Computational Scale-Up for Flood Fed/Starve Fed Single Screw Extrusion of Polymers

A novel scaling-up computer system for single screw extrusion of polymers has been developed. This system makes it possible to scale-up extrusion process with both starve feeding and flood feeding. Each of the scale-up criteria can be an objective function to be minimized, represented by single values or functional dependencies over the screw length. The basis of scaling-up is process simulation made with the use of the GSEM program (Global Screw Extrusion Model). Scaling-up is performed using the GASES program (Genetic Algorithms Screw Extrusion Scaling) based on Genetic Algorithms. Scaling-up the extrusion process has been performed to increase extrusion output according to the scaling-up criteria defined by the single parameters of unit energy consumption, polymer plasticating rate and polymer temperature, as well as by the process parameters profiles of the temperature and plasticating. The global objective function reached the lowest value for the selected process parameters, and extrusion throughput was significantly increased.

Conversion of Industrial Food Wastes Cranberry Pomace into Foods Blending with Rice Flour Using Single-screw Extrusion Process

The main objective of this study was to convert the cranberry pomace into value-added extruded cereals/snacks blending with rice flour using a single screw extruder based on the physicochemical properties of extrudates because utilization of the byproduct cranberry pomace would be necessary for the growth of cranberry juice processing industries and the extruded snacks/cereals with higher fiber and antioxidant and less carbohydrate would be required to fulfill the consumers’ demand. The six different formulations by blending 0, 5, 10, 15, 20 and 25% cranberry pomace with 100, 95, 90, 85, 80 and 75% of rice flour, respectively, were extruded using a single screw extruder. The temperature (150℃), screw speed (270 rpm), feed rate (20 Kg/hr) and feed moisture content (35%) were constant during extrusion. The physicochemical properties of the extrudates were characterized to determine the desirable formulations. The results indicated that radial expansion ratio (1.11-1.67), the solid density (0.71-0.76 g/mL), piece density (0.20-0.63 g/mL), porosity (14.49-72.38%), hardness (23-157.73 N), crispness (4.17-13.5), moisture content (3.22-4.39%), water activity (0.14-0.36) and the water solubility (7.07-30.80%) of rice flour and cranberry pomace blend extrudates were varied depending on the combinations of the rice flour and cranberry pomace. The results revealed that up to 20% cranberry pomace could be added with 75-80% rice flour to develop high fiber and antioxidant with less carbohydrate cereal/snack products. The utilization of cranberry pomace combining with rice flour through extrusion process can provide a unique opportunity to generate healthier snacks and cereals that have higher fiber and antioxidant and low carbohydrate.

Fifth metatarsal fractures: an update on management, complications, and outcomes

Even though fifth metatarsal fractures represent one of the most common injuries of the lower limb, there is no consensus regarding their classification and treatment, while the term ‘Jones’ fracture has been used inconsistently in the literature. In the vast majority of patients, Zone 1 fractures are treated non-operatively with good outcomes. Treatment of Zone 2 and 3 fractures remains controversial and should be individualized according to the patient’s needs and the ‘personality’ of the fracture. If treated operatively, anatomic reduction and intramedullary fixation with a single screw, with or without biologic augmentation, remains the ‘gold standard’ of management; recent reports however report good outcomes with open reduction and internal fixation with specifically designed plating systems. Common surgical complications include hardware failure or irritation of the soft tissues, refracture, non-union, sural nerve injury, and chronic pain. Patients should be informed of the different treatment options and be part of the decision process, especially where time for recovery and returning to previous activities is of essence, such as in the case of high-performance, elite athletes.

