Simulation of settlement due to wetting of normally consolidated unsaturated clay layer

Anuchit Uchaipichat

Almost 40 percent of natural soils on the earth surface are in an unsaturated state. The settlement due to wetting of unsaturated soil layer affects building structures situated in the arid areas. Thus, this paper presents the simulations of settlement due to wetting of normally consolidated clay layer with the initial matric suction ranging from 50 to 300 kPa. The simulations were performed using the elasto-plastic model for unsaturated soils based on effective stress principle. The model simulations were conducted by expressing the governing equations of the model and were then solved as a series of initial value problems. The simulation results show that the compression occurs during wetting the normally consolidated clay to saturated state for all values of initial matric suction. The settlement, which was obtained by converting the volumetric strain to the settlement of clay layer with thickness of 5 m, increased with decreasing matric suction. Furthermore, the settlement due to wetting to saturated state increased with the initial matric suction.

The study of the thermal profile of a three-phase motor under different conditions

J. G. Fantidis, K. Karakoulidis, G. Lazidis, C. Potolias and D. V. Bandekas

Infrared thermography is one of the most cost-effective predictive maintenance technologies which are quickly, accurately available without interrupting the operations and locate problems in various types of systems before any failure. Electrical thermography is the most widely performed application of Infrared thermography. It is used virtually around the world to evaluate the condition of electrical systems and equipment. Thermal imaging can help someone to track the temperature at which any electrical motor is operating, which is crucial to the longevity of the motor. This article deals with the temperature measurements on an induction motor and describes the influence of parameters such as the relative humidity and the environmental temperature on the measured values.

Fuel properties of jatropha methyl ester and its blends with petroleum diesel

Jerekias Gandure, Clever Ketlogetswe and Abraham Temu

Jatropha curcas has drawn the attention of researchers in recent times as a high potential substrate for production of biodiesel. However, like many other substrates, fuel properties of its biodiesel vary with such factors as growing and climatic conditions. This paper presents experimental results for jatropha methyl ester of Botswana’s semi-arid climatic conditions. Physicochemical properties, performance and emissions characteristics of jatropha methyl ester and its blends with petroleum diesel were investigated experimentally. The results showed that viscosity values for all fuels fall within specifications of American Standard Test Methods (ASTM), with a maximum variation of 21% observed between B0 and B100. Cold flow properties of cloud and pour points indicate that jatropha methyl ester and its blends can power the diesel engine without much difficulty in cold weather. The flash points of jatropha methyl ester and its blends were found to be lower than the ASTM specification of a minimum of 130oC, implying that the fuels are highly flammable and need extreme handling precaution during transportation. Biofuels depicted better engine performance when compared to petroleum diesel in terms of brake power, specific fuel consumption (SFC) and brake thermal efficiency (BTE). This is largely attributed to higher combustion efficiency due to extra inbound oxygen. Higher combustion efficiency of biofuels led to reduced production of hydrocarbons (HC), carbon monoxide (CO) and carbon dioxide (CO2) emissions when compared with petroleum diesel. Petroleum diesel was also observed to produce the highest proportion of soot during combustion in the magnitude of approximately 3% per 3ml of fuel.

Human recognition using biometric authentication system

M. Jasmine Pemeena Priyadarsini, K. Murugesan, Srinivasa Rao Inbathini and A. Arun Kumar

A model is designed to work for Face recognition, Finger Print recognition, and Signature recognition for recognizing the individual person test images out of training images. There are various methods for recognition and images need to have good sensor quality. A Fisher LDA approach which produces a set of Eigen faces and fisher faces to obtain projected images has been implemented. In this paper both PCA and LDA techniques have been used. Minutiae matching algorithm which after several preprocessing stages produces minutiae points on finger print has been implemented. The offline signature is taken for verification and recognition system; Global features are extracted and matched. A set of fisher images are projected and reconstructed. The test image is also projected and a minimum error reconstruction value is calculated. If error is less than a threshold value, then it recognizes the face from the database. A set of false minutia points are extracted and efficiently the minutia points are removed from the finger and made into a template and verification is done with other template for producing percentage score of the matching template. After extracting Global features from the signature, the same steps are applied for the input signature and matched with the database of signature images. Multimodal biometric authentication is applied for verification and identification of humans where same the human being database is matched with the input image.

