Elasticity measurement using holographic interferometry double exposure technique

Holographic measurement of modulus elasticity was performed on samples of aluminum can. It is based upon the measurement of the displacement as a function number of fringes appeared on the body of the loaded can. The value of the modulus elasticity for the aluminum can is obtained as (1.00 ± 0.03) × 108 nm–2. This result is found in good agreement with a mechanical measurement by taking into account any experimental erro

Investigation of angular distribution on copper ions using faraday cup technique

A Q-switched Nd:YAG laser with fundamental wavelength of 1064 nm delivering pulse energy of 125 mJ and pulse duration of 8 ns was employed as a source of energy to generate plasma. The laser was focused on copper as a target material. The angular distribution of ejected ions species were collected by a developed Faraday cup. The cups were arranged radialy at the range of angles from 5o to 90o with two radiuses of 5 cm and 10 cm. The cups were coupled to high speed oscilloscope to display and measure the ion flux and charge state. The exposed Faraday cup was also studied by metallurgical technique. The results obtained show that the maximum flux of copper ion collected by Faraday cup was 11.7 x 1016 charge /sec. The maximum number of charge state was Cu+4 at 5 cm and Cu+3 at 10 cm. In general the angular distribution of ions flux is maximum in axial direction and decreases in radial direction. Various elements are found deposited on Faraday cup with majority lines of copper cluste

Whiting 1: the youngest globular cluster associated with the Sgr dSph

Recently, Carraro (2005) drew attention to the remarkable star cluster Whiting 1 by showing that it lies about 40 kpc from the Sun and is therefore unquestionably a member of the Galactic halo (b=-60.6 deg.). Its CMD indicated that Whiting 1 is very young (5 Gyrs) for a globular cluster. It is very likely that Whiting 1 originated in a dwarf galaxy that has since been disrupted by the Milky Way. Deep CCD photometry in the BVI pass-bands obtained with the VLT is used to improve the quality of the CMD and to determine the cluster's luminosity function and surface density profile. High-resolution spectrograms obtained with Magellan are used to measure the cluster's radial velocity and to place limits on its possible metallicity. The measurements of distance and radial velocity are used to test the cluster's membership in the stellar streams from the Sgr dSph. From our CMD of Whiting 1, we derive new estimates for the cluster's age (6.5 Gyrs), metallicity ([Fe/H]=-0.65), and distance (29.4 kpc). From echelle spectrograms of three stars, we obtain -130.6 km/s for the cluster's radial velocity and show from measurements of two infra-red CaII lines that the [Fe/H] of the cluster probably lies in the range -1.1 to -0.4. We demonstrate that the position of Whiting 1 on the sky, its distance from the Sun, and its radial velocity are identical to within the errors of both the theoretical predictions of the trailing stream of stars from the Sgr dSph galaxy and the previous observations of the M giant stars that delineate the streams. With the addition of Whiting 1, there is now strong evidence that 6 globular clusters formed within the Sgr dSph.Comment: 9 pages, 9 eps figures (some degraded in resolution), in press in Astronomy and Astrophysics. Abstract here below has been shortened to fit i

A simulation study of a parametric mixture model of three different distributions to analyze heterogeneous survival data

In this paper a simulation study of a parametric mixture model of three different distributions is considered to model heterogeneous survival data.Some properties of the proposed parametric mixture of Exponential, Gamma and Weibull are investigated.The Expectation Maximization Algorithm (EM) is implemented to estimate the maximum likelihood estimators of three different postulated parametric mixture model parameters.The simulations are performed by simulating data sampled from a population of three component parametric mixture of three different distributions, and the simulations are repeated 10, 30, 50, 100 and 500 times to investigate the consistency and stability of the EM scheme.The EM Algorithm scheme developed is able to estimate the parameters of the mixture which are very close to the parameters of the postulated model.The repetitions of the simulation give parameters closer and closer to the postulated models, as the number of repetitions increases, with relatively small standard errors

Optimization and Characterization of Lipase-Catalyzed Synthesis of Palm Amino Acid Surfactant

Optimization and characterization of lipase-catalyzed synthesis of palm amino acid surfactant was studied in 500 mL stirred tank reactor (STR). The reaction of palm kernel olein (PKO) and L(+)-lysine with Lipozyme RM IM as biocatalyst was optimized by response surface methodology (RSM). The study was divided into five parts which are; the optimization of reaction synthesis, the reactor study in term of mixing efficiency, the stability of immobilized enzyme, the purification process and the analysis and characterization of palm amino acid surfactant. A two level (24) full factorial central composite rotatable design (CCRD) was successfully employed for the experimental design and analysis of the results. The combined effect of temperature (XI); (40.0- 70.0°C), impeller speed (X2); (100.0-400.0 rpm), substrate molar ratio (X3); (1.0-4.0 mmol) and amount of enzyme (X4); (5.0-8.0 g) was investigated. The optimum condition derived via RSM at fixed reaction time of 24 h was successfully optimized at temperature; 47.50°C, impeller speed; 324.00 rpm, substrate ratio; 3.25 mmol and amount of enzyme; 7.25 g. The actual experimental yield was 89.03% under the optimum condition, which compared well with the maximum predicted value of 93.77%. Reactor study on the performance of 2 L STR as a mixing device was evaluated to improve the mixing efficiency. The reaction was scaled-up to 360X with a total volume of 1.125 L. The rheological property of the reaction mixture exhibited Newtonian behaviour. Rushton turbine impeller showed better performance in degree of mixing, whereby a high Reynold number for a range between 102 and 104 was achieved from 100-400 rpm, which exhibited a transitional flow pattern as compared to AL hydrofoil impeller. The Lipozyme RM IM was shown to be quite stable based on its synthetic activity where the percentage yield of palm amino acid surfactant was decreased only after 4 recycles in STR. The effect of shear forces due to the mechanical impeller speed on the enzyme morphology was determined by scanning electron microscope (SEM). The percentage yield of palm amino acid surfactant was found to be low for Rushton turbine impeller and AL hydrofoil impeller with speed of 400 rpm and 200-400 rpm, respectively.Purification process was successfully studied using liquid-liquid extraction technique, whereby high purity, 96.97% of palm amino acid surfactant was obtained. Analysis of the surfactant was determined by Fourier transform-infrared spectroscopy (FT-IR) and gas chromatography-flame ionization detector (GC-FID) to verify the identity and purity of the product isolated. Characteristics of palm amino acid surfactant were also examined, which include saponification value, acid value, iodine value and ester value Compatibility of the surfactant in most oils and its stability even after heating up to 90°C and overnight storage at room temperature showed that the surfactant has good potential to be used for further applications

