Open Access Case study

Analysis of Near Surface Seismic Refraction for Geotechnical Parameters in Opolo, Yenagoa of Bayelsa State

Francis Omonefe, Eteh Desmond, Oborie Ebiegberi, Oboshenure Kingsley Karo

Journal of Engineering Research and Reports, Page 1-12
DOI: 10.9734/jerr/2019/v4i416910

Three surface refraction seismic profiles were conducted in a site targeted for huge construction in an underdeveloped area in Opolo, Yenagoa city to portray some of the subsurface soil engineering characteristics for the purposes of construction. The Generalized Reciprocal Method (GRM) was used to interpret the acquired P and S-wave. Various shallow rock engineering parameters such as Oedometric modulus, Concentration Index, Material Index, Lame’s constant, Density Gradient, Stress Ratio, Shear modulus, Bearing capacity, and N-value were calculated in other to assess the strength of the subsurface  from a geophysical and engineering perspective. The values from the seismic velocity and strength parameters indicates that the bedrock layer (layer 3) of the area studied is characterized by more competent rock quality than layer 1 and 2. Hence, the Opolo site is suggested for construction activities with percussive measures.

Open Access Original Research Article

Differential Active Balun Design for WiMAX Applications

Frederick Ray I. Gomez, John Richard E. Hizon, Maria Theresa G. De Leon

Journal of Engineering Research and Reports, Page 1-8
DOI: 10.9734/jerr/2019/v4i416908

The paper presents a design and simulation study of a differential active balun circuit implemented in a standard 90 nm complementary metal-oxide semiconductor (CMOS) process.  The active balun design is intended for Worldwide Interoperability for Microwave Access (WiMAX) applications operating at frequency 5.8 GHz and with supply voltage of 1V.  Measurements are taken for parameters such as gain difference, phase difference, and noise figure.  The differential active balun design achieved gain difference of less than 0.23 dB, phase difference of 180° ± 3.4°, and noise figure of 9.78 dB, which are comparable to past active balun designs and researches.  Lastly, the design achieved a low power consumption of 3.6 mW.

Open Access Original Research Article

Development of a Single Wheel Test Rig for Measuring Motion Resistance

A. M. Sedara

Journal of Engineering Research and Reports, Page 1-13
DOI: 10.9734/jerr/2019/v4i416909

Research on soil-wheel interaction is essential in studies of motion resistance of narrow wheels of agricultural machines. The aim of this research was to study the effects of soil moisture content and tyre inflation pressure on motion resistance of narrow wheels using a locally developed single wheel test rig. A single wheel Test Rig facility was developed at Federal University of Technology, Akure. It consists of a soil bin, carriage, single narrow wheel tester, trolley and drive system. An existing indoor soil bin facility was equipped with a soil bin which dimension was 9.76 m length x 1.98 m width x 0.92 m high. The single-wheel test facility was utilized to investigate the effect of tyre inflation pressure and vertical load on motion resistance of wheel. Two narrow wheels of 90/10-10 in width, IRC MB90 tyre were used as the test wheels on clay soil and were separately installed on a carriage that traversed the length of soil bin. Two inflation pressures of 274 kPa and 380 kPa and four levels of vertical load applied on wheel (i.e. 15, 20, 30, and 40 kg) were examined at two different soil moisture conditions (bulk density of 1.58 g/cm3 and 1.55 g/cm3, soil moisture content of 8% and 10% dry basis and soil penetration resistance of 1.02 MPa and 1.5 MPa). Exponential regression was obtained for the two wheels to check for linearity at different moisture content, R2value for test wheel 1 with inflation pressure of 270 kPa at 8% moisture content was 0.9974 while that of inflation pressure of 380 kPa at 10% moisture content was 0.9952; also for test wheel two (2) R2 value was 0.9977 and 0.9914 at moisture content of 8% and 10% respectively, this shows for test wheel 1 with inflation pressure of 270 kPa at 8% moisture content showed more motion resistance compared to motion resistance of test wheel 1 at inflation pressure of 380 kPa and 10% moisture content, while for test wheel 2 with inflation pressure of 270 kPa showed low motion resistance at 8% motion content. The effect of different inflation pressures and vertical loads on the motion resistance of the narrow wheels has been investigated under different moisture content (8% and 10%). The contact area for all tests was in the range of 309-330 cm2, average contact pressure increased nearly linearly with increase in vertical load and increase in inflation pressure The research provides data that are relevant in the study of soil-wheel interaction.

Open Access Original Research Article

EdDSA Over Galois Field GF(p^m) for Multimedia Data

Y. N. Shivani, A. Srinivas, B. K. Thanmayi, V. Vignesh, B. V. Srividya

Journal of Engineering Research and Reports, Page 1-7
DOI: 10.9734/jerr/2019/v4i416911

The Edwards-curve Digital Signature Algorithm (EdDSA) was proposed to perform fast public-key digital signatures and thus replace the Elliptic-Curve Digital Signature Algorithm. Its key advantages over the latter include higher performance and straightforward, secure implementation for embedded devices. EdDSA algorithm is implemented over Galois Field. The operations like addition and multiplication in Galois field are different compared to normal addition and multiplication. Hence implementing EdDSA over Galois field provides more security compared to the conventional EdDSA signature. The basics of Galois Field and its application to store data is introduced. The finite field GF (pm) is an indispensable mathematical tool for some research fields such as information coding, cryptology, theory and application of network coding.

Open Access Review Article

A Review of Soil Dynamics in Traction Studies

A. M. Sedara

Journal of Engineering Research and Reports, Page 1-13
DOI: 10.9734/jerr/2019/v4i416912

As the world population increases more than ever before and increasing demand on food, feed and fiber, and security, the number of off-the-road vehicles is rapidly increasing for agriculture, forestry, military, mining and construction industries. Many researchers have studied and still investigating traction as it relates off-road vehicles and publications abound especially from developed countries of Europe, America and others.  In our generation scientists are trying to put robotic vehicles on the lunar and Martian terrains. This trend makes the study of soil dynamics in traction a sine qua non in our tertiary and research institutions. In Nigeria there is a dearth of publications in this specialized area of study. This is a review paper and the purpose is to highlight some of the studies that have been conducted over the years, with a view to enlightening, encouraging, stimulating and challenging would be researchers. Trends in the development of soil bin with single wheel testers were reviewed including tractive and transport devices used in them. Traction parameters including motion resistance, measurement and data acquisition systems, traction predictive equations including wheel numeric and mobility numbers were also reviewed. Efforts made in the development of soil bin for soil dynamics research and further research interest at the Federal University of Technology, Akure (FUTA) were highlighted.