Pemodelan, Pengujian, Dan Analisis Getaran Torsional Dari Perangkat Uji Sistem Poros-Rotor

Vibrations of rotating machinary can be classified as translational and rotational. The vibrations occurred in rotational direction are commonly classified as torsional vibration. Torsional vibration can cause fatigue damage of shaft, coupling, or gear. In this paper, a method for measuring torsional vibration is proposed. This method uses two incremental encoders and an algorithm to process the data. To show its effectiveness, the method was implemented to measure torsional vibration of a rotor shaft system. The paper also shows the torsional vibration characteristics of of the system. To predict the torsional natural frequencies of the system, a finite elemen model was developed using Ansys Workbench 11 and the results was validite using a torsional FRF test. The measurement was performed a range of rotational speed to enable a spectral map can be constructed. There were two types of flexible couplings used in this work, a hose coupling and a rubber jaw coupling. The results of the experiment show that the proposed method can be implemented very well to measure the torsional vibration of the rotor shaft-system. In addition, the torsional vibration of the rotor shaft system has a similar characteristics to that of translational vibration, in which vibration signal is dominated by component with frequency of 1xRPM. The results also show that the level of torsional vibration depends on the type of flexible coupling being used. Due to low torsional stiffness, hose coupling produce low natural frequencies than those of jaw coupling. As a consequence, hose coupling are liable to higher vibration than jaw coupling

A blowout jet associated with one obvious extreme-ultraviolet wave and one complicated coronal mass ejection event

In this paper, we present a detailed analysis of a coronal blowout jet eruption which was associated with an obvious extreme-ultraviolet (EUV) wave and one complicated coronal mass ejection (CME) event based on the multi-wavelength and multi-view-angle observations from {\sl Solar Dynamics Observatory} and {\sl Solar Terrestrial Relations Observatory}. It is found that the triggering of the blowout jet was due to the emergence and cancellation of magnetic fluxes on the photosphere. During the rising stage of the jet, the EUV wave appeared just ahead of the jet top, lasting about 4 minutes and at a speed of 458 - \speed{762}. In addition, obvious dark material is observed along the EUV jet body, which confirms the observation of a mini-filament eruption at the jet base in the chromosphere. Interestingly, two distinct but overlapped CME structures can be observed in corona together with the eruption of the blowout jet. One is in narrow jet-shape, while the other one is in bubble-shape. The jet-shaped component was unambiguously related with the outwardly running jet itself, while the bubble-like one might either be produced due to the reconstruction of the high coronal fields or by the internal reconnection during the mini-filament ejection according to the double-CME blowout jet model firstly proposed by Shen et al. (2012b), suggesting more observational evidence should be supplied to clear the current ambiguity based on large samples of blowout jets in future studies.Comment: APJ, Accepted October 19, 201

A new small satellite sunspot triggering recurrent standard- and blowout-coronal jets

In this paper,we report a detailed analysis of recurrent jets originated from a location with emerging, canceling and converging negative magnetic field at the east edge of NOAA active region AR11166 from 2011 March 09 to 10. The event presented several interesting features. First, a satellite sunspot appeared and collided with a pre-existing opposite polarity magnetic field and caused a recurrent solar jet event. Second, the evolution of the jets showed blowout-like nature and standard characteristics. Third, the satellite sunspot exhibited a motion toward southeast of AR11166 and merged with the emerging flux near the opposite polarity sunspot penumbra, which afterward, due to flux convergence and cancellation episodes, caused recurrent jets. Fourth, three of the blowout jets associated with coronal mass ejections (CMEs), were observed from field of view of the Solar Terrestrial Relations Observatory. Fifth, almost all the blowout jet eruptions were accompanied with flares or with more intense brightening in the jet base region, while almost standard jets did not manifest such obvious feature during eruptions. The most important, the blowout jets were inclined to faster and larger scale than the standard jets. The standard jets instead were inclined to relative longer-lasting. The obvious shearing and twisting motions of the magnetic field may be interpreted as due to the shearing and twisting motions for a blowout jet eruption. From the statistical results, about 30% blowout jets directly developed into CMEs. It suggests that the blowout jets and CMEs should have a tight relationship.Comment: ApJ 18 pages, 7 figure

Simulation of sub-drains performance using visual MODFLOW for slope water seepage Problem

Numerical simulation technique was used for investigating water seepage problem at the Botanic Park Kuala Lumpur. A proposed sub-drains installation in problematic site location was simulated using Modular Three-Dimensional Finite Difference Groundwater Flow (MODFLOW) software. The results of simulation heads during transient condition showed that heads in between 43 m (water seepage occurred at level 2) until 45 m (water seepage occurred at level 4) which heads measurement are referred to mean sea level. However, elevations measurements for level 2 showed the values between 41 to 42 m from mean sea level and elevations for level 4 between 42 to 45 m from mean sea level. These results indicated an increase in heads for level 2 and level 4 between 1 to 2 m when compared to elevations slope at the level 2 and level 4. The head increases surpass the elevation level of the slope area that causing water seepage at level 2 and level 4. In order to overcome this problems, the heads level need to be decrease to 1 until 2 m by using two options of sub-drain dimension size. Sub-drain with the dimension of 0.0750 m (diameter), 0.10 m (length) and using 4.90 m spacing was the best method to use as it was able to decrease the heads to the required levels of 1 to 2 m

Simulation of sub-drains performance using visual MODFLOW for slope water seepage Problem