A comparative study of brick and straw bale wall systems from environmental, economical and energy perspectives

Larisa Brojan, Alja Petric and Peggi L.Clouston

Abstract:

The aim of this study is to compare brick and straw bale wall systems from environmental, economic and energy perspectives. The choice of basic building materials is an important part of each project and is usually based on professional judgment, taking into consideration the importance of various criteria such as economic, environmental, functional, aesthetic and health aspects. Brick is the most commonly used building material worldwide; whereas straw, though widely available and having many advantageous properties, is still poorly exploited. In this study, wall compositions of both materials were examined assuming passive building standards. Three values - Global warming Potential (GWP), Primary Energy Input (PEI) and Acidification Potential (AP) - of environmental impact were calculated. It was shown that, considering environmental, economic and energy values, the use of straw bales is a good alternative to brick.

Characterization of clays for making ceramic pots and water filters at Mukondeni village, Limpopo province, south Africa

F. Amponsah-Dacostab C. Muzerengib S.E. Mhlongo and G.F. Mukwevho

Abstract:

Clay is a raw material that has many uses across the different industries. The principal use of clay at Mukondeni Village is making of pots, which are based on traditional paintings of Venda and Tsonga people and are sold to tourists, businesses and local people. Although the knowledge of using raw clay for making of ceramic pots is known to many throughout the world; very little scientific studies have been conducted to establish the basic characteristics of clays for this purpose. The main aim of this study was to characterize the Mukondeni clay deposit based on its mineralogical, geochemical and physical properties. The mineralogical and chemical characteristics of the clays were determined using XRD and XRF respectively. Atterberg limits tests were conducted in order to establish the physical properties of the clays. The XRD results indicated that the gritty reddish clay (RCSH) has the least amount of smectite (37.7%) while in smooth greenish (GCSH) and black (BCSH) it was found to be up to 55.69% and 55.08% respectively. Although all clays indicated elevated SiO and Al₂O₃ concentration, the RCSH had the highest (66 % silica and 16.07% Al₂O3) with the least LOI percentage (4.39%). On the other hand, the trace element results showed the clays to be having high concentration of Cr (±888.33 ppm), Ni (±343.30 ppm), V (±118.86 ppm) and Zn (±50.66 ppm). Among all the Mukondeni clays, the GCSH had the highest plastic index of 20; indicating that it is highly plastic than the RCSG (5) and the GCSH (6.3). It was found that the clays smectite content that black and green clays are generally highly plastic, sticky and less porous than red clay. As a result, the two clays (black and green) were considered unsuitable for making ceramic pots and water filters since they have high potential of cracking during the drying up process. It was recommended that the potters mix the red clay with the other two clays to improve their molding and overall pots making properties.

Sorption of cadmium from water using neutralized red mud and activated neutralized red mud

Veselinka V. Grudić, Snežana Brašanac, Vesna L. Vukašinović-Pešić and Nada Z. Blagojević

In this study seawater-neutralized red mud (Bauxsol) and Bauxsol which is acid treated (aBauxsol) and acid-heat treated (AB) were used as adsorbents for removing of Cd (II) from water. Batch sorption experiments were carried out to investigate the sorption of Cd (II) to the sorbents with particular focus on sorption kinetics, sorption capacity and isotherms. The sorption equilibrium data for present sorbent/sorbate system were tested by both Langmuir and Freundlich models. The values of ΔG° for Cd (II) ion indicate that the adsorption process is spontaneous. Pseudo-second order kinetic model provided a perfect fit for the kinetic data of Cd (II) sorption. Based on the sorption and kinetic information obtained for Cd (II) removal by these sorbents, it may be concluded that AB are the most effective sorbent for Cd (II).

Highly nonlinear square lattice photonic crystal fiber with negative dispersion

S. Revathi, Srinivasa Rao Inbathini and A. Amir

Abstract:

A solid-core square lattice square photonic crystal fiber is modeled by removing four air-holes at the center region is proposed in this paper. Various characteristics are observed for a wavelength range of 1150 to 1750 nm. Negative dispersion, low confinement loss, small effective area and high nonlinearity are obtained. Negative dispersion of -300 ps/nm/km for Λ= 0.5, low confinement loss of 10^-10 db/m and a high value of nonlinearity around 110w¹km^-1 at 1550nm wavelength for Λ= 0.9 is observed. Birefringence w value of around 10^-4 is obtained. Proposed PCF can be suitable for dispersion compensation and non linear applications.

