The effect of morphology on the plasmonic sensing of the presence of formaldehyde in water by gold nanostructures has been investigated. The gold nanostructures with two different morphologies, namely spherical and rod, were prepared using a seed-mediated method. In typical results, it was found that the plasmonic properties of gold nanostructures were very sensitive to the presence of formaldehyde in their surrounding medium by showing the change in both the plasmonic peaks position and the intensity. Spherical nanoparticles (GNS), for example, indicated an increase in the sensitivity when the size was increased from 25 to 35 nm and dramatically decreased when the size was further increased. An m value, the ratio between plasmonic peak shift and refractive index change, as high as 36.5 nm/RIU (refractive index unit) was obtained so far. An expanded sensing mode to FD was obtained when gold nanostructures with nanorods morphology (GNR) were used because of the presence of two plasmonic modes for response probing. However, in the present study, effective plasmonic peak shift was not observed due to the intense plasmonic coupling of closely packed nanorod structures on the surface. Nevertheless, the present results at least provide a potential strategy for response enhancement via shape-effects. High performance plasmonic sensors could be obtained if controlled arrays of nanorods can be prepared on the surface.

Research on the sand iron potential in generating magnetite nanoparticles in Lampanah Aceh Besar through a study of techniques processing, synthesis methods and structural characteristics has been completed. The method used in this research is qualitative method in the kind of literature study from the data of Banda Aceh ESDM Ministry. The results of this study indicate that iron sand in Lampanah area has a dominant element which contained Fe3O4. The magnetic separation method is used to separate the iron sand from impurities, while the co-precipitation synthesis of one of the methods chosen in generating the magnetite nanoparticles which due to a simple, economical experimental process and low treatment temperature. Through the XRD test, the cubic iron sand magnetite nanoparticles with a 2 angle are 35,55o, 57,13o and 62,70o with the hkl [311], [511] and [440], while the TEM and SEM tests showed that the dominant particle shape is round and the distribution is tight. Therefore, controlling the size and shape of iron sand magnetite nanoparticles will provide great potential in the magnetic field of magnetism. The conclusions of this study show that the iron sand located in Aceh Besar has the potential to be a magnetite nanoparticle.

This paper reports a study on plasmonic properties of gold nanoparticles to detect the presence of formaldehyde solution in water. Gold nanoparticles were grown on substrates by the seed mediated growth method. A sensor system was setup, comprises a light source, a dual arm fibre optic probe, a spectrometer and sensor chamber. The detection of formaldehyde was done by comparing the Localized Surface Plasmon Resonance (LSPR) spectra of gold nanoparticles samples immersed in the deionised water and formaldehyde solution. It was observed that the peak position LSPR spectra of nanogold samples and their intensity were change by the presence formaldehyde. The difference between resonance peak intensity of LSPR spectra gold nanoparticles sample in formaldehyde solution and water can be used as sensing sensitivity parameter of the sensor. It was found that the sensing sensitivity is increase with the size of nanoparticles until it reach the optimum particles size.

This study aims to determine the effect of the application of the GQGA (Giving Question and Getting Answer) learning model to the learning outcomes of Biology students in class X MIPA SMAN 1 Payakumbuh District. This research is a quantitative study, using quasi-experimental methods (quasi experiment) with Randomized posstest only control design. The study population was students. Obtaining samples with random sampling techniques. Based on these techniques, obtained class X MIPA 1 as an experimental class of 22 samples and class X MIPA 2 as a control class of 25 samples. Data analysis technique was performed using t-test with α = 0.05. The results of data analysis obtained t-count = 2.52 ˃ t-table = 1.67 at 95% confidence level, which means the hypothesis is accepted, which means that there is an influence of GQGA learning models on student Biology learning outcomes. The conclusion of the application of the GQGA learning model has a significant influence on student Biology learning outcomes. Keywords: ecology, giving question and getting answer (GQGA), learning model

The purpose of this study is to produce valid and practical guided inquiry based Biology LKS. This type of research is research and development. In this study, researchers used the development method using a 4-D model (four D), defining, designing, developing and disseminating. Guided Biological LKS based on valid inquiry, then tested in a limited way in MAN 3 Payakumbuh for students of class XI MIA. To see the practicality of Biology LKS, researchers used a questionnaire response sheet given to teachers and students. , resulting in an average percentage of 81.98% which belongs to a very valid category. The results of processing data from the practicality questionnaire the teacher's response obtained an average yield of 88.2% with a very practical category and the practicality of the student's response to an average of 81.9% with a very practical category. Conclusion, the development of guided inquiry-based Biology LKS material is a very practical regulatory system used for the learning process. Keywords: guided inquiry, LKS, regulation system