Judul: Synthesis and Analysis of the Mechanical Properties of Palm Oil Empty Fruit Sandwich Biocomposites (OPEFB)
Abstrak: Tandan Kosong Kelapa Sawit (TKKS) merupakan limbah padat pengolahan minyak kelapa sawit. TKKS utuh diproses menjadi benang pilin. Benang dianyam menggunakan anyaman tradisional dan ditenun menggunakan Alat Tenun Bukan Mesin (ATBM) hingga terbentuk kain woven. Kain woven disusun berdasarkan biokomposit sandwich menggunakan hot press dengan variasi komposisi kain sawit, kevlar-sawit dan kevlar. Pengujian mekanik dilakukan dengan dua tahap yaitu tensile strength dan izod impact strength. Pengujian kuat tarik untuk mengetahui nilai tensile strength, elongation at break dan modulus young. Sampel variasi kain sawit dengan susunan lapisan kain kevlar satu lapis, 8 kain kevlar-sawit, dan kain kevlar satu lapis memiliki nilai kuat tarik rata-rata paling besar yaitu 35,57 MPa dengan luas permukaan 110 mm2. Sampel variasi kain sawit dengan susunan komposit kain kevlar-sawit dan kevlar-sawit satu lapis memiliki nilai impact strength terbesar 322 J/m. Energi kinetik yang terjadi sebelum tumbukan 0,63 J dan momentum sebelum tumbukan 2,1 kg.m/s. Sesudah terjadi tumbukan energi kinetik yang dihasilkan 0 J tepat pada jarak 5 mm., Oil palm empty fruit bunches (OPEFB) are one of the solid wastes from palm oil processing. The whole OPEFB was processed into a twisted thread. The thread is woven using traditional weaving and woven using a non-machine loom to form a woven cloth. Woven fabrics are prepared based on sandwich biocomposites using the hot press method, with variations in the composition of palm, kevlar-palm, and kevlar fabrics. Mechanical testing is carried out in two stages, namely the tensile strength test and the impact test. Tensile strength testing was carried out to determine the values of tensile strength, elongation at break, and Young's modulus. Samples with variations of palm cloth with one layer of kevlar cloth, 8 layers of kevlar-palm cloth, and one layer of kevlar cloth have the highest average tensile strength value among the other samples, namely 35,57 MPa with a surface area of 110 mm2. Samples with variations of palm cloth and a one layer kevlar-palm and kevlar-palm palm fabric composite had the highest impact strength value of 322 J/m. The kinetic energy that occurs before the collision (Ek) is 0,63 J, and the momentum before the collision (P) is 2,1 kg/s. After the collision, the kinetic energy produced is 0 J at an exact distance of 5 mm.
Keyword: biocomposite sandwich, izod impact strength, OPEFB, tensile strength

Judul: The Effect of Oil Palm Empty Bunch (OPEB) Filler on the Mechanical Properties of Natural and Synthetic Rubber
Abstrak: Indonesia merupakan Negara dengan areal perkebunan yang luas. Salah satu komoditas perkebunan yang melimpah di Indonesia adalah karet dan kelapa sawit. Karet terbagi menjadi 2 jenis yakni karet alam dan karet sintetik. Keduanya memiliki sifat kepegasan pantul yang baik. Namun, dalam pemenuhan sifat mekanik baik karet alam maupun sintetik diperlukan adanya bahan pengisi (filler), salah satunya adalah serat Tandan Kosong Kelapa Sawit (TKKS). Penelitian ini bertujuan untuk menganalisa pengaruh konsentrasi filler serat woven TKKS dalam bentuk biokomposit tersusun laminar terhadap kekuatan mekanik karet (alam dan sintetis). Pembuatan biokomposit dilakukan dengan metode hot press. Uji mekanik matrik karet yakni tensile strength, elongation at break, dan rebound resilience menjukan sifat mekanik matrik terbaik adalah karet butyl. Uji impak biokomposit menunjukan sampel terbaik adalah sampel CNR-70, yakni biokomposit bermatriks karet alam dengan hardness 70 dan konsentrasi filler serat TKKS sebanyak 28 lembar., Indonesia is a country with a large plantation area. One of the abundant plantation commodities in Indonesia is rubber and oil palm. Rubber is divided into 2 types, namely natural rubber and synthetic rubber. Both of them have good reflective properties. However, in fulfilling the mechanical properties of both natural and synthetic rubber, a filler is needed, one of which is the fiber of the Empty Oil Bunches (EFB). This study aims to analyze the effect of the concentration of the OPEFB woven fiber filler in the form of a laminar composed biocomposite on the mechanical strength of rubber (natural and synthetic). The biocomposite was made by hot press method. Rubber matrix mechanical tests, namely tensile strength, elongation at break, and rebound resilience showed that the best matrix mechanical properties were butyl rubber. The biocomposite impact test showed that the best sample was the CNR-70 sample, namely the biocomposite with a natural rubber matrix with a hardness of 70 and a concentration of OPEFB fiber filler as much as 28 sheets.
Keyword: biocomposite, filler, rubber, OPEFB

Judul: A Continuous Vaccination Strategy in the SVIR Epidemic Model
Abstrak: Vaccination is conducted to minimize the spread of a disease. The vaccination is usually done several times within a fixed time interval. In the SVIR model, it is assumed that individuals do not get immediate immunity following a vaccination program. So according to process of vaccination on SVIR model, there are two strategies, i.e. the continuous vaccination strategy (CVS) and the pulse vaccination strategy (PVS). In this study, only the CVS strategy in epidemic model SVIR is considered. Results of the study indicate that dynamics of the CVS system depends on the basic reproductive number. If the basic reproductive number is less than one, then the disease-free fixed point is asymptotically stable. It means that the disease will eventually disappear from the population. Conversely, if the basic reproductive number is greater than one, then the endemic fixed point is asymptotically stable, which means that the disease will remain exist in the population. Simulation result shows that the vaccination would minimize the spread of disease by reducing the basic reproductive number. If the time for the vaccinated recipients to obtain the immunity, as well as a possibility of vaccinated recipients to be infected are neglected, then the disease will be eradicated. This condition is called an over-evaluating effect of vaccination.
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