Stinging Nettle (Urtica dioica L., latin) is a wild plant that grows in Indonesia, Asia, and Europe. Nettle in Bali, Indonesia is called as Lateng, Jelatang. Nettle plant has a very strong fiber and high fixed carbon. Nettle plants are covered with fine hairs, especially in the leaves and stems. When it is touched, it will release chemicals, sting and trigger inflammation that causes redness, itching, bumps and irritation to the skin. Nettle plants grow in the wild, regarded as a weed in the agricultural industry, easy to grow and snatch food from the parent plant. The main objective of this paper is to review of the potential nettle fibers and then explain about the potential of local nettle plant in Indonesia. Nettle is a plant group at the end of bast. Its plant fibers taken from the bark, as reinforcement in composite materials. Nettle fibers have three main advantages such as strong, lightweight and low environmental impact.

Plastic waste especially plastic bags have not been widely reused or recycled so that the amount increases polluting the environment every day. One way to overcome this problem is by utilizing plastic waste into paving blocks as a substitute for cement. The problem is how the composition of plastic and sand. The purpose of this study is to determine the effect of using LDPE waste into a mixture of sand with ratios of 1:3, 1:5, and 1:7 with heating temperature of 200°C to the compressive strength and density of sand/LDPE composites. Based on the results of the study, the highest average compressive strength was resulted by the sample which has a ratio of 1:3 plastic and sand with 3mm sand grain and a heating temperature of 200°C which is equal to 32.7MPa. While the lowest average compressive strength was obtained by the sample which has a ratio of 1:7 plastic and sand, 3mm granules and temperature 200°C with a compressive strength of 12.0 (MPa). Increasing the mixture of plastic and sand 1:3, 1:5, 1:7 in which of the followed by increasing of density of the sample.

Stinging nettle is a perennial herbaceous plant belonging to the Urticaceae family, In Bali Indonesia called jelatang. This species is considered a weed in intensive agriculture as its fast vegetative growth and high densities enable increased spread and soil coverage. In Tabanan Bali Indonesia several places to grow are in Denbantas altitude 200-500 meters and in Bedugul altitude 1000 -1500 meters above sea level. Nettle fibers are natural fibers that can be utilized as reinforcement for composite materials. Natural fibers have been used worldwide as a potential replacement for glass fiber reinforced composites, over the last few years has been applied in the automotive sector, aircraft interior and interior of the building. Properties of the natural fiber is lighter, easier to handle, not abrasive, and low cost. The objective of this study was to compare the composition and the tensile strength of the fiber nettle based growing areas from Bedugul and Denbantas. The method used is a fiber tensile test equipment, fourier transformer infrared red (FTIR), thermo-gravimetric analysis (TGA) and scanning electron microscope (SEM). From the research of nettle fibers that stinging nettle from Denbantas has a better tensile strength than Bedugul nettle. The TGA test the visible fiber from Denbantas is superior when used as a composite reinforcement.

Significantly advantage in the use of indentation testing its use for the characterization of materials is simple and requires only a small sample. In material characterization by indentation, the material behaviour is represented by the load (P)- depth (h) in the P-h curve. However, despite the breadth of use of indentation in the evaluation of the behaviour of the material has not been able to explicitly relate the behaviour of materials with constitutive material properties. This encourages further research to be able to predict the P-h curves and hardness and indentation resistance of the constitutive parameters of the material, it is also very important for research and practical use to explore the potential for using indentation data for predicting the constitutive properties of a material. This could potentially provide a faster way for identification of material parameters and applied in situations where a standard specimen is not available. In this research, the relationship between the constitutive parameters of the material (represented by the yield stress (σy) and work hardening coefficient (n)) of elasto-plastic materials, Indentation P-h curve, and Hardness value with dual indenters have been systematically investigated by combining the representative stress (σr) analysis and FE modelling using steel as a system materials. FE model of Vickers and Spherical indentation has been developed and validated. Validation conducted on the feasibility of the FE models to investigate approaches to the material system, and establishing factors affecting the accuracy and robustness of the approach finite element programs used. A new approach for predicting the hardness values are developed based on the 3D relationship between hardness, yield stress (σy) and strain hardening coefficient (n). The prediction proposed method has been successfully used to produce hardness values of various material properties and is used to establish the relationship between the hardness values with representative stress. Prediction process of the material parameters based on the intersection between the indentations curves of the material properties of both the dual indenter Vickers and spherical indentation. It provides a useful tool to evaluate the feasibility of using a hardness value in predicting the constitutive material parameters with respect to the accuracy and uniqueness by mapping through all the range of potential materials