The research was carried out about the effect of adding rice husk ash to physical and mechanical properties of mortar. Mortar was moulded with three composition comparisons between ordinary portland cement, rice husk ash, and rice stalk fiber. Rice husk ash was burned at temperature of 700 OC for 2 hours, rice stalk fiber was mechanically sliced up to 0.8 mm in size, then mortar molding and maintenance was processed for 28 days. The mortars that had reached the age of 28 days were tested according to the Indonesia National Standard (SNI) including physical properties (water absorption, density), and mechanical properties (compressive strength, modulus of elasticity, modulus of rupture). Characterization of microstructure, morphology and counting all elements on the surface of mortar were processed by using Scanning Electron Microscopy - Energy Dispersive X-ray Spectroscopy (SEM-EDS). The results of research that had been carried out, mortar with the most optimum physical and mechanical properties was mortar B with a composition of 65%: 10%: 25%. The results of the characterization using SEM-EDS showed that the surface of mortar B was better with grain diameter (1.4 ± 0.9) µm and the most dominant element in the mortar was element of Ca and Si which functioned as mortar binder and hardener.

Electricity consumption in Padang Lawas Regency has increased every year, namely 59,962,000 kWh in 2018, and reached 74,060320,5 kWh in 2020. This increase is in line with the population growth rate so that it also has an impact on land availability. Forecasting electricity consumption absolutely must be done because it greatly affects the distribution and availability of electrical energy. There are three problems related to electrical energy resources. First, the availability of electricity will decrease as demand increases. The second is the increase in population which has an impact on improving the quality of life of the community and the availability of electricity. Third, the increase in land conversion is increasingly massive, causing population density and energy needs in the region to increase. For this reason, it is necessary to project the need for electrical energy for the population and land conversion in Padang Lawas Regency in 2021-2050. The objectives of this study can be used as a basis and choice for policy and strategy making in regional development planning by the Padang Lawas Regional Government. This is done so that the problem of electricity availability can be resolved. This research was conducted using the PowerSim Studio 10 application by simulating a dynamic system model involving several variables that influence each other. The results showed that population variables affect land requirements and total energy consumption. Analysis of electricity availability in Padang Lawas Regency until 2050 will experience an increase in electricity consumption accompanied by an increase in population and land conversion. Based on the results of the simulation scenario, the availability of electricity in Padang Lawas Regency can meet the total electricity consumption needs until 2050, either with or without intervention.

During Covid-19 pandemic, the increase in LPG types was 0.6-2.4 million BOE, while in the household sector it was 2.3-6.9 million BOE, so causes LPG import growth ratio to increase by 4.8%/year (BPPT, 2020). Therefore, it is necessary to make efforts to suppress LPG imports by increasing the supply of EBT in the household sector with biogas production. The research aims to look at the biogas production modeling system from the resulting cow dung waste. The research method that studies the literature is based on modeling data based on data obtained using Powersim 10. The results showed that LPG demand in 2020 is 2.4 million BOE that could be fulfilled by a biogas source from 9539238.75 kg ~ 0.9 metric tons cow dung waste. This cow dung waste is able to produce 381569.55 m3/kg of methane gas which is equivalent to 0.59 metric tons LPG, savings Rp 690 M; 103 million liters gasoline, savings Rp 793 M; 64.8 million liters diesel fuel, savings Rp 333.8 M; 80 million liters kerosene, savings Rp 1 T; 4.53 metric tons wood, savings Rp 4.5 T. This favorable situation must be immediately felt by the community with an estimate of future benefits.

Electronic transactions or buying and selling online are very popular among students. Until now there are no rules regarding age limits in electronic transactions or buying and selling online so that students or teenagers can make electronic transactions. This study aims to find out and analyze the regulation of online buying and selling transactions carried out by students or teenagers so that they can determine the legal consequences of online buying and selling transactions carried out by students or teenagers. The results showed that most of the MAN students in the Yogyakarta area had made buying and selling transactions through online shops. Even though the ITE Law doesn’t set an age limit for online buying and selling transactions, online buying and selling transactions are still subject to the Civil Code. Online buying and selling transactions carried out by students or teenagers have violated subjective requirements, giving rise to the legal consequences of electronic contracts. The need for special rules regarding age limits in electronic transactions and settlement mechanisms if one of the parties is a student or teenager who is not old enough. Keywords : transactions, buying and selling online, teenagers.

Penyebaran Coronavirus Disease 2019 sangat memberikan dampak yang meluas di beberapa Negara salah satunya di Indonesia. Dampak ditetapkan sebagai pandemi oleh Organisasi Kesehatan Dunia (WHO) pada tanggal 11 Maret 2020, tidak hanya berdampak pada kesehatan tetapi berpengaruh secara ekonomi yang berakibat kegiatan ekonomi menjadi terhambat salah satunya usaha dibidang non perbankkan yakni Leasing. Adapun masalah bagaimana dampak Covid-19 terhadap Perjanjian Kredit antara masyarakat dan Perusahaan Leasing. Dengan demikian terkait dengan kegiatan pengabdian kepada masyarakat, yang merupakan salah satu tugas Tri Dharma Pergurun Tinggi, maka dilaksanakan penyuluhan. Dengan tujuan memberikan ilmu pengetahuan kepada masyarakat tentang dampak covid-19 terhadap perjanjian kredit oleh perusahaan Leasing di masa pandemi covid 19. Metode pelaksanaan penyuluhan yaitu narasumber dalam hal ini Dosen menyampaikan materi penyuluhannya dan dilakukan sesi tanyajawab. Kegiatan penyuluhan dilaksanakan di Desa Mekarmaju dengan sasaran sebagai peserta yaitu masyarakat dan dihadiri sejumlah 21 orang. Desa Mekarmaju ini merupakan Desa Binaan Lembaga Pengabdian kepada Masyarakat Universitas Islam Jakarta. Hasil kegiatan pengabdian kepada masyarakat dapat dilihat dengan antusias masyarakat untuk mengikuti kegiatan pengabdian ini sampai selesai.