of stress-strain curve into four stages provides insights into the contribution of individual deformation mechanism to the overall deformation behaviour and opens a new way to assess mechanical properties of die-cast magnesium alloys.

This work presents some logistics and transportation challenges that were solved by 3 different student groups from 3 different European entities. These groups were: the STC Group, from The Netherlands, made of 12 students; the FHOO Group, from Austria, which comprised a number of 10 students and the IMST Group from Romania, made of 12 students. Each of the group had a specific task of finding the best logistic and transportation solution for each of their task. Also, they need to take into account several important parameters like air pollution problem, the shortest way of reaching to destination, the way of transport and others, which were decisive in choosing the right solution.

In the paper is presented the analysis of tool steel used for making a knife for a mill for grinding plants. The material used for the knife is about 1% carbon and is symbolized by RWL34. To improve the properties of the material, especially the knife cut, a thermal treatment were made and was measured hardness, wear resistance and microscopic analyzes of the metal. The paper presents the values of the mechanical properties on the initial sample, on the hardening sample and on the sample subjected to a hardening and tempering treatment, as well as the graphs related to them. The next step in finalizing the analysis of the grinder mill knife is to study the behavior in operation and the possible corrections that should be made.