Pengesan Optik, Piezoelektrik-fotoakustik

An optical detector based on piezoelectric detection of the photo acoustic effect in an absorbing metal plate is reported. Such a detector has been used in an experiment for measuring a Gaussian laser beam diameter using the knife-edge method. The responsivity of the detector varied from 4.05J.LV/mW at 68Hz to 1.25J.LV/mW at 211Hz. The Gaussian laser beam diameter obtained from the experimental data is (0.88 ± 0.02)mm and this value is comparable with the value stated in the laser specification note

Rekabentuk, Analisis Dan Perlaksanaan Sistem Ka Walan Meriam

Prestasi yang tinggi sistem kawalan meriam dipedukan bagi mengawal arah tembakan meriam. Sistem kawalan meriam terdiri daripada sistem ramal an arah meriam. Masa penerbangan iaitu masa yang diambil oleh peluru dan sasaran untuk tiba pada satu tempat yang dikenali sebagai titik pintasan. Algorithma ramal an telah dibangunkan menggunakan kaedah berangka yang akan menyesuaikan masa penerbangan dan arah tembakan meriam bagi mendapatkan ralat titik pintasan dalam julat yang boleh diterima atau b~rgantung kepada bilangan gelung yang telah ditetapkan. Arah meriam seterusnya dihantar kepada servo naikan dan azimut meriam bagi menghalakan meriam ke arah titik pintasan yang telah diramal. Daripada keputusan, didapati nisbah antara halaju sasaran dan halaju peluru pada muncung meriam yang kurang daripada\ud 0.6 diperlukan bagi mendapatkan keputusan ramalan yang sah dan bilangan gelung pengiraan yang optimum adalah 30. Performance of gun requires a reliable control system to control its aiming point. The control system for gun includes prediction of gun aiming point and time of flight i.e. time taken by a shell and a target to arrive at the same position which is known as point of intercept. The prediction algorithm has been developed using numerical method which tunes the time of flight and gun aiming point to obtain the point of intercept error within an acceptable maximum value or predetermined tuning iteration. The tuned aiming point is then transmitted to drive the gun elevation and azimuth servo in order to aim to the predicted point of intercept. From the result obtained, it is shown that a ratio between target velocity and gun muzzle velocity is less than 0.6 in order to get a valid prediction results and the optimum tuning iteration is 30

Independence from the perspective of the Shari'ah Committee

Purpose – Being the gatekeeper of Shari’ah compliance and holding the responsibilities to mitigate Shari’ah non-compliance risks are among the main roles of the Shari’ah Committee members. The purpose of this study is to gather perceptions of the Shari’ah Committee members on what and how they safeguard and strengthen their independence in fact and independence in appearance in practice. Design/methodology/approach – Data were gathered through semi-structured interviews that were conducted with thirteen Shari’ah Committee members from respective IFI. Findings – Based on the Islamic worldview and agency theory, the findings posited that safeguard measures within the context of Shari’ah Committee were strengthened by the presence of competencies, personal characters of the Shari’ah committee members, board engagement, role of chairman and accountability to God. Based on the theory, it was suggested that, the characteristics of Shari’ah committee and presence effective governance structure able to minimise threats to independence and enhance Shari’ah Committee effectiveness. Originality – This study contributes to the evidence on safeguard measures in Malaysian contexts that is highly regulated in governing Shari’ah governance practices in IFIs that could be considered by other Shari’ah Committees in different contexts. Practical implications – The insights from this study underlines other fit and proper criteria that need to be considered and enhanced to ensure the independence of the Shari’ah committee members when performing their roles and responsibilities for the IFIs. Besides, approaches of board engagement and Chairman involvement in overseeing the Shari’ah committee in discharging its duties able to improve its independence in fact and in appearance

Analysis of Pb(II) ion sensing by crosslinked chitosan thin film using surface plasmon resonance spectroscopy

The crosslinked chitosan thin film had been studied as a sensor element of surface plasmon resonance (SPR) optical sensor. Crosslinked chitosan solution was synthesized by homogeneous reaction of medium molecular weight chitosan in aqueous acetic acid solution with glutaraldehyde as crosslinking agent. It was deposited on gold film by spin coating. Using SPR technique, the optical properties of crosslinked chitosan thin film before and after contacting with different concentration of Pb(II) ion in a range of 0.5–100 ppm had been obtained by fitting. The resonance angle shifted to lower value as the Pb(II) ion concentration increased. Changes in the resonance angle (Δθ) are directly proportional to the concentration of Pb(II) ion solution. X-ray photoelectron spectroscopy (XPS) had been employed to confirm chemical elements and their bonding of the thin film prior to adsorption, as well as chemical interactions involved between Pb(II) ion and the thin film

Immobilization of tetrabutyl thiuram disulfide in chitosan thin film for sensing zinc ion using surface plasmon resonance spectroscopy

Tetrabutyl thiuram disulfide (TBTDS) immobilized in chitosan thin film has been studied as a sensor element for zinc ion, Zn2+, using surface plasmon resonance (SPR). The TBTDS-immobilized chitosan thin film, which acts as an active layer, was coated on a gold film by spin coating. Zn2+ can be detected by measuring the SPR signal when TBTDS-immobilized chitosan thin film contacts with Zn2+ in solution. The sensor produced a linear response for Zn2+ ranging from 0.1 to 1 ppm with a sensitivity of 0.0317 degrees ppm(-1). Using immobilized TBTDS as an active layer, the Zn2+ can also be selectively detected when present in mixtures of heavy metal ions

Measurement of the thermal diffusivity of materials by diverging thermal wave technique

The applications of diverging thermal wave technique to measure thermal diffusivities of materials are reported. In essence, the technique makes use of the information content of the thermal waves observed by means of a wide band infrared detector, that laterally displaced from the heat source, following pulsed laser excitation of the materials. Some observations obtained from aluminium, lead, graphite foil, and zirconium graphite samples are presented