Sistem Pengatur Tegangan Otomatis : Analisa Peralihan Dengan Pengendali Tunggal Dan Kaskade

This journal describes the design and analysis of the response of a single controller and cascade direct current type of Automatic Voltage Regulator (AVR) system. The direct current AVR system is represented form of a transfer function. For single and cascade controllers, it is designed using a parallel architecture using MATLAB software with predetermined design criteria. The types of controllers used consist of Proportional Differential (PD), Proportional Integral (PI), Proportional Integral Differential (PID), Proportional Differential with First Order Filters in the Differential Section (PDF) and Proportional Integral Differentials with First Order Filters in the Differential Section(PIDF). For the transition analysis, the observed parameters consist of rise time, peak time, steady state time, maximum pass value and peak value. The results of the analysis show that the controllers that meet the design criteria are Proportional Differential (PD) controllers and Proportional Differential controllers with First Order Filters in Differential Sections (PDF) for single controllers and cascade controllers. For a single controller, the value of the Proportional constant (Kp) is 0.6280 and the value of the Differential constant (KD) is 0.1710 for the Proportional Differential (PD) controller. Proportional constant value (Kp) is 0.6130, Differential constant value (KD) is 0.1710 and filter constant value (Tf) is 0.0009 for Proportional Differential controller with First Order Filter in Differential Section (PDF). Cascade controllers and Proportional Differential (PD) controllers, the Proportional constant (Kp) is 1.7300 and the Differential constant (KD) is 0.0242 for the inner circle (C2). Outer ring controller (C1), the proportional constant (Kp) is 179,000 and the Differential constant (KD) is 2.4600. Cascade controllers and Proportional Differential controller types with First Order Filters in the Differential Section (PDF), the Proportional constant (Kp) value is 1.5900, the Differential constant (KD) value is 0.0246, the filter constant value (Tf) is 0.0018 for the inner circumference (C2 ). For the outer ring controller (C1), the Proportional constant (Kp) value is 134,0000, the Differential constant (KD) value is 2.2900 and the filter constant value (Tf) is 0.00008.

Macular and submacular choroidal microvasculature in patients with primary open-angle glaucoma and high myopia

AimsTo characterise the influence of primary open-angle glaucoma (POAG) and high myopia (HM) on the macular and choroidal capillary density (CD).MethodsTwo hundred and seven eyes were enrolled, including 80 POAG without HM, 50 POAG with HM, 31 HM without POAG and 46 normal controls. A fovea-centred 6×6 mm optical coherence tomography angiography scan was performed to obtain the CD of the superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris. Macular and choroidal CDs were compared among the groups and the association of CDs with visual field mean deviation (MD) was determined using linear regression models.ResultsCompared with normal eyes, SCP CD was decreased in the POAG without HM group (p<0.05), while DCP CD was significantly decreased in the HM without POAG group (p<0.05). Both SCP and DCP CDs were significantly decreased in the POAG with HM group (p<0.05). CD reduction occurred mainly in the outer rather than inner ring of the 6×6 mm scan size. In multivariate regression analysis, worse MD was associated with lower CD in the outer ring of the SCP in all the HM eyes (p<0.05).ConclusionsPOAG and HM reduced macular CD in different layers of the retinal capillary plexus and both particularly in the outer ring of the 6×6 mm scans. Furthermore, assessment of the CD in the outer ring of the SCP may facilitate the diagnosis of glaucoma in eyes with HM.

Local wisdom of communities around the forest and its implementation in the development of nature tourism on outer ring road of Lake Toba

Nature tourism can also act as one of the drivers of regional development and can be a window for efforts to introduce the potential of natural resources, values and culture owned by a country or a region. Therefore, the development of natural tourism is required to be able to mix forms of natural tourism that are attractive but unique and cover all aspects of locality in it. The purpose of this study was to examine the potential of local wisdom owned by the community around the forest and the implementation of local wisdom in the development of natural tourism along the outer ring of Lake Toba on the Merek Section. This research method is a form of descriptive qualitative research with information and data from various representative sources. The results of the study indicate that existing local wisdom includes wisdom that is tangible (textual, buildings, and objects of cultural heritage) and intangible (advice delivered orally and is passed down from generation to generation, and chanting or poetry that has traditional teaching values). These wise values are found in various sources such as the traditional house of the Karo Tribe in the Dokan Cultural Village, the Penusur Sira Ritual and the Joroh Joroh tourist attraction. The forms of implementation of local wisdom in the development of nature tourism include the application of an attitude of togetherness (mutual cooperation), kinship, courtesy, hospitality, concern for others, harmony with nature, problem solving system, active work, obedient to people and leaders, educational culture, conservation culture, concern for the environment, and values related to a culture of healthy living in the management of nature tourism.

Optimasi Desain Ban Tanpa Udara (Non Pneumatic Tire) Dengan Struktur Hexagonal Honeycombs Menggunakan Response Surface Method (RSM)

Non-Pneumatic Tires (NPT) are tires that do not use compressed air like other tires. In this paper, the optimal design obtained is based on the static and explicit dynamic behavior of the NPT construction, which has hexagonal honeycomb spokes. The hexagonal honeycomb type NPT component consists of the hub wheel, outer ring, spokes, and tread. The honeycomb model is made differently based on tread thickness (20 mm, 25 mm, 30 mm), outer ring thickness (0.25 mm, 0.5 mm, 0.75 mm), spokes thickness (3 mm, 5 mm, 7 mm), and the number of spokes holes (12, 13, 14). Based on the simulation results of Ansys and Minitab, the recommended optimal design is 20 mm tread thickness, 3.2 mm spokes thickness, 0.25 mm outer thickness, and the number of holes 12 pieces.

