Measurement of low magnetic field has played an important role in many electronics applications such as navigation, military, non-destructive test, traffic detection as well as medical diagnosis and treatment. The presence of magnetic field, particularly its strength and direction, can be measured using magnetometer. There are many types of magnetometers being investigated through the years and one of the prominent types is fluxgate magnetometer. The main components of fluxgate magnetometer consisting of driving coils, sensing coils and magnetic core are developed by MEMS silicon processing technology. In this paper, an investigation on physical characteristics of the three-dimensional coil structure for a micro-scaled fluxgate magnetometer is presented. The physical characteristics such as width of the coil, distance between successive coils, and gap between the top and bottom coils which would influence the magnetic energy in magnetometer is discussed. In this work, finite-element method simulations to investigate the physical characteristics of the sensing coils were carried out, where the parameter of interest is the coils’ inductance as well as the magnetic flux density. Based on the simulation results, the varying of physical characteristics of the coils had its effects particularly in coil inductance, magnetic flux density, and magnetic energy. It could also be seen that the simulated results agreed with the theoretical aspects of magnetism in a coil. From the investigations, suitable coil dimensions were proposed.
Peat soil is characterized by its high content of decomposed organic matter. Majority of areas occupied by peatland have
been developed for agriculture sectors such as pineapple cultivation and oil palm. Due to its geotechnical drawback
characteristics such as highly compressibility and low shear strength, peat soil is classified as problematic soils and
unstable for engineering structures. Lack of suitable and expensive price of lands, peatland will be an alternative
option for future development. Prior to construction works, stabilization of peat soil should be performed to enhance
its engineering characteristics. This paper presents the effect of cement and curing period on engineering properties
of the cement-treated peat soil. Some engineering variables were examined including the compaction behaviour,
permeability and unconfined compressive strength (UCS). The Atterberg limit test was also carried out to examine
the influence of cement addition on peat soil. The cement-treated peat soils were prepared by adding varying amount
of ordinary Portland cement (OPC) ranging between 0% and 40% of dry weight of peat soil. In order to examine the
effect of curing, the treated samples were dried at room temperature for three and seven days while for UCS tests
samples were extended to 28 days prior to testings. The results showed that the liquid limit of treated soil decreased
with the increase of cement content. Maximum dry density (MDD) increased while optimum moisture content (OMC)
dropped with the increase in cement content. Permeability of treated soil decreased from 6.2×10-4 to 2.4×10-4 ms-1 as
cement content increase from 0% to 40%. In contrast, the UCS tests indicated an increase in uncompressive strength
with the increase in cement contents and curing period. The liquid limit and permeability were also altered as curing
periods were extended from three to seven days. This study concluded that geotechnical properties of peat soil can
be stabilized using ordinary cement and by modification of the curing periods.