Impact of Invasive Ant Species in Shaping Ant Community Structure on Small Islands in Indonesia

Dampak Invasiv Species Semut pada Pembentukan Struktur Komunitas Semut di Kawasan Pulau-Pulau Kecil di Indonesia. Peneletian tentang pengaruh spesies invasif di kawasan pulau-pulau kecil menjadi perhatian konservasi yang sangat penting,teristimewa pengaruhnya terhadap fauna lokal dan teristimewa untuk semut-semut endemik yang menjadi kajian pada penelitian ini. Pada kajian ini penelitian dilakukan di tiga pulau yaitu Pulau Bokor, Rambut dan Untung Jawa. Semut diambil menggunakan metode pitfall trap. Metode penghitungan dengan model korelasi dan linier digunakan untuk mengukur penyebarannya secara acak di setiap pulau. Diperoleh tiga species invasif dua diantaranya yaitu Solenopsis geminata dan Paratrechina longicornis dapat dijumpai di ketiga pulau tersebut sedangkan untuk Anoplolepis gracilipes hanya dijumpai di Pulau Rambut. A. gracilipes dan S. geminata merupakan spesies yang melimpah dan komposisi keterdapatannya berkorelasi dengan faktor habitat (F2, 52 = 19.469, p<0.001)

Strength Investigation of Thick Welded T-Joint using Finite Element Modelling

The paper discusses the computation of finite element modelling (FEM) of a thick welded joint as a high load transfer joint. The FEM utilises MSC PATRAN/NASTRAN software programs to predict and simulate the critical area of a welded joint. The elasticity limit for the specimen was determined and stress distribution was achieved in the joint to indicate critical parts of a welded T-joint and predict the critical locations for crack initiation in this kind of joint. Simulation and experimental results show good in agreement and the sources of some differences in these results are discussed.Defence Science Journal, 2010, 60(1), pp.112-118, DOI:http://dx.doi.org/10.14429/dsj.60.11

The Effect of Automotive Side Member Filling on Car Frontal Impact Performance

To achieve lightweight design while retaining its crash performance, an aluminum alloy component filled with foam has been adopted as an alternative lightweight material. In the paper, the effect of different types of filling on the automotive side member is studied. Impact performance is compared in terms of the automobile energy absorbing capability and also its occupant safety, measured in terms of head injury criteria (Manning) and chest severity index (CSI). It is shown that the partially filled side member with values of 513.6 (HIC15), 677.3 (HIC36), 807.2 (CSI) and a weight of 5.45kg is found to yield lower potential of injury, and higher specific energy absorption (SEA) compared to an empty side member. It can be concluded that, even though the fully filled side member shows remarkable performance in terms of HIC, it increases the chances of injury to the chest. Future study can include different types of foam for performance improvement

Persebaran Agens Hayati Neochetina Spp. (Coleoptera: Curculionidae) Di Jawa Barat Dan DKI Jakarta

The establishment of Neochetina spp. as biocontrol agent of waterhyacinth are related to the weevil's ability to disperse and to increase their population sizes. The objective of this research was to study the distribution and abundance of Neochetina spp. at several areas in West Java and DKI Jakarta. The field research was done in several freshwater ecosystem infested by waterhyacinth, including Cibinong and Lido lakes in Bogor, irigation canal in Karawang, Muara Angke Sanctuary in North Jakarta, and Citarum Hulu river in Purwakarta, during April to August 2004. Coordinate and elevation of the research sites where N. eichhorniae and N. bruchi found were reported, while their abundances were observed by direct hand-collection technique. The results of the research showed that N. eichhorniae was widely distributed and established in most sampling sites, except in Karawang, whereas N. bruchi was not found in any sampling sites. Our observations also indicated that N. eichhorniae was distributed passively so that the weevil couldn't colonize isolated habitats or locations

Populasi Elaeidobius Kamerunicus Faust (Coleoptera: Curculionidae) pada Beberapa Umur Tanaman Kelapa Sawit

