Academic literature on the topic 'Jim Tressel'

PT. Perkebunan Nusantara V mengolah kelapa sawit yang menghasilkan Crude Palm Oil (CPO) dengan produksi 60-ton TBS/jam. Proses produksi yang berlangsung di Perusahaan sering mengalami pemberhentian yang diakibatkan oleh tingginya frekuensi kerusakan mesin thresher dikarenakan sistem perawatan yang belum optimal menyebabkan waktu penundaan (Down Time) 2-3 jam untuk proses perbaikan di mesin tersebut. Hal ini dapat dilihat pada data kondisi mesin thresher tahun 2018 yaitu terdapat 18 kali komponen mesin yang harus mengalami perawatan di luar dari perawatan mesin. Permasalahan ini bisa terjadi 4-5 kali dalam 1 bulan berdampak buruk pada perusahaan yaitu menurunkan jumlah rendemen. Maka dari itu pada penelitian ini akan dilakukan penentuan aktifitas perawatan mesin tresher agar kerusakan pada mesin dapat diminimalisir dengan pendekatan Failure Mode Effect Analysis (FMEA) dan Realibility Centered Maintenance (RCM). Dari hasil FMEA terhadap 18 komponen mesin tresher dengan RPN terbesar adalah Gearbox dengan nilai 648 poin. Selanjutnya dari hasil RCM dengan aktifitas perawatan schedule on condition dan schedule on restoration task terdapat 9 komponen. Untuk hasil dari MVSM pada proses penggantian komponen mesin tresher terdapat delay maka dilakukan simulasi arena dan penjadwalan penggantian komponen mesin, maka nilai efisiensi penggantian meningkat untuk komponen Gearbox dari 40% naik menjadi 54,26%. PT. Perkebunan Nusantara V processes oil palm which produces Crude Palm Oil (CPO) with a production of 60 tons of FFB / hour. The production process that takes place at the Company often has a stop caused by the high frequency of damage to the engine thresher because the maintenance system that has not been optimal causes a delay time (Down Time) of 2-3 hours for the repair process on the engine. This can be seen in the data on the condition of the thresher engine in 2018, which is 18 times the engine components that have to be treated outside the engine maintenance. This problem can occur 4-5 times in 1 month which has a negative impact on the company, namely reducing the amount of yield. Therefore, this research will determine the tresher engine maintenance activities so that damage to the engine can be minimized using the Failure Mode Effect Analysis (FMEA) approach and Reliability Centered Maintenance (RCM). From the results of the FMEA on the 18 components of the tresher engine with the largest RPN is Gearbox with a value of 648 points. Furthermore, from the RCM results with maintenance schedule on condition activities and schedule on restoration tasks there are 9 components. For the results of MVSM in the replacement process of tresher engine components there is delay, then an arena simulation and scheduling of engine components are replaced, then the value of replacement efficiency increases for Gearbox components from 40% to 54.26%.

In this paper a detailed analysis of undular bore dynamics in channels of variable cross-section is presented. Two undular bore regimes, low Froude number (LFN) and high Froude number (HFN), are simulated with a Serre–Green–Naghdi model, and the results are compared with the experiments by Treske (1994). We show that contrary to Favre waves and HFN bores, which are controlled by dispersive non-hydrostatic mechanisms, LFN bores correspond to a hydrostatic phenomenon. The dispersive-like properties of the LFN bores is related to wave refraction on the banks in a way similar to that of edge waves in the near shore. A fully hydrostatic asymptotic model for these dispersive-like bores is derived and compared to the observations, confirming our claim.

A two-layer long-wave approximation of the homogeneous Euler equations for a free-surface flow evolving over mild slopes is derived. The upper layer is turbulent and is described by depth-averaged equations for the layer thickness, average fluid velocity and fluid turbulent energy. The lower layer is almost potential and can be described by Serre–Su–Gardner–Green–Naghdi equations (a second-order shallow water approximation with respect to the parameter $H/L$, where $H$ is a characteristic water depth and $L$ is a characteristic wavelength). A simple model for vertical turbulent mixing is proposed governing the interaction between these layers. Stationary supercritical solutions to this model are first constructed, containing, in particular, a local turbulent subcritical zone at the forward slope of the wave. The non-stationary model was then numerically solved and compared with experimental data for the following two problems. The first one is the study of surface waves resulting from the interaction of a uniform free-surface flow with an immobile wall (the water hammer problem with a free surface). These waves are sometimes called ‘Favre waves’ in homage to Henry Favre and his contribution to the study of this phenomenon. When the Froude number is between 1 and approximately 1.3, an undular bore appears. The characteristics of the leading wave in an undular bore are in good agreement with experimental data by Favre (Ondes de Translation dans les Canaux Découverts, 1935, Dunod) and Treske (J. Hydraul Res., vol. 32 (3), 1994, pp. 355–370). When the Froude number is between 1.3 and 1.4, the transition from an undular bore to a breaking (monotone) bore occurs. The shoaling and breaking of a solitary wave propagating in a long channel (300 m) of mild slope (1/60) was then studied. Good agreement with experimental data by Hsiao et al. (Coast. Engng, vol. 55, 2008, pp. 975–988) for the wave profile evolution was found.

Pandan tikar (Pandanus tectorius Park.) fruit has the potential to be processed into various food products nevertheless the information on the right maturity level to be processed is limited. This study aims to determine the performance of pandan tikar fruit based on physical properties, vitamin C and total soluble solids (TSS) content at three levels of maturity. The fruits were collected from tress that grown at Mansinam Island and costal area of Northern Manokwari. Observations were made to changes in fruit performance, including the shape, color, weight and size of the fruit drupa, the content of vitamin C as well as TSS in three maturity levels (semi-ripe, ripe and over-ripe). The results of this study indicate that the fruit shape of pandan tikar was oval and continue to develop in weight, width and length of whole fruit and part of fruit (drupa and pith) during maturity development. The color of semi-ripe phase was light yellow then change to yellow in ripe phase and dark yellow in over-ripe phase. The highest vitamin C content was obtained on pandan tikar fruit from costal area of Northern Manokwari, and the maximum of Vitamin C content found in the mature phase (138.3 mg/100 g), and then decreased in over-ripe phase (49.5 mg/100 g). The TSS were obtained on pandan tikar fruit from Mansinam Island, and will increase from 5.2 to 12.5 °Brix with increasing fruit maturity level. The maximum Vitamin C and TSS of pandan tikar fruit found in the ripe and over-ripe phase; therefore the fruit in the phase is good for producting jam, dodol and syrup.