Soils report Lab Example | Topics and Well Written Essays - 1250 words

Soils - Lab Report Example The moisture content at the boundary is normally defined as the water content at which the two halves of the soil cake will flow together for a distance of about half inch. The plasticity index on the other hand is the numerical difference between the liquid limit and the plastic limit and this number is normally dimensionless (Day, 2005). Both the liquid and the plastic limits are used to express the moisture content in the soil. The plasticity index is the difference between the liquid limit and the plastic limit. For the consolidation test, the pressure void relationship in the soil can be determined. This data is very important in the determination of the compression index of the soil and the pre-consolidation pressure (Day, 2005). Additionally, this data can be used o determine the coefficient of consolidation of the soil. The sieve test is carried out to determine the percentage of the different grains that are contained in the soil. The mechanical sieve analysis is carried out to determine the distribution of the coarse and the medium grained grains. It must be conducted within the ASTM D 422 - Standard Test Method for Particle-Size Analysis of Soils. The soil sample is weighed and recorded. The sizes of the particles are determined on a size with different sizes of the sieve holes. The soil is dried on an oven at a temperature of about 1050C -1100C. The weight of the dry soil is measured and recorded. The same procedure is repeated for the medium grained soil particles and the coarse grained particles for comparison. A sample of soil is taken and transferred to a glass plate. Water is added to the soil sample and mixed to for a paste. The soil paste is then placed in an airtight container. Using the penetration cone, the top surface of the soil is touched to and used as the starting point for the measurements. The dial gauge is then lowered to connect the cone shaft and the reading on the dial gauge is

Electromagnetic induction Essay Example | Topics and Well Written Essays - 1000 words

Electromagnetic induction - Essay Example Introduction Electromagnetic induction involves the electric current produced across a conductor that moves in a magnetic field. It is the basic operation for transformers, generators, electric motors, induction motors, solenoids, and synchronous motors. Electromagnetic induction is the process, which gives a prediction of the behaviour of the interaction between electric current and the magnetic field. Michael Faraday discovered the concept of induction in the year 1831. He stated that the produced electromotive force (emf) around a path that is closed is directly proportional to the magnetic flux rate of change through a surface that is path bounded. This implies that, there would be some induced electric current in a closed circuit whenever the flux going through a conductor bounded surface changes. This means that the conductor will be moving through it, or the field would be experiencing a change in its strength. Theory In Faraday’s initial demonstration of electromagneti c induction, two wires were wrapped around opposite sides of a ring of iron. According to his assessment, of the electromagnetic properties, he knew that whenever the currents began to flow in the first wire, a wave would move in the ring leading to an electrical effect on the side that was opposite. One wire was plugged into the galvanometer and observed during the connection into a battery. In this experiment transient currents were observed when the wire was connected to the battery and during disconnection. The observed induction was due to a magnetic flux change that happened when the battery was disconnected and connected. For many year, Faraday discovered different electromagnetic induction manifestation. For instance, transient currents were observed whenever a bar magnet was quickly slid inside and outside a wire coil thud generating Dc current through the rotation of a disk of copper next to a bar magnet having a sliding electrical lead. The explanation of electromagnetic induction according to Faraday was in terms of lines of force. Mathematically, the expression of Faraday can be written as; ?= - d?B/dt, where ? represents the electromagnetic force, and ?B represent the magnetic flux. In a case where there is a wire coil, having N loops with the same an equal area, the equation would be given by; ? = - N d?B/dt Whenever the Faraday’s law is combined with the Ohms law and Ampere’s law, a new law referred to as Lenz’s law would be generated. Faraday’s law is one equation having two phenomenons. The two phenomena include the EMF motion produced by a the force of magnetism through a moving wire and the EMF give out by an electric force as a result of magnetic field that is changing. Apparatus The apparatus for this experiment were coils, small compass, bar magnets, galvanometer, analogue multimeter, LV transformer, Dc voltage source, and LV transformer. Procedure Magnetic fields The outline of the two bar magnets were traced , and a small compass used to check the direction of the magnetic field at various points. The field direction was sketched in arrows to display the field direction. Two separate sketches were completed. One sketch involved attracting magnet where as the other one for a repelling magnet. The two sketches are displayed in diagram 1. Diagram 1 Attracting Magnets Repelling magnets Inductance The inductance for an air coil core was measured using the electronic bridge