Modelling and simulation of matlab/simulink based lookup table model of solar photovoltaic module

malathy S and Ramaprabha R.

Abstract:

This paper proposes lookup Table (LUT) based model for solar photovoltaic (PV) module. The performance of a solar PV module is greatly influenced by insolation level and temperature. The experimental data including voltage and current of the PV module are obtained for various insolation conditions. These data are then used to develop a look up Table to mimic the behaviour of the actual PV module. To ensure that the maximum power is transferred from the PV module to the load, maximum power point tracking (MPPT) algorithm is usually employed. The paper also proposes LUT based MPPT to track the optimal operating point whenever the insolation changes. The V-I and V-P characteristics obtained from the look up Table based Matlab/Simulink model and the conventional model (five parameter model) are compared and the results are validated with the experimental data.

Effect of partial replacement of granite with washed gravel on the characteristic strength and workability of concrete

C. B. Echeta, E. E. Ikponmwosa and A. O. Fadipe

Abstract:

In this paper, the effects of partial replacement of crushed granite as coarse aggregate with washed gravel on the strength and workability of concrete are reported. 1:2:4 concrete mix (Cement: Fine Aggregate: Coarse Aggregate) was used, with a water/cement ratio of 0.65. Six batches of concrete were produced in which the granite was progressively replaced with washed gravel at intervals of 20 percent, from 0% to 100% replacement level. (0% replacement was the control). Twelve (12) nos. 150x150x150 mm concrete cubes were cast from each batch and cured in a water tank at room temperature. The cubes were crushed for strength in sets of three at curing ages of 7, 14, 21, and 28 days respectively. A slump test was carried out on each batch. It was observed that the workability of the concrete decreased with increase in gravel content. Also, it was observed that for all curing ages, as the percentage replacement level increased, the compressive strength of the concrete increased to a maximum at 20 percent replacement level. Thereafter, it decreased as the replacement level increased to 100%. The maximum 28-day compressive strength at 20% replacement level was 37.2 N/mm²; indicating a 54% increase when compared to the 28-day strength of the control mix (24.2 N/mm²). The results also showed that the 28-day strengths of 100% granite concrete and 100% gravel concrete were comparable.

Design and development of a pc-based automated data logging system for measuring temperature

Md. Abdullah Al Mamun, Kenneth Sundaraj, N. Ahmed, Matiur Rahman, Mijanur Rahman and Nizam Uddin Ahamed

Currently, accurate information of the temperature over time is required in medical, scientific, and various industrial applications. The objective of this work was to design and develop a fully automated microcontroller-based data logging system to measure the temperature in a working environment. The system consists of a temperature sensor (LM35), a data logger with a memory card, and a high-performance low-power AVR 8-bit microcontroller (ATMega-8). The system consisted of LCD monitoring device and a computer terminal for storing and displaying the data. A simple and user friendly graphical user interface (GUI) was developed using the LabVIEW software package and connected with the data acquisition system. This inexpensive real-time system was preliminary tested in a room, and the data were obtained from the LCD display without any problems. In addition, it was verified that the data were sequentially stored in the memory. The observed data are comparable with data measured using a conventional mercury thermometer. The developed system can be used in many areas, including personal bedrooms, industrial settings (particularly dairy, fuel, and agricultural), shipping containers, medical applications, and any place where the temperature needs to be recorded and monitored. In conclusion, the developed system is easy to use, requires no additional hardware, and permits the selection of the amount of data and the time intervals between the data recordings. In addition, the collected data can easily be transferred to a computer via a connected serial port.

In this paper, the dispersion of a solute in the peristaltic flow of a Jeffrey fluid in the presence of magnetic field with both homogeneous and heterogeneous chemical reactions has been discussed. The average effective dispersion co-efficient has been found using Taylor's limiting condition under long wavelength approximation. It is observed that the average dispersion co-efficient decreases with Jeffrey parameter  and magnetic parameter M in the cases of both homogeneous and combined homogeneous and heterogeneous chemical reactions. But, it increases with amplitude ratio which implies that dispersion is more in the presence of peristalsis. Further, dispersion decreases with homogeneous reaction rate parameter and heterogeneous chemical reaction rate parameter.