Copper doped polycrystalline silicon solar cell

Fabrication of improved performance photovoltaic cells is described. They are fabricated from polycrystalline silicon containing copper segregated at the grain boundaries

Characterization of grain boundaries in silicon

Zero-bias conductance and capacitance measurements at various temperatures were used to study trapped charges and potential barrier height at the boundaries. Deep-level transient spectroscopy (DLTS) was applied to measure the density of states at the boundary. A study of photoconductivity of grain boundaries in p-type silicon demonstrated the applicability of the technique in the measurement of minority carrier recombination velocity at the grain boundary. Enhanced diffusion of phosphorus at grain boundaries in three cast polycrystalline photovoltaic materials was studied. Enhancements for the three were the same, indicating that the properties of boundaries are similar, although grown by different techniques. Grain boundaries capable of enhancing the diffusion were found always to have strong recombination activities; the phenomena could be related to dangling bonds at the boundaries. Evidence that incoherent second-order twins of (111)/(115) type are diffusion-active is presented

Biocharcoal dari Kulit Kakao (Theobroma Cacao L)Untuk Mengadsorpsi Ion Logam Timbal Pb

Cacao is a commodity crop growth in the plantation farmers, particularly in Central Sulawesi. Processed of the cocoa fruits are mainly as the food products. Furthermore, the cocoa bark just become rubbish. This study aims to utilize the waste of cocoa bark to be used as biocharcoal to adsorb lead metal ions. The method used was spectrophotometry, where the lead ions concentration absorbed was measured using a Spectrodirect spectrophotometer. The results showed that at the optimum contact time 90 minutes, the lead ion capacity adsorption was 97% and the lead weight adsorbed was 25.26 mg/g. The optimum weight of 60 mg, where the lead ions capacity adsorption was 96.88% and the lead weight adsorbed was 25.22 mg/g. The optimum adsorption capacity was 40 ppm, where the lead ions adsorption obtained was 99.61% and the lead weight adsorbed was 10.84 mg/g

Application of STAD Type Cooperative Learning Models Integrated With Camtasia Studio Presentation Media on Student's Motivation and Learning Outcomes Class XI MIPA SMAN 1 Sigi Biromaru

This research aims to determine the effect of student motivation and outcomes learning through the application of cooperative learning model type of STAD combined with presentation media camtasia studio in class XI MIPA at SMAN 1 Sigi Biromaru. Subject of this research was two classes of XI MIPA1 as much 22 students as the experimental class and XI MIPA2 as much 22 students as a control class determined by Purposive Random Sampling. Data was collected use questionnaire instrument of learning motivation and learning result test. Testing data of research result using t-statistical analysis of t-test (Independent Sample t-Test) with prerequisite test that is normality test and homogeneity test. The average score of students learning motivation in the experimental class was 81 and the average score of students learning motivation in the control class was 67. The average score of students learning outcomes in the experimental class was 85 and the average score of students learning outcomes in the control class was 74. Based on the hypothesis analysis with t-test motivation of learning motivation obtained value tcount = 7.670 and it was located in the region of rejection of H0 between -2.018 and 2.018. Hypothesis analysis with t-test result statistic obtained value tcount = 8.056 and it was located in the region of rejection of H0 between -2,018 and 2.018. The result shows that there is effect of application cooperative learning model type of STAD combined with media presentation of studio camtasia toward the student motivation and outcomes learning in class XI MIPA at SMAN 1 Sigi Biromaru

Pengaruh Ekstrak Seledri (Apium Graveolens L.) terhadap Kelarutan Kalsium dalam Batu Ginjal

Celery (apium graveolens L.) contains chemicals that can be used as traditional medicine for various treatments. The research objective is to determine the effect of celery (apium graveolens L.) extractsin dissolving calcium kidney stones and calcium to determine the relationship between the concentration of extract of celery (apium graveolens L.) with the solubility of calcium in the kidney stones. Determination of the solubility of calcium in an extract of celery is by flame fotometer. The concentration of the extract was varried into 1, 5, 10, 15 and 20%. It showed that a concentration of 1% can dissolve the calcium as much as 15.104%; concentration of 5% can dissolve the calcium as much as 18.708%; concentration of 10% can dissolve the calcium as much as 23.683%; concentration of 15% can dissolve the calcium as much as 28.869%; and to a concentration of 20% can dissolve the calcium as much as 35.048%. It can be concluded that celeries extract can dissolve calcium of kidney stones

Plasma splashing from Al and Cu materials induced by and Nd : YAG pulsed laser

Plasma splashing from Al and Cu target materials and the growth of thin films on Cu and Al, respectively, has been studied using a Q-switched Nd:YAG laser with a 1064-nm, 80-mJ, 8-ns pulse width as the source of ablation. The target kept rotating and the substrate, Cu for Al and vice versa, was placed at an angle of 15° with respect to the beam axis. During the laser-matter interaction, the targets absorbed thermal energy within the thermal region depth of 4.7 (1.1) nm, yielding an ablated skin depth of 6.7 (4.2) nm. The surface morphology of the exposed targets was studied by analyzing SEM micrographs obtained using a ZEISS SUPRA 35 VP. The obtained results are explained on the basis of different sputtering/ablation mechanisms. Comparatively severe damage forming a bigger crater is seen on the Al target surface in contrast to the crater on the Cu surface. This observation is correlated with the blustering effect and/or debris formation. Energy dispersive spectroscopy (EDX) of the substrates yielded the deposition of micrometric grain-size particle

Sensitivity measurement of Fibre Bragg grating sensor

A practical pass-through type fibre Bragg grating (FBG) temperature sensor system have been designed, developed, simulated, and experimentally investigated. The performance of FBG was evaluated in harsh environments exposed under direct sunlight, rain, and wind. The sensor system designed directly focused with convex and hand lens. The temperature of FBG’s sensor head been measured. The broadband laser source was launched into the system using tunable laser source (TLS) and both transmission and reflection spectra of FBG sensor were measured by optical spectrum analyzer (OSA). Results shows that the Bragg wavelength shift, ΔλB increased proportionally with the temperature changes. The sensitivity of FBG were recorded at 0.0100 and 0.0132 nm °C-1 for the systems where convex and hand lens applied to the FBG’s sensor head respectively, while the sensitivity of 0.0118 nm °C-1 measured for the system without any focusing element applied