Assessment on pastoral system within oil palm - cattle integrated system to support beef self-sufficiency in North Sumatra

The research was conducted to see the forage production, carry capacity and rotation cycle that was most suitable for grazing cattle in the ecosystem of oil palm plantations. The research was conducted at Tanah Itam Ulu Oil Palm Plantation, Tanah Itam Ulu Village, Lima Puluh District, North Sumatra from January-December 2017. The research used RCBD consisting of 3 x 3 with 3 replications. The first factor is the age of oil palm trees (6, 12 18 years), the second factor is the rotation cycle of forage (40, 50, 60 days). The parameters observed: forage production, cattle capacity, forage nutritional and botanical composition. The research results showed that forage production and carrying capacity had a significantly higher effect (P <0.05) with a harvest interval of 40 days at the location of juvenile oil palm, which was 11,962 kg dry matter /ha/year and carrying capacity was 1.31 AU/ha. Forage quality (protein, NDF and ADF) had no significant effect (P> 0.05). The dominant forage species appeared in almost all observation plots, namely Cyrtococcum and Axonopus. The results of the study concluded that oil palms of 12 years with a harvest rotation of 40 days provided the largest capacity for grazing beef cattle.

POTENSI WISATA ALAM DI KOTA PAGAR ALAM, PROVINSI SUMATERA SELATAN BERDASARKAN PENAWARAN, PERMINTAAN DAN DAYA DUKUNG

Pagar Alam City belongs to the administrative region of South Sumatera Province and has a variety of natural tourism to be developed. This research focuses on determining natural tourism potentials based on supply, demand and carry capacity in Pagar Alam City. The assessment used the analysis of potential objects and natural attractions using the guidelines for regional analysis of operations-objects and natural attractions (ADO- ODTWA) from Directorate General of Forest Protection and Nature Conservation (2003) and carrying capacity’s analysis using the formula Douglass (1982). The results showed that Pagar Alam city has 7 natural tourism potential dan 29 natural tourism enough potential with the highest potency value index of the Dempo Mountain Tea Plantation Area 87.89% and the lowest 33.51% is Blange Water Fall. The number of tourists according to carrying capacity for each tourism activities are recreational activities 1.041.336 people/year and camping activities 555.685 people/year.Keywords: demand, carrying capacity, natural tourism, supply, tourist.AbstrakKota Pagar Alam termasuk dalam wilayah Provinsi Sumatera Selatan dan memiliki berbagai wisata alam untuk dikembangkan. Fokus penelitian adalah kajian potensi wisata alam di Kota Pagar Alam, Sumatera Selatan berdasarkan penawaran, permintaan dan daya dukung di Kota Pagar Alam. Penilaian yang digunakan adalah analisis potensi objek dan daya tarik wisata alam menggunakan pedoman analisis daerah operasi-objek dan daya tarik wisata alam (ADO-ODTWA) Direktorat Jendral Perlindungan Hutan dan Konservasi Alam (2003) dan analisis daya dukung menggunakan formula Douglass (1982). Hasil penelitian menunjukkan bahwa Kota Pagar Alam memiliki 7 wisata alam yang berpotensi dan 29 wisata alam cukup berpotensi untuk dikembangkan dengan indeks nilai potensi tertinggi yaitu Kawasan Perkebunan Teh Gunung Dempo dengan persentase 87.89% dan terendah 33.51% yaitu Cughup Blange. Jumlah wisatawan sesuai dengan daya dukung untuk masing-masing kegiatan wisata yaitu kegiatan rekreasi adalah 1.041.336 orang/tahun dan kegiatan wisata 555.685 orang/tahun.Kata kunci: daya dukung, penawaran, permintaan, wisawatan, wisata alam

The Effect of Concrete Footing Shape in Differential Settlement: A Seismic Design

This paper presents the numerical results of concrete footing-soil foundation seismic interaction mechanism. The concrete footing has been made with two different shapes, but with the equal volume of concrete material. The concrete footing-soil foundation has been analyzed using nonlinear finite elements, with the fixed-base state. The simulated near-fault ground motions have been applied to the concrete footing-soil foundation. The problem has been formulated based on the settlement controlled analysis. The local geotechnical conditions of all configurations have been analyzed. The numerical analysis results indicate that the shape of a concrete footing alters seismic response, revises inertial interaction, enhances damping ratio, improves load carry capacity, modifies cyclic differential settlement, revises failure patterns, minimizes nonlinear deformation, and changes cyclic strain energy dissipation. The novelty of this research work is the strain energy has more been dissipated with artistic concrete footing design.

