The design of the sampling parameters for CMM of free-form surfaces

In order to improve the inspection accuracy of free-form surface by CMM, this paper adopted the different sampling parameters to research the influence of the measurement accuracy of free-form surface. Through the combination of area uniform block random sampling and Latin hypercube random sampling, the minimum sampling grid block area and ball diameter were taken as the research parameters. Firstly, this research analysed theoretically the influence of measurement accuracy of free-form surface by different sampling parameters. Secondly, carrying out experiments verified the analytical results. Then, the influence of two groups of sampling parameters on the normal deviation of free-form surface could be acquired by analysing the experimental data. Finally, this research could obtain the result of normal deviation of free-form surface. The research results showed that the minimum block area of sampling and the diameter of measuring ball become smaller, and the profile error become larger when the number of measuring points were the same, the more it can reflect the actual contour of the free-form surface, which proves that the measurement accuracy is higher.

Exploration of Arbuscular Mycorrhizal Fungi from Sugarcane Rhizosphere in Marginal Land

The exploration of arbuscular mycorrhiza fungi from sugarcane plantation in marginal land in South Sulawesi was carried out to find the source of inoculums showing effective infection. Soil samples were taken from four area with different characteristic of marginal land, namely land with low organic matter content, clay texture, limited irrigation, and undulating land. Mycorrhizae contained in the soil samples were then observed, and the spores obtained were used as the source of isolation by a single spore culture. The mycorrhizal spores were isolated by wet sieving and centrifugation method with 48% sucrose, which were observed under a compound microscope for spore details (100-1000x). Sugarcane root samples were taken to observe mycorrhizal infection in sugarcane root tissue by root staining method. The results of the study showed that the greatest diversity of mycorrhizal genera was found in soil samples of Jambua Block (Glomus, Gigaspora, and Sclerocistis) and AJ-5 Block area (Glomus, Acaulospora, and Sclerocistis). Single-spore isolates obtained were Glomus sp. and Acaulospora sp. Infection test result on four sugarcane varieties commonly grown in Takalar Sugar Factory showed that infectivity of mycorrhizal isolate of Acaulospora sp. was the highest (75%) and significantly different (LSD’test, p 0,05) compared to that of Glomus sp. (66%).

The Impact of Fracture Persistence and Intact Rock Bridge Failure on the In Situ Block Area Distribution

The in situ block size distribution is an essential characteristic of fractured rock masses and impacts the assessment of rockfall hazards and other fields of rock mechanics. The block size distribution can be estimated rather easily for fully persistent fractures, but it is a challenge to determine this parameter when non-persistent fractures in a rock mass should be considered. In many approaches, the block size distribution is estimated by assuming that the fractures are fully persistent, resulting in an underestimation of the block sizes for many fracture geometries. In addition, the block size distribution is influenced by intact rock bridge failure, especially in rock masses with non-persistent fractures, either in a short-term perspective during a slope failure event when the rock mass increasingly disintegrates or in a long-term view when the rock mass progressively weakens. The quantification of intact rock bridge failure in a rock mass is highly complex, comprising fracture coalescence and crack growth driven by time-dependent changes of the in situ stresses due to thermal, freezing-thawing, and pore water pressure fluctuations. This contribution presents stochastic analyses of the two-dimensional in situ block area distribution and the mean block area of non-persistent fracture networks. The applied 2D discrete fracture network approach takes into account the potential failure of intact rock bridges based on a pre-defined threshold length and relies on input parameters that can be easily measured in the field by classical discontinuity mapping methods (e.g., scanline mapping). In addition, on the basis of these discrete fracture network analyses, an empirical relationship was determined between (i) the mean block area for persistent fractures, (ii) the mean block area for non-persistent fractures, and (iii) the mean interconnectivity factor. The further adaptation of this 2D approach to 3D block geometries is discussed on the basis of general considerations. The calculations carried out in this contribution highlight the large impact of non-persistent fractures and intact rock bridge failure for rock mass characterization, e.g., rockfall assessment.

