Along with the times, the availability of fossil energy is decreasing, especially natural gas and coal, before using fossil energy, humans have used biomass as an energy source. Indonesia has many plantation commodities, one of which is coffee which is the fourth largest coffee producer in the world. Coffee grounds are the main waste produced by coffee shops and are usually only thrown away. The main ingredients in this study were arabica coffee grounds and robusta. By using robusta composition 60% arabica 40%, robusta 50% arabica 50% robusta 40% arabica 60%. In addition, briquettes are tested for hardness by making points on the surface of the briquettes using a durometer shore A tool of 30 points, then a calorimeter bomb test is carried out to obtain the calorific value content. The result obtained from the highest hardness value is briquettes with a robusta mixture of 50% arabica 50% with a value of 23.7 HA, while the highest calorific value is found in a robusta mixture of 60% arabica 40% with a value of 4526.85 cal / gram.

Briquettes are a type of alternative energy whose raw material source Plastic waste is an environmental problem faced by the people of Indonesia and the world. On the other hand, the production of waste generated in various institutions and sectors in Indonesia continues to increase every year, including the industrial sector whose production process is large-scale. Its use as a basic material for packaging bottles reaches 30% of world use. PET is also used as a synthetic fiber or polyester which accounts for 60% of world use. Study the author will do that is to make a tubing made from PET plastic waste that can be used as raw material for tubing. Using temperature variations (190?, 200?, 210?), then 9 samples from each variation will be micro-photographed the effect of temperature on tubing results and tested for maximum tensile. After that, calculations are carried out to obtain the maximum tensile stress and strain values. Then the average maximum load value that can be received by PET tubing is highest at 190ºC temperature tubing has the ability to withstand tensile strength better than all temperature variations so that the average value is 35.94 N/mm2 and 200ºC is able to withstand 35.49 N/mm2 and 210ºC with 18.30 N/mm2. It can be interpreted that the higher the temperature, the effect on holding the tensile strength of the PET tubing and making the plastic structure change so that 210oC is close to the recycling value, while for temperatures below it is still non-recycled.

Candlenut shell is an organic waste that has a hard texture and has a high carbon element. The amount of candlenut shell produced from each processing of candlenut seeds is very large but has not been optimally utilized. For this reason, an effort is needed to utilize candlenut shells so that they do not become waste. In the manufacture of hazelnut shell briquettes, hazelnut shells are carbonized at 500 °, sifted with mesh 30 and 100 sieves, given a compressive load of 3 kg, 4 kg, 5 kg and 5.5 kg, the adhesive on hazelnut shell briquettes is starch and drying is carried out with a drying oven for 3 hours at a temperature of 80 °. The purpose of this study was to determine the effect of variations in pressure and particle size on the quality of hazelnut shell briquettes when viewed from the combustion rate and calorific value. The methodology used in this research is experimentation on hazelnut shell briquettes, testing hazelnut shell briquettes including testing water content, testing ash content, burning rate and calorific value of briquettes. From the results of the research on hazelnut shell briquettes with variations in pressure and mesh, the highest calorific value in hazelnut shell raw material briquettes is in the 5.5 Kg pressure specimen on mesh 30, namely 9855.18 Cal/gram and the bomb calorimeter test results are 7008.03 Cal/gram with an error rate of 24.40%, the higher the pressure will produce a higher calorific value as well. The highest combustion rate value is in hazelnut shell briquettes at a pressure specimen of 3 Kg mesh 100 with a value of 1.2 grams/minute the smaller the particle size, the higher or faster the combustion rate.

The current fuel is still sourced from fossil fuels, namely oil, coal and The current fuel is still sourced from fossil fuels, namely oil, coal and gas, which have many impacts on the environment. As an agricultural country located in the tropics, Indonesia is rich in biomass energy sources. In this research, the use of candlenut shells will be used or processed into alternative fuel, namely briquettes, with the aim of determining the value of combustion time and temperature produced through variations in composition and mesh size. The results of the research show that the effect of the burning temperature has an impact on the burning time of the briquettes and the resulting temperature, where the best burning time and temperature values ??of the briquettes are produced by a burning temperature of 400°C with a grain size of 100 mesh, namely 177 minutes with an average burning temperature briquettes 193.9°C.

Briquettes are a type of alternative energy whose raw material source comes from agricultural waste such as coconut shells. Coconut shells are converted into charcoal which has a higher calorific value through the pyrolysis process. The aim of this research is to determine the effect of comparing particle size and printing pressure on the length of burning time and burning temperature, so as to obtain a briquette composition that is durable and produces high temperatures. In this research, the raw material used was shell waste with a drying process of 400°C and the particle size variations used were mesh 30, 150 and 250 mixed with 12 grams of starch adhesive. The briquette molding process uses 3 kg and 5 kg pressure, which are then dried using an oven at a temperature of 750°C for 3 hours. Tests were carried out on burning time, burning temperature, water content and ash content. From the research results, it was found that for the highest temperature, briquettes with a particle size of 250 mesh were produced with a pressure of 5 kg at 312°C, and the flame duration of the briquettes was 240 minutes.

One of the reasons the Sugar Factory failed to meet its sugar production target was due to damage to the machine components, particularly at the milling station, where the milling rollers are located. The milling rollers play a crucial role in extracting juice from sugar cane, separating the juice from the bagasse, and measuring the raw juice before it enters the purification process. This unit is designed to maximize raw juice yield while minimizing the amount of bagasse. The milling rollers are arranged in a triangular configuration of three mills, with a milling path between the front and rear rollers that can move forward and backward. Several common issues affect the milling rollers, including surface wear, damage from excessive loads, and wear from repeated friction between the rollers and the sugar cane. Sugar cane itself contributes to roller wear due to its composition, which includes water, sucrose, cellulose, lignin, hemicellulose, ash, and silica. These substances are highly corrosive, even to stainless steel, and act like abrasives against the rollers. The usual remedy at the factory is to weld stainless steel onto cast iron rollers. However, this method has only been moderately effective, as the rollers continue to experience wear after a short period. Based on field observations and literature reviews, some suggested solutions include more frequent cleaning and applying a tungsten coating to the roller surfaces.

The primary function of mobile robots is to transport various loads, including their own weight and additional cargo. Ensuring adequate torque in the wheel motors is crucial for effective load-bearing and movement. This study investigates the load-carrying capabilities of the TT DC gearbox motor, a popular and cost-effective choice for small robots. A mobile robot equipped with four TT DC gearbox motors and employing skid steering locomotion was constructed for this purpose. The robot featured a container designed to carry sand, and its load capacity was tested by gradually increasing the weight until the robot could no longer move. Experimental results showed that the maximum load the robot could carry on a flat surface was 4000 grams, which corresponds to 1000 grams per 5 cm diameter wheel, driven by a stall torque of 0.08336 Nm (0.85 kg.cm). This finding is consistent with the motor's specified stall torque of 0.8 kg.cm at 6V. These results suggest that the maximum load of a mobile robot can be predicted using the motor's stall torque specification and the wheel radius through the total tractive effort (TTE) formula. This study offers valuable insights into estimating the performance limits of DC gearbox motors used in driving mobile robots.