Numerical simulation technique was used for investigating water seepage problem at the Botanic Park Kuala Lumpur. A proposed sub-drains installation in problematic site location was simulated using Modular Three-Dimensional Finite Difference Groundwater Flow (MODFLOW) software. The results of simulation heads during transient condition showed that heads in between 43 m (water seepage occurred at level 2) until 45 m (water seepage occurred at level 4) which heads measurement are referred to mean sea level. However, elevations measurements for level 2 showed the values between 41 to 42 m from mean sea level and elevations for level 4 between 42 to 45 m from mean sea level. These results indicated an increase in heads for level 2 and level 4 between 1 to 2 m when compared to elevations slope at the level 2 and level 4. The head increases surpass the elevation level of the slope area that causing water seepage at level 2 and level 4. In order to overcome this problems, the heads level need to be decrease to 1 until 2 m by using two options of sub-drain dimension size. Sub-drain with the dimension of 0.0750 m (diameter), 0.10 m (length) and using 4.90 m spacing was the best method to use as it was able to decrease the heads to the required levels of 1 to 2 m

Deformasi Gunung Kelud Pascapembentukan Kubah Lava November 2007

DOI: 10.17014/ijog.v5i1.90The eruption of Kelud Volcano in 2007 was started with an increase in the seismic activity on September 2007. It was ended with a lava dome formation inside the crater lake on 3 November 2007. This phenomenon showed the change of eruption behavior compared to the last eruption on February 1990 that was an explosive one. Result from the GPS observation method during three periods, which are: April, August, and October 2008 showed that the vector displacement on each measured point was affected dominantly by structural geology forces as a crustal stabilisation after the last phase of November 2007 eruption. There was also a minor displacement as the result of magma migration around the points that were close to the lava dome. The magma migration occurred in a relatively shallow depth and was associated with an aseismic zone. The deformation that occurred as a result of magma migration toward the surface was calculated to determine the magma supply and magma injected. The result then was compared to illustrate a mechanism of deformation during April – October 2008. The comparison of magma supply and magma injected within these periods showed that the inflation still occurred, but it was not supported by a surface manifestation. This inflation could be false because of data discontinuity, or it is actually a part of deflation trend

Loss Estimation of Protected Forest Damage and Its Impact on Fishery Sector in Goa Cina Beach, South Area of Malang Regency

Goa Cina is one of magnificent beach destinations in the South Area of Malang Regency which attracts local and foreign tourists. Generally, there are two kinds of tourism management namely ecoturism based and masstourism based. However, Goa Cina implements masstourism based management. Thus it needs an area to build tourism facilities and infrastructures. The ideal functions of protected forest had conversed into buildings such as parking lots, stalls, religious buildings, restrooms, etc. The damage of protected forest caused by its missing functions contributes to some losses. The aims of this research were to: 1) count the loss as the impact of protected forest conversion in Goa Cina which turned into tourism facilities and infrastructures; 2) analyze its impact on fishery production. The data were collected by conducting in-depth interview with the key informant and finding secondary data. The result indicated that the conversion of protected forest into tourism facilities and infrastructures caused ecological and economic loss and it needed massive ecological recovery. The fishery production also decreased due to sedimentation of saltwater. It is suggested that ecotourism should be considered for tourism development instead of masstourisnm

Effect Of Entrepreneurship Characteristics Of Fish Farmer Entrepreneurial Intentions Seedling People On The Unit (Upr) Sumbermina Sustainable In Village Sumbersekar District DAU Malang

Development of entrepreneurship is seen as a strategic step in solving the nation's economic problems (Milla, 2013). According to Krueger, Reilly and Casrud (2000), stated that entrepreneurship is the kind of behavior that was planned very precisely when explained using the theory of intentions. The purpose of this study was to knowing the profile and business activities of fish farmers in the UPR Sumbermina Lestari, knowing the characteristics of entrepreneurship and entrepreneurial intentions of UPR Sumbermina Lestari, and analyze the influence of entrepreneurial characteristics with entrepreneurial intentions both partially and simultaneously. This research is descriptive. The data used is quantitative data and qualitative data. Source data used are primary data and secondary data. The object of research in the form of entrepreneurial characteristics consisting of innovation, need for achievement, internal locus of control, risks taking, tolerance for ambiguity, self confident, and future-oriented as a variable X with the intention of entrepreneurship as a variable Y. research instruments testing using three test was validity and reliability test, and test assumptions multikolinieritas. There are two methods of data analysis in this study, descriptive statistical analysis, and logistic regression analysis

Cognitive Therapy Decrease the Level of Depression

Introduction: Aging is a natural process in individuals. Most of the elderly have problems in dealing with this natural process. Lost of occupation, friends and loneliness may result in depression in this age group. Cognitive therapy changes pessimistic idea, unrealistic hopes and excessive self evaluation may result and justify depression. Cognitive therapy may help elderly to recognize the problem in life, to develop positive objective of life and to create more positive personality. The aimed of this study was to analyze the effect of cognitive therapy to reduce the level of depression. Method: This study was used a pre experimental pre post test design. Sample were 10 elderly people who met to the inclusion criteria. The independent variable was cognitive therapy and dependent variable was the level of depression in elderly. Data were collected by using Geriatric Depression Scale (GDS) 15, then analyzed by using Wilcoxon Signed Rank Test with significance levelα≤0.05. Result: The result showed that cognitive therapy has an effect on reducing depression with significance level p=0.005. Discussion: It can be concluded that cognitive therapy was effective in reducing depression level in elderly. Further studies are recommended to analyze the effect of cognitive therapy on decreasing anxiety in elderly by measuring cathecolamin