Studi Eksperimental Variasi Pretension Sambungan Baut Baja Tipe Slip Critical

On the bridge connection type found using high strength bolts with the type of slip-critical connections. In the installation of high quality bolt connection types is conducted pretension with using torque wrench or using manual tool by turn of nut. This study aims to determine tensile strength and failure behavior of the critical slip-type connection by varying the value of pretension on single bolt locking connection with different methods. Pretension variation used 90 Tb, 100 Tb and 110 Tb for torque wrench and 2/3, 3/6 and 4/6 rounds for manual tools of pretension respectively.Tensile test performed on each variation and variation locking method. The results showed the tensile strength values at the both locking methods are same and the failure behavior result are the bolt fail in shear and plate changes into an oval shape

Proses Densifikasi Produk Karbonisasi Tandan Kosong Sawit Menjadi Briket Menggunakan Crude Gliserol Produk Samping Biodiesel Sebagai Filler

Empty fruit bunches (EFB) has not been utilized optimally. EFB can be used as source of solid fuel in the form of briquettes. The calorific value of the EFB is 18.200,975 kJ / kg. The calorific value can be increased by carbonization process that is followed by densification process. Carbonization process aims to minimize the elements forming of the smoke, so the exhaust gas can be cleaner. Densification Process aims to increase the density and simplify the handling process. The calorific value of the combustion products can be enhanced by adding the filler. Crude glycerol is used as the filler, because it has a the calorific value of 25.175,98 kJ / kg which aims to improve the calorific value. The purpose of this research is to utilize EFB and wasting crude glycerol as a source of solid fuel, to learn how is the effect of crude glycerol, particle size, and compression pressure, to determine the influence of calorific value and compressive strength of the briquettes produced. EFB Densification uses a hydraulic press in operating conditions of particle sizes (60, 80, and 100 mesh), the composition of the filler (60:40, 70:30 and 80:20) and a pressing pressure (100.110, and 120 bar). Responses were analyzed, namely the calorific value and compressive strength by using Response Surface Methodology. The Best calorific value is obtained by 28.999,4 kJ / kg at 80 mesh particle size, composition filler 53: 47, and the pressing pressure of 110 bar. While the best compressive strength value is 9,5316 kg / cm2 at 100 mesh particle size, composition filler 60: 40, and the pressing pressure of 120 bar. Process conditions is very influence significantly on the calorific value and compressive strength is the composition of the filler and the pressing pressure

Optimasi Proses Karbonisasi Tandan Kosong Sawit Menggunakan Response Surface Methodology

Empty fruit bunches (EFB) is a source of biomass which has not been utilized optimally yet. EFB can be used as source of solid fuel in the form of charcoal because of its high calorific value 18,200.75 kJ / kg. The calorific value can be increased by carbonization. Carbonization is a process to convert lignoselulose biomass into charcoal within temperature range 300 – 600 °C in a limited oxygen environment. The purpose of this research is to utilize EFB as a source of solid fuel, to study the effect of process condition such as temperature, holding time, and feed size towards the characteristics of resulted charcoal and to optimize carbonization process from the data obtained. Reactor used for EFB carbonization is a tube furnace at operating conditions of temperature (350, 400 and 450 °C), holding time (90, 120 and 150 minutes) and feed size (2, 4 and 6 cm). Responses were analyzed, namely the calorific value and volatile matter by using Response Surface Methodology (RSM). Optimum conditions obtained are temperature 450 °C, holding time 90 minutes and feed size 6 cm with calorific value 28,106 kJ/kg and volatile matter 13.47 %. The most influential process variable for calorific value is temperature. Meanwhile for volatile matter, every process variables give significant effect

Karakterisasi Material Kemasan Pulp Cetak tanpa Perekat dari Pulp Batang Jagung

Molded pulp is an alternative packaging which has renewable and biodegradable properties. The use of molded pulp as packaging material still constrained due to the specific data that describes the characteristics of molded pulp has not widely publicized yet. This study was conducted to identify the characteristics of molded pulp as an alternative packaging material. Cornstalk was selected as raw materials which has abundant availabilty. Molded pulp packaging was manufactured by thermoformed methods. The thermoset nature of lignin in cornstalks would give possibilties in manufacture of molded pulp without using adhesive. The results showed the mechanical characteristics of binderless molded pulp from cornstalk pulp which have tensile index from 17.78 to 35.78 Nm/g, tear index from 9,25 to 26,09 mN.m2/g, and burst index from 0.901 to 1.5 kPa.m2/g. The effects of dependent variables on the mechanical properties of molded pulp were studied by statistical modelling using a polynomial second order. The empirical models were deduced to satisfactorily fit experimental data with the values of independent variables and allow to quantifiying the effects of each variables. The most influential factor on tensile and burst index of molded pulp was temperature of processing. Whereas, the processing pressure has greater influence on tear index of molded pulp

