Enginering of Materials

Method of weighted residual has been one of the foremost approximation solution to partial differential equation problems. In this paper a time dependent and boundary-valued strain model obtained from a PPC/CaCO 3 composite experimental data was analyzed using the method of weighted residual. The Galerkin's approach of this approximate method was applied to the model at a constant stress of 17.33 MPa. The discretization of the composite material was therefore, designed to take the form of a linear and one dimensional problem setting.

The article presents the preliminary tests results of three high-strength steels, which are used in structural elements of semi-trailer's construction. Paper presents an analysis of tensile and fatigue test results of high-strength steels like Hardox 400, Hardox 450 and Strenx 700MC. The fatigue tests are in the range from 10 4 to 10 7 number of cycles of applied load with a frequency of 40 Hz. The Wöhler curve shows the results of the fatigue properties of these steels, which are used in the construction of vehicles. Fatigue fractures were subjected to fractographic analysis in order to determine the mechanism of fatigue crack propagation. Fractographic analysis confirmed no effect of inclusions on the test results.

Self-cleaning properties have received significant attention for the importance of their potential. Coatings at Nano-scales offer possibilities of using materials for self-cleaning surfaces. Recent efforts have begun to focus on the kinds of materials including metals, semiconductors and polymers. Such materials can have enormous potential in only a few applications. Moreover, the production of these materials requires high costs with low photo activity. In this regard, TiO 2 and its derived materials have shown acceptable and effective suggestions for this application. Moreover, the mechanism of self-cleaning has been explained by the effect of hydrophilic and hydrophobic. Hydrophilic and hydrophobic can have many applications in different areas like water purification, microfluidics and photovoltaic. In this review, the application of self-cleaning in solar cells and environment as well as TiO 2 derived materials and their applications in water management have been briefly illustrated. In addition, it has been explained that a huge number of self-cleaning materials, applications and improvement in utilities have been essential. In short, we have conducted a comprehensive review of the new approach and to mention numerous materials with hydrophobic and hydrophilic properties would be promising for most environmental concerns. Bio-inspired surface respond in nature through hydrophobic (Cicada Wing, Butterfly Wing, Lotus Leaf, Rice Leaf) and hydrophilic (Fish Scale, Snail Shell, Shark Skin) properties was divided in 4 and 3 respectively. Anti reflective coatings with self-cleaning properties have drowned considerable attention for both their basic appearances and vast applied usages. Antireflective coatings with self-cleaning properties have been considered because of their fascinating features and vast diversity of empirical uses.

Self-cleaning properties have received significant attention for the importance of their potential. Coatings at Nano-scales offer possibilities of using materials for self-cleaning surfaces. Recent efforts have begun to focus on the kinds of materials including metals, semiconductors and polymers. Such materials can have enormous potential in only a few applications. Moreover, the production of these materials requires high costs with low photo activity. In this regard, TiO 2 and its derived materials have shown acceptable and effective suggestions for this application. Moreover, the mechanism of self-cleaning has been explained by the effect of hydrophilic and hydrophobic. Hydrophilic and hydrophobic can have many applications in different areas like water purification, microfluidics and photovoltaic. In this review, the application of self-cleaning in solar cells and environment as well as TiO 2 derived materials and their applications in water management have been briefly illustrated. In addition, it has been explained that a huge number of self-cleaning materials, applications and improvement in utilities have been essential. In short, we have conducted a comprehensive review of the new approach and to mention numerous materials with hydrophobic and hydrophilic properties would be promising for most environmental concerns. Bio-inspired surface respond in nature through hydrophobic (Cicada Wing, Butterfly Wing, Lotus Leaf, Rice Leaf) and hydrophilic (Fish Scale, Snail Shell, Shark Skin) properties was divided in 4 and 3 respectively. Anti reflective coatings with self-cleaning properties have drowned considerable attention for both their basic appearances and vast applied usages. Antireflective coatings with self-cleaning properties have been considered because of their fascinating features and vast diversity of empirical uses.

Investigation of tribological behaviour of the hybrid composite, whose substrate is Al/Si alloy A356, reinforced with 10 wt. (%) of silicon carbide (SiC) and 0 and 5 wt. (%) of graphite (Gr) is presented in this paper by application of the Taguchi method. The composites are obtained by the compocasting procedure. The tribological investigations were realised on the tribometer with the block-on-disc contact pair in lubricating conditions and for the two values of the sliding speed, 0.25 and 1 m/s, two values of load 40 and 120 N and two values of the sliding path, 1200 and 2400 m. The wear traces were measured within the experiment, namely the wear intensities were calculated and results analysis was performed by application of the ANOVA technique. The strongest influence on the wear intensity was exhibited by the normal load (39.05%), then follow wt. (%) of the reinforcer (26.84%), the sliding speed (20.93%) and the sliding path (10.72%). The smallest wear appears in hybrid composite Al/SiC/Gr with 5 wt. (%) of the graphite reinforces, at the lowest load of 40 N, sliding speed of 1 m/s and along the sliding path of 2400 m. The main aim of their study is to provide new information and knowledge about the tribological behaviour of hybrid composites with a base of Al-Si alloy A356 reinforced with 10 wt. (%) SiC and with the addition of 0 and 5 wt.% Gr under lubricated sliding conditions.