Resources Estimation on further Exploration activities in PT. Trimegah Bangun Persada (Harita Group) Kawasi Village, South Halmahera District, North Maluku

PT. Trimegah Bangun Persada intends to do mining activity at the north part of IUP as the south and west parts have already been mined. This research aimed at producing natural resources of laterite nickel in the advanced exploration activity of Tangkuban Block. Besides, it also compared and determined the estimation methods having a good correlation with drilling results. Tangkuban Block carried out core drilling within total drill numbers of 286 spots and space distance 25 meters at the block area 22.16 Ha. This research began with determining the geological domain consisting of limonite, saprolite, and bedrock through a geo-statistical approach. After that, the researcher estimated nickel resources by three methods namely ordinary kriging, inverse distance weight, and nearest neighbor point. The result of estimation by ordinary kriging obtained a total volume of limonite layer 1,345,313 m3 with the content average of 1%, while the total volume of saprolite layer was 1,850,000 m3 1.64%.

Distribution of the T12 erector spinal muscle plane block in the dorsal region guided by ultrasound

Background This study aimed to explore the distribution of the erector spinal muscle plane block of the thoracic 12 vertebral body (T12) in the dorsal region guided by ultrasound. Methods A total of 28 patients, who underwent elective lumbar surgery, were enrolled in the present study. These patients were aged between 18 and 65 years, and the American Society of Anesthesiologists (ASA) grade was 1 or 2. The block of the T12 transverse process erector spinal muscle was performed under the guidance of ultrasound, and each side was injected with 25 ml of 0.4% ropivacaine hydrochloride + 2 mg of dexamethasone. The back areas were measured using the cold-warm method (the back area was divided into 11 areas [T7–S1] with the body surface marker). At 10, 20, 30, 40, 50, and 60 min after the drug injection, the effectiveness of the regional block was recorded. The presence of puncture hematoma, local anesthesia drug poisoning, nausea, vomiting, headache, and dizziness after the block was recorded. Results The range of the T12 transverse process block was basically fixed at 30 min after the single injection. No pneumothorax, hematoma, or local anesthetic poisoning occurred in any of the patients. Conclusion The effective longitudinal plane of the T12 transverse process erector spinal muscle block was mainly distributed in the T9–L5 dorsal cutaneous branches, and the distribution of the block area was safe and stable.

Efektivitas Tata Letak Gudang Baru untuk Menekan Tingkat Kerusakan Produk Menggunakan Metode Class Based Storage

Abstract— U.D. BAROKAH is engaged in the fulfillment of agricultural needs that will move products from the old warehouse to the new warehouse, products include: fertilizers (subsidies and non-subsidies), seeds, and pesticides. The old warehouse with an area of 150m2 and a new warehouse that has an area of 400m2. To streamline the new space and hopefully can reduce the level of damage to the product then, layout layout design is made using 2 methods of ABC classification and Class Based Storage Method. The product is placed in accordance with its activities, looking at the demand of November 2017 which shows the percentage value close to grade A 80%, B15%, and C5% grade. So make the area block based on the class, the area of the block area used class A 49m2, B 14m2, and C10m2. From the results calculated to determine the effectiveness of the warehouse mathematically by using the calculation of Material Handling Cost, the result of the calculation is Rp 375.321,60 per month.Keywords : ABC Classification , Class Based Storage, and Material Handling Cost Abstrak— U.D. BAROKAH yang bergerak dalam bidang pemenuhan kebutuhan pertanian yang akan memindahkan produk dari gudang lama ke gudang yang baru, produk meliputi: pupuk (subsidi dan non subsidi), bibit, dan pestisida. Gudang lama dengan luas 150m2 dan gudang baru yang mempunyai luas 400 m2. Untuk mengefektifkan luas ruangan baru dan diharapkan bisa menekan tingkat kerusakan pada produk maka, perancangan tata letak layout dibuat menggunakan 2 metode yaitu klasifikasi ABC dan Metode Class Based Storage. Produk ditempatkan sesuai dengan aktifitasnya, melihat dari permintaan bulan November 2017 yang menunjukan nilai persentase mendekati untuk kelas A 80%, B 15% , dan kelas C 5%. Sehingga di buatlah blok area berdasarkan kelas tersebut, luas block area yang terpakai kelas A 49 m2, B 14m2, dan C 10 m2. Dari hasil tersebut dihitung untuk mengetahui efektifitas gudang secara matematis dengan menggunakan perhitungan Ongkos Material Handling, hasil dari pehitungan tersebut adalah Rp 375.321,60 per bulan.Kata kunci : Klasifikasi ABC, Class Based Storage, Ongkos Material Handling