Analisis Beban Statis dan Explicit Dynamic Roda Tanpa Udara yang Menggunakan Hexagonal Honeycomb Spokes Pada Kendaraan Taktis TNI

Non-Pneumatic Tires (NPT) have been used in several sectors since the wide application and following with advantages of the simplicity in maintenance. In this paper, the static and explicit dynamic behavior of NPTs is investigated with several different honeycomb spokes. The component of NPT with a hexagonal honeycomb type consists of a hub wheel, outer ring, spokes, and tread. The six models of NPT are denoted with the variation of spokes thickness (20 and 30 mm) and thickness of the wheel tread (3, 5 and 7 mm). Based on the computer simulation results, the B3 type NPT has an excellent ability to accept loads with deformation, which is 14,358 mm and the stress is 270 MPa.

Maternal 3,3’-Diiodothyronine Sulfate Formation from Guinea Pig Placenta Perfused with 3,3’,5-Triodothyronine

Objective: Serum 3, 3’,5-triiodothyronine (T3) remains low in near-term fetus to prevent the growing fetus from undue exposure to its active catabolic effect in mammals. The present study was undertaken to gain insight in the role of placenta in T3 metabolism, fetal to maternal transfer of T3, and its metabolites by in situ placenta perfusion with outer-ring labeled [125I]-T3 in pregnant guinea pig, a species showing increased sulfated 3, 3’-diiodothyronine (T2S) levels in maternal serum in late pregnancy (term = 65 days), similarly to humans in pregnancy. Materials and Methods: One-pass placenta perfusions performed on pregnant guinea pigs were studied between 58 - 65 days of gestation. In two separate experiments, the umbilical artery of the guinea pig placenta was perfused in situ at 37°C with outer-ring labeled [125I]-T3. Maternal sera and umbilical effluents were obtained for analysis at the end of a 60-minute perfusion, when the steady-state levels of radioactivity were reached in the placenta effluent after 30-minute. Results: Sulfated [125I]-T2S was readily detected in the maternal serum as the major metabolite of T3 following the perfusion of placenta with [125I]-T3, suggesting that placental inner-ring deiodinase and sulfotransferase may play an important role in fetal T3 homeostasis and in the fetal to maternal transfer of sulfated iodothyronine metabolites. Conclusions: The expression of type 3 deiodinase (D3) and thyroid hormone sulfotransferase activity in placenta may play an important role to protect developing organs against undue exposure to active thyroid hormone in late gestation in the fetus. The combined activities of D3 and sulfotransferase promoted a placental transfer of T2S into maternal circulation. The maternal circulation of T2S is fetal T3 in origin and its role as a fetal thyroid function biomarker deserves further evaluations and studies.

EXAMINATION OF STRESS-STRAIN STATE OF SPHERICAL TRANSFORMING MECHANISM ELEMENTS AT NON-ORTHOGONAL ARRANGEMENT EXTERNAL HINGES

Work is devoted to modeling of stress-strain state of spherical converting mechanism with non-orthogonal arrangement of hinges of outer ring relative to rocking axis of intermediate ring. Results of simulation of mechanism main elements loading in operating position are shown. Based on the obtained data, the most hazardous areas were identified and design recommendations were given

Analysis of Temperature Characteristics of High-speed Rail Bearings based on Dynamics Model and Thermal Network Method

This paper establishes a dynamics model of the axle box bearing of high-speed trains. The model can obtain contact force and its change law. Between rollers and raceway when the bearing contains outer ring faults, inner ring faults, and rolling element faults. Based on the model, the thermal network method is introduced to study the temperature characteristics of axle box bearings of high-speed trains. In this model, the bearing can be divided into some isothermal nodes. The heat generation, conduction, and dispersion of these isothermal nodes can be solved. The results show that the temperature of the contact point between the outer ring raceway and the rolling elements is the highest. By analyzing the relationship between the node and the speed and fault size, it is obtained that the higher the speed, the higher the node temperature. When the fault size increases, the node temperature first increases and then decreases.

Designing vortices in pipe flow with topography-driven Langmuir circulation

We present direct numerical simulation of a mechanism for creating longitudinal vortices in pipe flow, compared with a model theory. By furnishing the pipe wall with a pattern of crossing waves, secondary flow in the form of streamwise vortex pairs is created. The mechanism, ‘CL1’, is kinematic and known from oceanography as a driver of Langmuir circulation. CL1 is strongest when the ‘wall wave’ vectors make an acute angle with the axis, $\varphi =10^{\circ }$ – $20^{\circ }$ , changes sign near $45^{\circ }$ and is weak and of opposite sign beyond this angle. A competing, dynamic mechanism driving secondary flow in the opposite sense is also observed, created by the azimuthally varying friction. Whereas at smaller angles ‘CL1’ prevails, the dynamic effect dominates when $\varphi \gtrsim 45^{\circ }$ , reversing the flow. Curiously, the circulation strength is a faster-than-linearly increasing function of Reynolds number for small $\varphi$ . We explore an analogy with Prandtl's secondary motion of the second kind in turbulence. A transport equation for average streamwise vorticity is derived, and we analyse it for three different crossing angles, $\varphi =18.6^{\circ }, 45^{\circ }$ and $60^{\circ }$ . Mean-vorticity production is organised in a ring-like structure with the two rings contributing to rotating flow in opposite senses. For the larger $\varphi$ , the inner ring decides the main swirling motion, whereas for $\varphi =18.6^{\circ }$ , outer-ring production dominates. For the larger angles, the outer ring is mainly driven by advection of vorticity and the inner by deformation (stretching) whereas, for $\varphi =18.6^{\circ }$ , both contribute approximately equally to production in the outer ring.