KAJIAN KUALITAS AIR DALAM EVALUASI PENGEMBANGAN PERIKANAN DI WADUK IR. H. DJUANDA, JAWA BARAT

Budi daya ikan di Waduk Ir. H. Djuanda (A=8.300 ha, Zmax=95 m, dan Z=36,5 m) berkembang sangat pesat, sehingga berdampak pada penurunan kualitas air. Tujuan penelitian ini adalah untuk mengevaluasi kualitas air bagi kepentingan perikanan dan mengidentifikasi sumber tekanan tertinggi di Waduk Ir. H. Djuanda. Pengambilan data dilakukan setiap bulan dan tahun 2004 sampai dengan 2006. Pengamatan kualitas air dilakukan dengan metode pengambilan contoh air secara horisontal dan vertikal. Hasil penelitian menunjukkan bahwa sumber utama degradasi kualitas air adalah bahan organik yang berasal dari Waduk Cirata. Distribusi vertikal oksigen terlarut di perairan menunjukkan ada stratifikasi dengan kedalaman epilimnion yang sangat tipis. Berdasarkan pada analisis kandungan fosfat dan nitrogen, waduk ini telah mengalami perubahan dari eutrofik (tahun 2004) menjadi hipereutrofik (tahun 2005 dan 2006). Degradasi tersebut cenderung meningkat seiring dengan peningkatan jumlah unit karamba jaring apung yang dikembangkan di Waduk Cirata dan Waduk Ir. H. Djuanda. Kondisi ini menunjukkan bahwa pengembangan kegiatan budi daya dalam karamba jaring apung telah melampaui daya dukung dan cenderung mencemari perairan. Upaya mengatasi degredasi tersebut dapat dilakukan dengan 2 cara, yaitu 1) mengurangi usaha budi daya ikan dalam karamba jaring apung di Waduk Ir. H. Djuanda dan Cirata dan 2) menebarkan jenis ikan yang mampu memanfaatkan plankton secara efektif. Development of fish culture in Ir. H. Djuanda Reservoir has been expanded very fast, so it might cause the degradation of water qualities. The aims to evaluated water quality for fisheries purpose and identify the primary pressure source in Ir. H. Djuanda Reservoir. The data were collected every month during year of 2004 to 2006. Water sampling was done by vertical and horizontal. The result indicates that the primary source degradation of water qualities was organic materials from Cirata Reservoir. Stratification of dissolved oxygen in the water column indicates with very thin epilimnion layer. Based on phosphate and N-compuonds analysis, Ir. H. Djuanda Reservoir was changed from eutrophic in year 2004 to hipereutrophic in year 2005 and 2006. The degradation tends to increase with developing floating cage unit numbers in Cirata and Ir. H. Djuanda Reservoir. This condition shows that the development of fish culture in floating cage seems have be over the carry capacity of reservoir and tend to spread the pollution in the water. It effort suggest that the would two ways, i.e. 1) decrease of fish culture activities using be done refering floating cages in Ir. H. Djuanda and Cirata Reservoir and 2) stocking of fish species which are capable to utilized the plankton effectively.

Multivariate Optimization of Fiber Reinforced Laminate Using Ant Colony Optimization Algorithm

Fiber reinforced laminate design is a challenging problem in the field of composite laminates. It provides us a systematic way to design the laminates of desired properties while conveniently incorporating the thick-ness and mass constraints. In this paper, we pursue the multivariate graphite fiber reinforced laminate design problem using Ant Colony Optimization (ACO) algorithm. Classical lamination theory is used to determine mid-plane strains, curvatures and stresses in individual lamina under applied biaxial loading conditions. The fiber orientations, lamina thickness, number of layers and fiber volume fractions of lamina are considered as the optimization variables. Failure of the lamina is analyzed by Tsai–Wu failure criterion. Objective of the study is to maximize the load carry capacity of the composite laminate structure and minimize the areal mass density under multivariate/multiobjective optimization.

Effect of Clearance on Thermodynamic Characteristics of Woven Liner Spherical Plain Bearing

The mechanical property of woven liner spherical plain bearing in different clearance has been analyzed using the finite element software. It indicated that when the positive clearance of woven liner spherical plain bearing is 100um, the maximum stress of its inner ring is the lowest. The position of the maximum stress is in the middle of the inner ring. That makes the bearing has a bigger carry capacity. Based on above analysis, the thermal properties between the friction pair of woven liner spherical plain bearing which clearance is 100um is also analyzed. The node temperature variation trend of inner ring and liner along with the analysis process is obtained.