Oil palm shells (OPS) has been used as an aggregate in concrete mixture, replacing the normal sense aggregate in many countries, since long time, and it is still an important aggregate in terms of quantity used. In Malaysia, the development of using oil palm shell as lightweight aggregate in construction industry, especially in structural application started about 30 years ago. Today; concrete is one of the most versatile construction materials. Many researchers found that OPS light weight concrete performances need to be enhanced especially when used for structural applications. In this research work an efforts were taken place to enhance OPS concrete performances by using bamboo fibers. Compressive strength, impact energy absorption and crack resistance were investigated for different mix design of bamboo fiber content and good results were gained. The compressive strength decreased marginally the percentage of bamboo fiber of 2% by cement weight. The impact energy absorption for 1% bamboo fiber increase about 1.9 times for service (first) crack and 1.5 times for the ultimate (failure) crack as compared to the service (first) crack and ultimate (failure) crack of the control sample with no bamboo fiber respectively. However, the impact energy absorption for 2% bamboo fiber increase considerably about 2.3 times for service (first) crack) and 1.8 times for the ultimate (failure) crack as compared to the service (first) crack and ultimate (failure) crack of the control sample with no bamboo fiber respectively. As such the 2% percentage of bamboo fiber has better performance than 1% percentage of bamboo fiber in term of impact energy absorption and crack resistance especially under service (first) crack condition. The difference in bamboo fiber length has only marginal effect on the impact energy absorption or surface crack resistance for service (first) crack and ultimate crack condition. The results show that oil palm shell light-weight concrete with bamboo fibers indicate a potential future of this material to be used as an impact resistance composite structures.

Abstract Background: Based on the empirical characteristics and weaknesses of the mixture design procedure of Marshall Procedure, the Strategic Highway Research Program (SHRP) developed a high performance of asphalt pavement layer (SUPERPAVE) with maximum density. For the attainment of the air voids on pavement could be CS and remained within the required limits that required a maximum compacting method on the concrete mixture with absolute density approach. Objective: The objective of the study was to analyze the amount of tensile strength of the super pave mixture with fiber reinforcement by indirect tensile strength test with the density and gyratory compaction approach. Methods: Number of collisions for absolute density was 2 x 400 collisions and the gyratory compactor was 1.250 of sloping angles. While, the variation of fibers length were 5 mm, 6 mm, 8 mm, 10 mm, 12 mm and 14 mm with temperature variation of 200C, 300C, 400C, 500C and 600C. The tests of elastic modulus and the Poisson’s ratio used indirect tensile test equipment. Results: The initial result of the Marshall mix design showed the Optimum Asphalt Content was 5.9%.The length of the optimum fibers was 8 mm with the elastic modulus of E = 2306735.04 Kpa; strain (Ɛ) = 0.0134287 for the density of 2 x 400 collisions and E = 2140563.34 Kpa with strain (Ɛ) = 0.0139791, for gyratory compactors with 1.25o turning angle. The superpave mixture by fiber reinforcement showed a more ductile mixture with a Possion ratio value of 0.42 compared to a Marshall mixture having a higher stiffness modulus with a Possion ratio of 0.39. Temperature decreased the elastic modulus, but the value of the Poisson ratio increased.
Key words: Refusal density, indirect tensile strength, gyratory

Low carbon steels (0.002-0.25%) account for a large proportion of the total output of steel. They are the most vital alloys used in petroleum and petrochemical industries since they account for over 98% of the construction materials. The wide application of low-carbon steel ranges from chemical, oil gas storage tanks and transportation pipelines are due to its moderate strength, good weld-ability and formability. However, the use of low carbon steel as construction material in industrial sectors has become a great challenge due to the effect of corrosion. This research work is focused on the comparative analysis of corrosion rate of low carbon steel in acidic environment. A low carbon steel of 0.145 weight percentage of carbon bought from a local market in Nigeria was used for this research work. The purchased low carbon steel sample was machined using lathe machine into cylindrical pieces of diameter of 25 mm and length of 60 mm and divided into four samples (Sample A, Sample B, Sample C, and Sample D). Four plastic bowls were filled with in traoxosulphate (vi) acid, hydrochloric acid, trioxosulphate (iv) acid, and ethanoic acid were used as acidic environment. The various steel samples were weighed with an analytical weighing balance before and after being immersed in the acidic environment in an interval of ten (10) days. The results obtained revealed that corrosion rate was comparatively high in the first twenty (20) days, and this was followed by continuous decrease in the corrosion rate of all the samples. However, the corrosion rate of the samples become partially uniform after thirty (30) days and the pattern remain the same for the remaining twenty (day 30-day 40) days and finally decreased gradually with subsequent increase in exposed acidic environment. More so, it was observed that samples soaked in the acidic solution of tetraoxosulphate (vi) acid shows a more aggressive corrosion rate as Manuscript History

Pembuatan material cutting tools dari alumina
aditif titania telah dilakukan. Aditif TiO2 dan TiC
pada alumina berfungsi meningkatkan kekuatan
mekanik. Komposisi material cutting tools
keramik dibentuk dengan cara press dan dibakar pada 2
variasi suhu pembakaran yaitu 1600C dan 1700C.
Pembakaran dilakukan dengan metode substitusi karbon yang
bersumber dari sagar silikon karbida yang bertujuan
mengubah TiO2 menjadi TiC. Berdasarkan hasil karakterisasi
yang dilakukan, bahan dengan komposisi 97% Al2O3, 3%
TiO2 yang dibakar pada suhu 1700C mempunyai sifat yang
lebih baik untuk dijadikan sebagai bahan cutting tools dengan
kekerasan (vickers hardness) 25,21GPa.
Kata Kunci: Alumina, TiO2, TiC, Cutting tools, Substitusi karbon