Pearl shells (pinctada maxima) are the superior commodities in West Nusa Tenggara Province. The shellfish is utilized as a producer of pearls while the waste of pearl shells has not been widely used by the community. Main composition of fhe pearl shells is calcium. CaO content was tested using AAS and obtained CaO in shells as much as 52.23%. CaO is used as a source of hydroxyapatite (HAp). Shellfish powder is synthesized with H3PO4 compound. Synthesis is conducted by precipitation method. Synthesis results were analyzed utilizing XRD and FTIR. From the examination, HAp compounds were identified. Group of PO43, CO32, and OH are constituent groups of HAp compounds. Moreover, another calcium phosphate is formed  namely TCP. This HAp compound has a maximum crystallinity of 78.33% at an angle of 77.18 °. The smallest HAp particle size at an angle of 31.92 ° is 1.4 μm. The degree of high crystallinity is influenced by high intensity and a wide FWHM. Meanwhile, the small molecule size is acquired on a wide FWHM with a small Bragg angle position.

Lead (Pb) is a dangerous heavy metal that can settle in marine animals, and it will have a bad impact on our health. One of the efforts to reduce the stream’s levels of hazardous metals is by using the adsorption method. This study aimed to determine the effect of CaO doping on activated carbon composites on the physical properties of water and its ability to absorb Pb. Atomic Absorption Spectroscopy was conducted to determine the remaining Pb content after the adsorption process. Based on the results, it was found that the doping of CaO in activated carbon composites affected the physical properties of water-based on parameters of pH, EC, TDS, temperature, and turbidity. The water quality test results have met the PerMenKes standard No: 416/MENKES/PER/IX/1990, with the water quality obtained having a pH value of 7, EC 313.00 µs/cm, TDS 156.50 ppm, temperature 29 , and turbidity 3.95 NTU. Besides that, the addition of CaO mass to activated carbon composites affects Pb metal’s adsorption ability, where CaO doping can increase the absorption of Pb.

Highlight Research New method to synthesis nano chitosan from Vannamei shrimp with high Deacetylation Degree Nano chitosan from Vannamei shrimp can adsorb heavy metal Fe up to 81.35% Shrimp shells as an alternative adsorbents for Fe   Abstract Shrimp cultivation produces shrimp wastes in several forms, including shells from the molting process. Shrimp shell waste can be used as a source of nano chitosan. Many researches have used nano chitosan for various applications, one of which is to adsorb heavy metal pollution. This present study aimed to extract chitosan from shrimp shells and investigate the ability of nano chitosan to adsorb Fe metal. The research began by isolating chitin and chitosan from shrimp shells through deproteinization, demineralization, and deacetylation. The obtained chitosan was afterward characterized using Fourier Transform Infrared (FTIR). Furthermore, the glassy ionic method was used to synthesize nano chitosan. Nano chitosan was characterized using a scanning electron microscope (SEM), and the Fe metal adsorption ability was measured using Atomic Absorption Spectroscopy (AAS). The FTIR results showed that the synthesized shrimp shells had successfully formed chitin compounds with the appearance of the C-O-C functional group, while the chitosan compounds with the appearance of O-H and N-H groups. The SEM characterization showed that nano chitosan with a size of 173.71 nm was successfully formed with identical morphology in the form of a flat (spherical), elongated, and irregular position. The nano chitosan was able to absorb Fe solution up to 81.35%. Therefore, nano chitosan from the shrimp shells is suitable as an adsorbent of heavy metal Fe.

Inovasi pembuatan pakan ternak dalam sediaan wafer perlu dilakukan untuk menjadi alternatif pakan saat musim kemarau. Limbah tahu merupakan salah satu bahan dasar yang dimanfaatkan sebagai bahan pembuatan wafer. Tujuan penelitian ini untuk mengidentifikasi perlakuan yang direkomendasikan dalam pembuatan kandidat wafer berdasarkan karakteristik fisis wafer. Kandidat wafer ditinjau berdasarkan warna, kadar air, densitas wafer, densitas partikel, dan porositas.  Proses pembuatan wafer dilakukan dengan proses pemadatan dan pemanasan. Sebelum serbuk limbah tahu dicetak, dipastikan dahulu kadar air pada serbuk limbah tahu sesuai dengan stadar SNI 3148:2:200. Suhu pemanasan serbuk limbah tahu yang direkomendasikan menggunakan suhu 100oC. Karakteristik serbuk limbah tahu yang dihasilkan yaitu serbuk berwarna putih, kadar air sebesar 14,1% dengan nilai densitas partikel serbuk limbah tahu(𝜌sa ) 0,189g/cm3 serta porositas (𝜙sa ) 0,216%. Sedangkan untuk proses pencetakan wafer, suhu pemanasan yang direkomendasikan yaitu 70oC. Kandidat wafer yang diperoleh menghasilkan warna putih, tahan hingga 4 minggu, kadar air 7,19%, densitas partikel (𝜌p ) 0,254 g/cm3, densitas wafer 1,10 g/cm3 dan porositas 𝜙w sebesar 3,47±0,0118%.

Heat transfer is a physical phenomenon that is widely applied in the fields of aerospace, industrial, nuclear, power generation, and automotive. Simulations can be done to better understand the phenomenon of heat transfer in order to save costs and risks that arise. The heat transfer profile in a two-dimensional multilayered composite cylinder has been successfully determined using analytical and numerical methods. Temperature distribution profiles in different times and different thermal diffusivity for the two layers have been successfully calculated using Python 3.7 with the Numpy library.