Analisis Perbaikan Stern Tube Poros Propeller Single Screw pada Kapal General Cargo 4192 GT

<p>Dalam proses perencanaan kapal, pada tahap pemasangan poros propulsi di kapal, tentu saja diperlukan penyelarasan yang benar. Kesalahan dapat menyebabkan distribusi beban yang tidak merata pada bantalan, akibatnya menyebabkan abrasi yang tidak normal, kondisi kelebihan beban, kelebihan beban dan kerusakan pada bagian bantalan tertentu, hal tersebut berlaku juga kepada struktur yang mendapat beban statis sebagai tumpuannya. perlunya uji numerik untuk proses analisa terjadinya beban berlebih dalam persiapan reparasi bantalan poros <em>propeller</em> sehingga menunjukan karakter hidrodinamik dan beban yang terjadi ketika bantalan dan poros <em>propeller</em> mulai kontak. Tujuan penelitian ini,menganalisis desain bantalan poros <em>propeller </em>untuk direparasi dan untuk mendapatkan performa terbaik dari sistem kontak antara bantalan dengan poros <em>propeller</em> sehingga merepresentasikan perbandingan kinerja dari <em>propeller</em> sebelum dan sesudah perbaikan. Metode perhitungan dengan metode <em>finite elemen</em> berbasis persamaan matematik merepresentasikan tegangan yang terjadi sesuai karakter material <em>bronze</em> ( AlBr dan CuSn) yang diaplikasikan pada performa bantalan proros <em>propeller</em> kapal tipe <em>general cargo</em> seberat 4192 GT. Hasil analisa menunjukan saat putaran <em>propeller</em> pada rpm mesin yang optimum, tegangan maksimum juga terjadi sesuai dengan hasil percobaan temperatur yang terjadi juga semakin tinggi. Pada beban rpm 525 maka <em>shear stress</em> untuk <em>stern tube</em> material AlBr bernilai 978 Mpa dan pada material SnCu bernilai 948 Mpa. Nilai <em>deflect </em>atau <em>cleareance </em>pada setiap posisi setelah dilakukan perbaikan mengalami peningkatan rata-rata sebesar 24,4 % dari pengukuran awal sebelum dilakukan reparasi. Proses reparasi menunjukan performa yang cukup baik, rata-rata temperatur kerja yang dihasilkan ketika dilakukan pengujian <em>sea trial</em> menurun dari sebelumnya sebesar 7,5%.</p>

A Parametric Study on the HDPE/PP and Marble Slurry Waste Utilisation Using Single Screw Extruder

Due to the increased socio-economic development, the manufacturing of different products based on various polymers for different applications such as space crafts, airplanes, automobiles, boats, and sports equipment are increasing continuously. This huge increase in solid polymer commodities is also creating the extravagant quantity of solid waste polymers (SWPs) due to their non-degradable characteristics. These SWPs, for example, high-density polyethylene (HDPE), polypropylene (PP), low-density polyethylene (LDPE), and nylon, etc., are used frequently in various applications and create new challenges to the industries, government, as well as end-users for systematic waste recycling/recovery in an eco-friendly manner. Moreover, in this modernisation era, almost all marble industries are also facing a huge problem as marble slurry (MS) yields a great burden not only due to its limited degradability characteristics but also wider environmental hazard towards water bodies, and rivers. Fine particles in the range size of 45-300 micron in the MS create air pollution which in turn increases breathing problems. Moreover, it also creates an ecological adverse impact on soil fertility and reduces the percolation rate of rain water which in turn reduces the recharging of groundwater. Therefore, keeping in view the above facts, the simultaneous recycling of HDPE, PP and marble slurry is adopted through single screw extrusion in order to reduce the burden on the environment. Moreover, the effect of various process parameters viz barrel temperature, screw speed (rpm), feed composition, and grain size of PP and HDPE on extrudate output was envisaged. It was found that the extrudate output increases steeply on increasing the average barrel temperature from 100 to 120°C and linearly with screw speed range from 65 to 85 rpm. The effect of grain size had shown decreasing trend in throughput whereas on increasing the polymer content in the feed, throughput was found to be enhanced. Additives such as HPMC were found to be effective when used in synergy with HDPE and PP along with MS. The extrudate throughput was found to be a maximum of 33.01 g/minute at 120°C, 85 screw rpm, 1.40-grain size underfeed with equal proportionate of HDPE/PP with 2% HPMC and 8% MS. This clearly opens the ways for proper utilization of HDPE, PP and MS waste by extrusion and provides the environmental protection solution by utilizing these polluted materials in the fabrication of value-added products through extrusion.