Pembuatan Sambungan Part Seat Tube pada Sepeda Menggunakan 3D Printer Berdasarkan Topology Optimization Design

Tahapan pada penelitian ini terdiri dari pemodelan awal sambungan part pada sepeda, simulasi tahap awal dengan menggunakan ANSYS 18 yang meliputi pengaturan boundary condition, meshing dan analisis hasil. Kemudian dilanjutkan dengan simulasi Topology Optimization Design dengan mass retain 60%, 70% dan 80% dimana hasil dari simulasi tersebut akan dilakukan proses smoothing. Setelah itu dilanjutkan dengan simulasi tahap akhir dimana hasil smoothing tersebut diuji kembali dengan metode yang sama dengan simulasi tahap awal, dan kemudian hasil analisis ini akan digunakan untuk menentukan desain terbaik. Tahap terakhir dari penelitian ini adalah dengan membuat model dari desain terbaik mengggunakan 3D Printer, lalu dengan menguji coba sepeda yang telah disambung menggunakan part ini secara langsung. Pengguna sepeda di Indonesia belakangan ini menunjukkan pertumbuhan yang pesat. Sejak diciptakannya sepeda pada abad ke 18 hingga saat ini, sepeda terus berkembang pada bentuk dan penggunaanya. Melihat dari sudut pandang konsumen sepeda, banyak yang lebih tertarik akan model sepeda yang berbeda dari model pada umumnya. Pada saat ini penyambungan antar komponen frame masih dilakukan dengan proses pengelasan namun pengelasan saat ini memiliki keterbatasan dalam penyambungan antar material seperti penyambungan antara aluminium dengan karbon atau untuk material lainnya. Untuk mempermudah proses penyambungan antar dua material yang berbeda dan tidak dimungkinkan dilakukan pengelasan maka proses penyambungan dapat dilakukan dengan cara mengganti sambungan las dengan komponen penyambung yang dibuat dengan menggunakan 3D Printer. Dari simulasi ini, desain terbaik terdapat dari hasil pengujian Pedalling pada mass retain 60% dimana tegangan maksimum yang terjadi pada part ini sebesar 9,58E-04 MPa untuk pengujian Pedalling Forces, 3,13E-5 MPa untuk pengujian Horizontal Forces dan 2,1724 MPa untuk pengujian Vertical Loads. Desain tersebut berhasil dibuat dan diuji meskipun masih ada beberapa evaluasi. Kata Kunci : Topology optimization design, Prototyping dengan 3d Printer, CEN 14766, Frame Sepeda. ================================================================================================ Bicycle users in Indonesia have recently shown rapid growth. Since the creation of bicycles in the 18th century to the present day, the bike continues to grow in shape and usage. Looking from the consumer's point of view of the bike, many are more interested in the different bike models of the model in general. At this time the interconnection between the frame components is still done by the welding process but the current welding has limitations in the interconnection of materials such as grafting between aluminum with carbon or for other materials. To facilitate the process of connecting between two different materials and not possible welding then the connection process can be done by replacing the welding connection with the connecting components made using 3D Printer. The stages of this study consisted of the initial modeling of the connection of parts on the bicycle, the initial simulation using ANSYS 18 which included setting boundary conditions, meshing and yield analysis. Then followed by Topology Optimization Design simulation with 60%, 70% and 80% retain mass where the result of the simulation will be smoothing process. After that it is followed by a final stage simulation where the smoothing results are re-tested with the same method as the initial stage simulation, and then the results of this analysis will be used to determine the best design. The last stage of this research is to create models from the best design using 3D Printer, then by testing the bike that has been connected using this part directly. From this simulation, the best design is from Pedaling result in 60% retain mass where the maximum voltage that occurs in this part is 9,58E-04 MPa for Pedaling Forces test, 3,13E-5 MPa for Horizontal Forces test and 2,1724 MPa for testing Vertical Loads. The design was successfully created and tested although there are still some evaluations. Key Word : Topology optimization design, Prototyping dengan 3d Printer, CEN 14766, Bike Frame

Annular pancreas: endoscopic and pancreatographic findings from a tertiary referral ERCP center

Background and Aims Annular pancreas is a congenital anomaly whereby pancreatic tissue encircles the duodenum. Current knowledge of endoscopic findings of annular pancreas is limited to small case series. The aim of this study was to describe the endoscopic and pancreatographic findings of patients with annular pancreas at a large tertiary care ERCP center. Methods This is a retrospective observational study. Our Institutional Review Board–approved, prospectively collected ERCP database was queried for cases of annular pancreas. The electronic medical records were searched for patient and procedure-related data. Results From January 1, 1994, to December 31, 2016, 46 patients with annular pancreas underwent ERCP at our institution. Index ERCP was technically successful in 42 patients (91.3%), and technical success was achieved in all 46 patients (100%) after 2 attempts, when required. A duodenal narrowing or ring was found in most patients (n = 39, 84.8%), yet only 2 (4.3%) had retained gastric contents. Pancreas divisum was found in 21 patients (45.7%), 18 of which were complete divisum. Pancreatobiliary neoplasia was the indication for ERCP in 7 patients (15.2%). Pancreatographic findings consistent with chronic pancreatitis were noted in 15 patients (32.6%) at the index ERCP. Conclusion This is the largest series describing the endoscopic and pancreatographic findings of patients with annular pancreas. We found that 45.7% of patients had concurrent pancreas divisum. Endoscopic therapy was successful in most patients at our institution after 1 ERCP, and in all patients after a second ERCP. Nearly one-third of patients had findings consistent with chronic pancreatitis at the time of index ERCP. It is unclear whether this may be a feature of the natural history of annular pancreas

