Studi Pengaruh Jumlah Rekahan Terhadap Kuat Tekan Uniaksial dan Kecepatan Gelombang Ultrasonik

Abstrak. Keberadaan rekahan merupakan keadaan yang umum terjadi dalam massa batuan. Pendeteksian rekahan dalam massa batuan merupakan hal yang sangat penting dalam pekerjaan pertambangan. Rekahan pada massa batuan secara umum mengurangi kekuatan dalam massa batuan tersebut. Salah satu metode yang umum digunakan dalam mendeteksi keberadaan rekahan adalah dengan non destructive test (NDT), yang mana menggunakan gelombang ultrasonik (kecepatan gelombang P/Vp) sebagai media pengukur. Vp merupakan parameter yang dipengaruhi oleh kebaradaan rekahan tersebut. Selain itu, dipelajari mengenai pengaruh rekahan terhadap nilai kuat tekan. Sampel yang digunakan merupakan beton dengan komposisi campuran semen – pasir 1:1 dan 1:3. Dua komposisi campuran tersebut dibuat sebagai representasi dari kekuatan batuan yang lemah dan kuat. Rekahan yang dibuat berupa rekahan artifisial pada sampel berukuran 5,4 cm x 12 cm dengan variasi jumlah rekahan untuk setiap komposisi.Kata Kunci: gelombang ultrasonik, kecepatan gelombang, rekahan, kuat tekan.Abstract. The existence of fractures is a common condition in rock masses. The detection of fractures in rock mass is very important in mining project. Fractures that existence in rock mass generally reduce strength of the rock masses. The methods commonly used in examining fractures is the non-destructive test (NDT), it’s use ultrasonic waves (P wave velocity) as measurement media. In this study discussed also the effect of fracture to the compressive strength. The sample used is concrete with a cement-sand mixture composition is 1: 1 and 1: 3. This two compositions represent the strength of rock, one mixture represent weak rocks and other mixture represent strong rocks. The fractures made as artificial fractures in the sample which sample dimension is 5.4 cm x 12 cm with a variation in the number of fractures for each composition.Keywords: ultrasonic wave, wave velocity, fracture, compressive strength

Numerical Evaluation of Earthquake Effect on Cisumdawu Tunnel Stability

Cisumdawu Tunnel is located approximately 3.95 km southeast of the activeLembang Fault. Earthquakes induced by movement of the the active the strike-slip fault may influence stability of the twin tunnel. This paper presents results of numerical analyses carried out to demonstrate effect of a worst-case scenario of earthquake load potentially induced by the Lembang Fault on the stability of the Cisumdawu Tunnel. Static and pseudo-static tunnel stability analyses were carried out at 11 observation stations of tunnel face mapping using RS2 finite element package (Rocscience, Inc.). In the pseudo-static analyses, a 0.48 horizontal seismic load coefficient, which was obtained from a deterministic seismic hazard analysis (DSHA) based on a 6.8 maximum magnitude of estimated earthquake sourced from the Lembang Fault using Campbell-Bozorgnia (2014) attenuation relationship, was applied to the finite element models. The numerical analysis results showed that strength factors of the rock masses around the twin tunnel were greater than unity, both under the static and earthquake loads. The forepolling zones, however, appeared to be under an overstressed condition. Reduction of rock strength factor around the tunnel roof due to application of the earthquake load occurred at all observation stations. Total displacement contours of rock masses around the twin tunnel indicated an increased rock mass displacement due to the earthquake load, as compared to that due to the static load. Under the static load, the largest displacement occurred at the tunnel inverts. The predicted roof displacements obtained from this study were in a reasonably good agreement with those obtained from the field measurements. Number of yielded elements and extend of shear and tension failure zones in the rock masses around the twin tunnel also appeared to increase due to the earthquake load. Despite slight tunnel displacement as predicted in the numerical analyses, the worst-case scenario of earthquake load potentially induced by the Lembang Fault may only cause failures of the rock masses around the Cisumdawu Tunnel. To prevent the twin tunnel displacement caused by such relatively severe earthquake loads, however, stabilizing surrounding the relatively poor ground condition may be necessary