Perilaku Kekuatan Baja Tulangan Beton Akibat Kebakaran

In general, when a reinforced concrete suffered a fire, a lot of people tend to replace it with anew reinforced concrete, because they assume that the strength of the element structure isalready changing. Though it is possible to keep re-creating the building by recountingstrength structural elements. The purpose of this studywass to know a changing of yield andtensile strength toward concrete-steel reinforced bar after burning at various temperature.Steel reinforced bar used was 13 mm (S13) and 16 mm (S16) in diameter which is the gradewas (BjTS 40) and (BjTS 35), respectively. The yield and tensile strength as receivedcondition of S13 were 432,02 MPa and 583,62 MPa, respectively, and S16 were 369,38 MPaand 514,58 MPa, respectively. The average yield strength of S13 after burning at 600 °C,800 °C, and 1000°C, were 411,78 MPa, 417,80 MPa, and 428,14 MPa, respectively. And thetensile strength of S13 were 563,64 MPa, 568,83 MPa, and 577,83 MPa, respectively. Theaverage of yield strength of S16 were 346,15 MPa, 358,13 MPa, and 362,28 MPa,respectively. And the tensile strength of S16 were 504,94 MPa, 507,05 MPa, and 518,49MPa, respectively. Based on this result, S13 and S16 concrete-steel reinforced bar beforeand after burning were still in the same grade compare to as rechieved. It can be concludedthat the building after fire at a temperature 600 ° C, 800 ° C and 1000 ° C for 1 hour with 2.5cm concrete cover thickness still meet the strength requirements of the building

Pengaruh Cetakan Sillicone Rubber dan Temperatur Tuang Lilin terhadap Kualitas Pola Lilin pada Investment Casting

Investment casting method is widely used in the industry, it could produce complex and high precision products.One of the important stage in the investment is the wax pattern production, because the quality of the castproduct depends on the quality of the wax pattern. Sillicone rubber in alternative mold material has goodformability, low thermal conductivity, as well as the low cost of raw materials and the processes compared withmetal. Mold sillicone rubber and pour wax temperature varied 55 ºC, 65 ºC and 75 ºC to investigate the effectof these variables on shrinkage of linear wax patterns and volume wax pattern which expressed as percentage.The lowest average of linear shrinkage is 0.65%, which obtained at temperature 55 ºC. The lowest percentage ofvolumetric shrinkage is 7.59 %, which obtained at temperature 55 ºC

Pembuatan Pulp Cetak tanpa Perekat dari Pulp Batang Jagung

Packaging material's demand continue to increase along with the development of industry all over the world. Styrofoam as conventional packaging materials, have been looked for a subtitute because it does not decompose and the depletion of fossil fuels as it's feedstock. Cornstalk has abundant amount as biomass waste. Despite it's well known quality as raw material for pulp, it hasn't got utilized yet. Molded pulp as one of the alternative packaging, has a promising future with it's degradable characteristics and good mechanical properties. Cornstalk as raw material for the pulp along with the empty fruit bunch (EFB) ash works as the alkaline source for the alkaline pulping. The binderless molded pulp then formed with the help of hot press. The thermoset properties of the lignin itself, give the posibility to produce molded pulp without any binder resin. Tensile index, tear index and burst index were determined experimentally to express the mechanical properties of the binderless molded pulp products. This experiment were done as an effort to utilize the biorenewable resource to make a packaging product that could be an alternative to the conventional one.The result indicate that cornstalk as raw material to produce molded pulp gives good mechanical properties compare to styrofoam packaging product. Molded pulp from cornstalk gives tensile index 17,5 – 34 Nm/g, tear index 10 – 26 mN.m2/g and burst index 0,89 – 1,52 kPa.m2/g. In generally, variation of temperature give dominant significant influence to mechanical properties of molded pulp

Karbonasi Pelepah Sawit

Palm fronds only used as a source of raw materials for animal feed, compost and organic fertilizer in the garden area so far. The heating value of palm fronds is 17.200 kJ/kg. The heating value can be improved by conducting carbonization process. Carbonization is a method to process biomass into solid fuel without oxygen where the temperature range is between 400-600 °C. The aim of this study is to produce a solid fuel from palm fronds by using carbonization process, to know the characteristics of products and to see the influence of reaction temperature, carbonization time and particle size of product towards heating value and volatile matter content. Carbonization temperature used were 400, 500, 600oC, carbonization time used were 90, 120, 150 minutes, and particle size used were 2, 4, 6 cm. Processing data in this study was conducted by Response Surface Methodology (RSM) by using Design Expert 7.0.0 program which is experimental design determined by Central Composite Design (CCD). The highest result of heating value was 28.469 kJ/kg at 400oC for 150 minutes and particle size 2 cm. The highest result of volatile matter content was 21,14 %-wt at 670oC for 120 minutes and particle size 4 cm. Significant process condition affecting the heating value was temperature and carbonization time. However, the condition affecting the volatile matter content were carbonization temperature, carbonization time and particle size