Bounds in simple hexagonal lattice and classification of 11-stick knots

The stick number and the edge length of a knot type in the simple hexagonal lattice (sh-lattice) are the minimal numbers of sticks and edges required, respectively, to construct a knot of the given type in sh-lattice. By introducing a linear transformation between lattices, we prove that for any given knot both values in the sh-lattice are strictly less than the values in the cubic lattice. Moreover, we find lower bounds for any given knot's stick number and edge length in sh-lattice using these properties in the cubic lattice. Finally, we show that the only non-trivial 11-stick knots in the sh-lattice are the trefoil knot ($3_1$) and the figure-eight knot ($4_1$).Comment: 25 pages, 17 figure

Overutilization of magnetic resonance imaging in the diagnosis and treatment of moderate to severe osteoarthritis

Advanced imaging is a major driver of health care expenditures. Magnetic resonance imaging provides advantages over radiography because of its ability to visualize soft tissues within the knee joint. The clinical relevance of these findings in osteoarthritis, however, is not well understood. For example, MRI can detect meniscal tears, but these are frequent findings in patients with osteoarthritis, with no difference in prevalence among those with and without symptoms. In addition to concerns about excessive cost, it is possible that patients may undergo unnecessary procedures due to MRI findings. A randomized placebo-controlled trial showed no benefit of arthroscopy for osteoarthritis. Our goal was to examine how prevalent this practice is at this institution, and to examine the characteristics of physicians who ordered these MRIs. Our hypothesis is that many providers order MRI for evaluation of osteoarthritis before referring to an orthopedic surgeon, and that providers with higher levels of training are less likely to order these unnecessary MRIs

Multipartite entanglement in the 1-D spin-12\frac{1}{2} Heisenberg Antiferromagnet

Multipartite entanglement refers to the simultaneous entanglement between multiple subsystems of a many-body quantum system. While multipartite entanglement can be difficult to quantify analytically, it is known that it can be witnessed through the Quantum Fisher information (QFI), a quantity that can also be related to dynamical Kubo response functions. In this work, we first show that the finite temperature QFI can generally be expressed in terms of a static structure factor of the system, plus a correction that vanishes as $T\rightarrow 0$. We argue that this implies that the static structure factor witnesses multipartite entanglement near quantum critical points at temperatures below a characteristic energy scale that is determined by universal properties, up to a non-universal amplitude. Therefore, in systems with a known static structure factor, we can deduce finite temperature scaling of multipartite entanglement and low temperature entanglement depth without knowledge of the full dynamical response function of the system. This is particularly useful to study 1D quantum critical systems in which sub-power-law divergences can dominate entanglement growth, where the conventional scaling theory of the QFI breaks down. The 1D spin-$\frac{1}{2}$ antiferromagnetic Heisenberg model is an important example of such a system, and we show that multipartite entanglement in the Heisenberg chain diverges non-trivially as $\sim \log(1/T)^{3/2}$. We verify these predictions with calculations of the QFI using conformal field theory and matrix product state simulations. Finally we discuss the implications of our results for experiments to probe entanglement in quantum materials, comparing to neutron scattering data in KCuF$_3$, a material well-described by the Heisenberg chain.Comment: 8 pages and 3 figures; 1 page and 1 figure of the appendix; typos corrected; references adde

The Embryonic Transcriptome Of The Red-Eared Slider Turtle (Trachemys Scripta)

The bony shell of the turtle is an evolutionary novelty not found in any other group of animals, however, research into its formation has suggested that it has evolved through modification of conserved developmental mechanisms. Although these mechanisms have been extensively characterized in model organisms, the tools for characterizing them in non-model organisms such as turtles have been limited by a lack of genomic resources. We have used a next generation sequencing approach to generate and assemble a transcriptome from stage 14 and 17 Trachemys scripta embryos, stages during which important events in shell development are known to take place. The transcriptome consists of 231,876 sequences with an N-50 of 1,166 bp. GO terms and EC codes were assigned to the 61,643 unique predicted proteins identified in the transcriptome sequences. All major GO categories and metabolic pathways are represented in the transcriptome. Transcriptome sequences were used to amplify several cDNA fragments designed for use as RNA in situ probes. One of these, BMP5, was hybridized to a T. scripta embryo and exhibits both conserved and novel expression patterns. The transcriptome sequences should be of broad use for understanding the evolution and development of the turtle shell and for annotating any future T. scripta genome sequences