Sampah plastik adalah salah satu masalah lingkungan yang ada di Indonesia. Sampah plastik meupakan jenis sampah yang sulit terurai, sehingga perlu penanganan khusus untuk pengolahan masalah tersebut. Salah satu alternatif yang ditawarkan yaitu dengan pembuatan mesin pencacah plastik. Salah satu dalam manufaktur suatu mesin yaitu menrancang dan menganalisa komponen yang digunakanan. Mata pisau merupakan salah satu komponen penting pada mesin pencacah plastik. Simulasi model dari mata pisau sendiri perlu dilakukan untuk menganalisa kinerja dari mata pisau tersebut saat proses kinerja mesin tersebut. Permodelan simulasi dilakukan menggunakan software CAE. Bentuk meshing pada permodelan mata pisau yaitu menggunakan tetrahedral dan rasio meshing yaitu mendekati 1. Hasil yang didapatkan dari proses permodelan mata pisau yaitu tegangan maksimum Von mises pada pembebanan 300N, 500N dan 700N berturut turut sebesar 6,752 x 10-3 MPa, 2,845 x 10-3 MPa dan 1,575 x 10-3 MPa. Sedangkan besaran displacement pada variasi pembebanan 300N, 500N dan 700N berturut turut memiliki nilai 6,752 x 10-2 mm, 1,125 x 10-1 mm dan 1,575 x 10-1 mm. Safety factor pada simulasi ini dihasilakan yaitu memiliki nilai 15 yang artinya aman untuk semua variasi pembebanan karena memiliki nilai lebih dari 1.

The high level of rice production in Indonesia creates a large amount of waste material as the husks are removed from the edible portion of the rice grains. Grain milling plants—located in almost every region of Indonesia—cause environmental pollution from the incineration of the unused husks. This study investigated the viability of reducing pollution by making effective use of the husks. Our goal was to determine the suitability of rice husk charcoal as a substitute for sand in the manufacturing of concrete. Testing included the weight of both solid and loose components, absorption, and strength. Rice husk was burned to form the charcoal. Cube-shaped concrete test objects were prepared with a size of 15cm x 15cm (up to 15 pieces) with a predicted compressive strength of 25 MPa. The mix design used Indonesian standard SNI 03-2834-2000. Our overall conclusion was positive. We obtained the following test results for the charcoal: weight of 0.581, density of solid contents 258.21 kg/m³, density of the loose contents 247.37 kg/m³, and absorption of 0.51. The compressive strength test of the concrete at 28 days yielded a strong press of 21.7 MPa; at 56 days this was 27.4 MPa; and at 90 days, 31.8 MPa. The Rat content was 2.150 kg/m³ when tested at 56 days and 90 days. Compressive concrete strength exceeded the projected value of 25 MPa, achieving a range of 27.4–31.8 MPa. The rice husk charcoal could be used as an effective substitute for sand and caused heavy concrete to become lighter.

Along with the advancement of time, technology in the field of building construction, especially concrete manufacturing, is also experiencing very rapid development, almost every aspect of human life is always associated with concrete. The use of added materials has been done in the process of concrete admixture. Based on this, this study aimed to determine the increase in optimal compressive strength of concrete with additional material of husk charcoal and compressive strength of the plan at 28 days is 20 MPa. In this study using the percentage variation of husk charcoal 0 %, 2 %, 4 %, and 6 % by weight of cement. The analytical review of this research is the compressive strength, with concrete cylindrical specimens having a diameter of 15 cm and a height of 30 cm. The concrete mix planning method uses the Indonesian National Standard (SNI) method. The material for this experiment is rice husk which is made into charcoal by manual process. After testing and research, the results show that the use of rice husk charcoal results in reduced workability because the absorption capacity of rice husk is quite high, and the strength of concrete with the addition of husk charcoal by 2 %, 4 %, and 6 % concrete increases its strength from compressive strength concrete plans of 20 MPa. Concrete compressive strength with a mixture of 2% husk charcoal produces compressive strength of 24, 3 MPa, there is an increase of 4, 3 MPa with the addition of husk charcoal by 2 %.

The need for lightweight concrete in a variety of applications of modern construction technology is increasing rapidly, the weight and compressive strength of structural lightweight concrete is 1,850 kg / m 3 , and the compressive strength of 17.2 MPa. Many methods are used to obtain lightweight concrete, including in this study conducting experiments to make structural lightweight concrete using iron wood waste, iron wood is made to replace rough aggregate by cutting iron wood into pieces and then coated with leakproof without dropping paint followed by sprinkling sand while the paint is still wet. From the test results the weight and compressive strength at 28 days, concrete weight 1772 kg / m 3 , and compressive strength 17.99 MPa. From the results of strong and compressive strength tests using iron wood waste as a substitute for coarse aggregate, concrete using iron wood aggregate meets the standards as structural lightweight concrete. That the use of iron wood waste as a substitute for coarse aggregate in the way that we make can be an alternative as a substitute for coarse aggregate for making structural lightweight concrete. This material in addition to being used as material for making structural lightweight concrete can also help reduce waste.

Vocational students need some skills that will be used when students finish their studies at school. One of the expected skills is the ability to draw using the AutoCAD program. Where the final ability is expected of the students will be able to create engineering drawings in the form of 2-D models. The purpose of the training program is to develop and improve the technical drawing skills of the XII class students in using the AutoCAD program. Therefore, the students of class XII SMK have the ability to draw machine components and other engineering drawings in 2-D format. The method used in this training program through pre-test instrument, AutoCAD module, discussion, display through slide how to make machine image in 2-D formats and practice how to make the engineering drawing then evaluated with post-test. The result of this program is the improvement of the ability of grade XII students in drawing machine components and other engineering drawings in 2-D format.