Keselamatan dan orientasi laser

Buku ini mengandungi maklumat mengenai had sinaran dan jarak selamat bagi pendedahan penglihatan ke atas cahaya laser. Turut dimuatkan ialah keterangan bagi langkah-langkah untuk mencegah bahaya sinaran laser dan bekalan voltan tinggi. Ini disusuli pula dengan kaedah mengendalikan komponen optik yang dapat menjanakan kualiti cahaya yang baik. Sehubungan dengan ini, beberapa jenis material optik disenaraikan supaya pemilihan dapat dibuat bertepatan dengan spektrum laser yang digunakan. Kaedah mengorientasi laser melalui bantuan komponen optik yang sepadan turut dibincangkan. Pendek kata, buku ini merangkumi aspek-aspek keselamatan dan kaedah pengendalian laser yang dapat dimanfaatkan oleh semua pengguna laser yang meliputi pelajar, penyelidik di institusi pengajian tinggi, pengguna di industri, pengamal bidang perubatan, pertahanan, metrologi dan bidang-bidang lain yang terlibat secara langsung dalam pemakaian laser sebagai sumber tenaga

Shock Wave Emission during Cavitation Bubble Collapse in Free Liquid

Shock wave emission due to cavitation bubble collapse was studied. Four or five time collapses occurred in a single oscillation of a cavitation bubble. The secondary cavitation bubble appeared in the rebound process. When the cavity was split during the first collapse, double shock waves were radiated with separate centres in the following collapse. A gross distortion and multiple shock waves were radiated due to multiple breakdown

Kesan interaksi atribut persembahan multimedia, gaya kognitif, peringkat pengajian dan bidang pengajian ke atas daya ingatan visual pelajar IPT

Various multimedia presentation attributes contribute different positive effect on the visual recall memory due to factors such as different cognitive style, field of study and level of study. The positive effects could not be optimised if the most effective combination of the factors is not identified. This study aimed to identify the main effects and interaction effects of multimedia presentation format or attribute (line drawing pictures, black and white pictures, colour pictures, animation, animationaudio), cognitive styles (field dependence (FD), field independence (FI), level of study (year one, year three) and field of study (art-based, non-art-based) on the visual recall among students in higher education institutions (HEIs) in Malaysia. The sample consisted of 400 year one and three university students. This experimental study used 5 x 2 x 2 x 2 factorial design. The findings showed that the main effects of format of multimedia presentation, cognitive style, level of education and field of study on visual recall were significant. The results showed that students who viewed animated presentation obtained better mean scores on visual recall than students who viewed other presentation formats. Students with FI cognitive styles were found to recall better than the FD students, while students from non-art-based field obtained better scores than students from the art-based field. Year one students were found to have better visual recall than year three students. The interaction effect of format of multimedia presentation and level of education on visual recall was significant. The three-way interaction effect between cognitive styles, level of education and field of study as well as the interaction effect between format of multimedia presentation, level of education and field of study on visual recall were significant. Findings of the study support the effectiveness of multimedia presentation in enhancing the visual recall memory. However, the most effective attribute should be aligned with the students’ cognitive style, field of study and level of study so as to achieve the intended learning outcomes

A spectroscopic study of the globular Cluster NGC 4147

Indexación: Web of ScienceWe present the abundance analysis for a sample of 18 red giant branch stars in the metal-poor globular cluster NGC 4147 based on medium- and high-resolution spectra. This is the first extensive spectroscopic study of this cluster. We derive abundances of C, N, O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Y, Ba, and Eu. We find a metallicity of [Fe/H] = -1.84 +/- 0.02 and an alpha-enhancement of +0.38 +/- 0.05 (errors on the mean), typical of halo globular clusters in this metallicity regime. A significant spread is observed in the abundances of light elements C, N, O, Na, and Al. In particular, we found an Na-O anticorrelation and Na-Al correlation. The cluster contains only similar to 15 per cent of stars that belong to the first generation (Na-poor and O-rich). This implies that it suffered a severe mass-loss during its lifetime. Its [Ca/Fe] and [Ti/Fe] mean values agree better with the Galactic halo trend than with the trend of extragalactic environments at the cluster metallicity. This possibly suggests that NGC 4147 is a genuine Galactic object at odd with what claimed by some author that proposed the cluster to be member of the Sagittarius dwarf galaxy. An antirelation between the light s-process element Y and Na may also be present.https://academic.oup.com/mnras/article-lookup/doi/10.1093/mnras/stw114