Elaeidobius kamerunicus Faust is an oil palm pollinator insect that lives on the male inflorescence and visits female inflorescence to pollinate due to attracted by its volatile compound. The number of fruit sets of oil palm relates to the population of E. kamerunicus on a plantation. The objective of this study was to investigate the effect of age of oil palm on the population of E. kamerunicus. Field research was conducted in oil palm plantations that located in Pangkalan Lada, Kotawaringin Barat District, in Central Kalimantan. The research method was by measurement of E. camerunicus population on male inflorescences and set up the sticky trap on female inflorescences. Plot with size 7000 m2 (100 trees) was selected on several ages of oil palm i.e. 6, 10 and 16 years. Each plot, the number of male and female inflorescences was counted and some inflorescences were chosen for measurement of E. camerunicus population that was conducted monthly for three months of observation. The results showed that the age of the oil palm affected the population of E. kamerunicus in male inflorescences but not in female inflorescences. The older age of oil palm, the population of E. kamerunicus in male flowers was increasing. The sex ratio of E. kamerunicus found in male and female inflorescences of oil palms tend to female bias. Based on the comparison of E. kamerunicus population between male and female inflorescences on each plot, it was found that visitation value of E. kamerunicus was highest in the young oil palm. In conclusion, increasing age of oil palm trees affected on increasing of E. kamerunicus population in male inflorescences, but visitation value on female inflorescences prone to decline

Pengaruh Habitat Sekitar Lahan Persawahan Dan Umur Tanaman Padi Terhadap Keanekaragaman Hymenoptera Parasitika

As the largest group of biological control agents, Parasitic Hymenoptera play important role in controlling pest outbreak in agricultural habitat. Unfortunately, there is lack of information about how these parasitoids occur in agricultural habitat related to condition of surrounding habitat and phenology of crop plant. The objective of this research was to study the effect of rice field surrounding habitat and age of rice plant on the diversity of Parasitic Hymenoptera. Research area was located in Carang Pulang Village, Dramaga, Bogor. We selected four blocks which represented different of habitat condition and age of rice plant. Each block was set six yellow pan traps (with minimum distance 20 meter) and one malaise trap. Sampling of insects were conducted weekly from 6 to 12 week after planting. From this research, we collected 1,833 individual of Hymenoptera (without ants) belong to 9 superfamilies, 23 families, and 216 species. Parasitic Hymenoptera was more abundant (96%) and species rich (84%) than Aculeata. Rice field surrounding habitat (block) and age of rice field significantly affect the diversity of Parasitic Hymenoptera. We found positively correlation between age of rice plant and species richness of Parasitic Hymenoptera

Keanekaragaman Semut Pada Persawahan Di Daerah Urban: Investigasi Pengaruh Habitat Sekitar Dan Perbedaan Umur Tanaman Padi

Agricultural intensification cause negative effect to insect diversity including beneficial insect such as natural enemies and pollinators. Habitat management through habitat heterogeneity is an alternative approach to protect insect diversity in agriculture area. In this study, we investigated the effect of habitat heterogeneity integrated with different age of crop plant in urban agricultural landscape to the ant diversity. The field research was conducted in agricultural area in Carang Pulang Village, Dramaga, Bogor. In around 6 ha area of rice field, grouped into four blocks which each block has different habitat condition and age of rice plant. In bunds of each block were put six pitfall traps with minimum distance 20 meter from each other. Ants were collected weekly from 6 until 12 weeks after planting to standardize the bunds condition. In total 22 species from 4 subfamilies of ants were recorded from this research. Iridomyrmex sp.01 and Odontoponera sp.01 are the common species which always found in each block and in different age of rice plant. There are no correlation between the distance of pitfall traps and similarity of ant species. In addition, habitat conditions surrounding rice field (block) significantly effect to the ant diversity. However, age of rice plant have no effect to the ant diversity

Short-term wind speed forecasting by an adaptive network-based fuzzy inference system (ANFIS): an attempt towards an ensemble forecasting method

Accurate Wind speed forecasting has a vital role in efficient utilization of wind farms. Wind forecasting could be performed for long or short time horizons. Given the volatile nature of wind and its dependent on many geographical parameters, it is difficult for traditional methods to provide a reliable forecast of wind speed time series. In this study, an attempt is made to establish an efficient adaptive network-based fuzzy interference (ANFIS) for short-term wind speed forecasting. Using the available data sets in the literature, the ANFIS network is constructed, tested and the results are compared with that of a regular neural network, which has been forecasted the same set of dataset in previous studies. To avoid trial-and-error process for selection of the ANFIS input data, the results of autocorrelation factor (ACF) and partial auto correlation factor (PACF) on the historical wind speed data are employed. The available data set is divided into two parts. 50% for training and 50% for testing and validation. The testing part of data set will be merely used for assessing the performance of the neural network which guarantees that only unseen data is used to evaluate the forecasting performance of the network. On the other hand, validation data could be used for parameter-setting of the network if required. The results indicate that ANFIS could not outperform ANN in short-term wind speed forecasting though its results are competitive. The two methods are hybridized, though simply by weightage, and the hybrid methods shows slight improvement comparing to both ANN and ANFIS results. Therefore, the goal of future studies could be implementing ANFIS and ANNs in a more comprehensive ensemble method which could be ultimately more robust and accurat