PENGEMBANGAN DAN PERANCANGAN DESAIN CLOTHES CABINET PT. ATMI SOLO DENGAN SISTEM KNOCK-DOWN

AbstrakFurniture merupakan perlengkapan rumah tangga yang berfungsi untuk duduk, berbaring ataupun menyimpan pakaian. Clothes cabinet merupakan salah satu contoh produk furniture PT. ATMI Solo yang materialnya didominasi oleh plat baja yang berfungsi untuk menyimpan pakaian  atau barang pribadi. Kemajuan jaman menuntut perusahaan untuk menciptakan produk furniture yang memiliki sifat ringkas dan praktis, maka terciptalah desain clothes cabinet yang menerapkan konsep knock-down dengan sistem penguncian baut untuk menyatukan komponen – komponennya. Penerapan konsep knock-down dapat meningkatkan kepraktisan dan sifat ringkas dalam hal pengemasan produk sehingga dapat mengurangi biaya pengiriman. Desain clothes cabinetknock-down memiliki dimensi 1800 mm x 1000 mm x 500 mm dan dimensi produk produk saat dikemas adalah 1820 mm x 540 mm x 295 mm. Pengembangan rancangan produk clothes cabinetknock-down dapat mengurangi volume pengemasan sebesar 70%, meningkatkan kapasitas pengiriman sebesar 400% dan mengurangi biaya pengiriman dan pengemasan sebesar 47%.Kata kunci: furniture, knock-down, clothes cabinet, PT ATMI SoloAbstractFurniture is household equipment that functions to sit, lie down, or store clothes. A clothes cabinet is an example of PT. ATMI Solo, whose material is dominated by steel plates that function to store clothes or personal items. The progress of the times requires companies to create furniture products that are concise and practical, so a clothes cabinet design is created that applies the knock-down concept with a screw locking system to unite its components. Applying the knock-down concept can increase the practicality and concise nature of product packaging to reduce shipping costs. The knock-down clothes cabinet design has 1800 mm x 1000 mm x 500 mm, and the product dimensions when packaged are 1820 mm x 540 mm x 295 mm. Developing a knock-down clothes cabinet product design can reduce packaging volume by 70%, increase shipping capacity by 400% and reduce shipping and packaging costs by 47%.Keywords: furniture, knock-down, clothes cabinet, PT ATMI Sol

Genetic variation and genomic constitution in orchid Dendrobium hybrid section Spatulata derived from interspecific hybridization based on sequence related amplified polymorphism marker

Dendrobium hybrid section Spatulata is widely cultivated in Indonesia due to its ease of cultivation, high economic value and adaptability, also extended flower shelf life. Various attempts to meet the rising market demand for Dendrobium hybrid section Spatulata, including the development of new varieties with unique flower traits such as flower color, a longer and bigger horn, and disease resistance. In this study, we conducted a breeding program aimed at developing a new cultivar of Dendrobium hybrid section Spatulata (antelope orchids) through interspecific hybridization. The study aimed to investigate the genetic variation and genomic constitution of the eight hybrids and their corresponding parental lines that resulted from interspecific hybridization using sequence‐related amplified polymorphism (SRAP) marker. Six species of Dendrobium section Spatulata i.e., Dendrobium Sri Mulyani, D. Cochliodes, D. strepsiceros, D. stratiotes, D. Alice Noda, D. helix, and several hybrids of antelope orchids derived from three hybridizations including D. Sri Mulyani × D. cochliodes, D. stratiotes × D. strepsiceros, and D. Alice Noda × D. helix, respectively, were subjected into SRAP markers for genotyping analysis. Dendrobium hybrid section Spatulata hybrids produced by interspecific hybridization were genuine hybrids with substantial genetic variability based on flower morphology, including labellum shapes and color intensities, as well as curly horn shapes and color intensities. The SRAP marker, which was used to genotype the hybrid and parental lines, exhibited a significant degree of polymorphism, and might be used to distinguish each accession. It produced a unique DNA amplicon that ranged from 180 to 530 bp and inherited a certain progeny line. The unweighted pair group mean average (UPGMA) dendrogram and Principal Coordinate Analysis (PCoA) biplot showed that all the hybrids were grouped into three major clusters according to their corresponding parental lines based on their genetic background and ge‐ nomic constitution. These findings are critical for the genetic improvement of the Antelope orchid to develop novel varieties

Pemberdayaan Masyarakat dalam Upaya Peningkatan Kualitas Lingkungan Hidup Di Kelurahan Mangunharjo, Kecamatan Tugu, Kota Semarang

ABSTRAKWilayah Kelurahan Mangunharjo, Kecamatan Tugu, Kota Semarang memiliki beragam permasalahan yang bermuara dari tidak terpenuhinya kualitas lingkungan hidup. Kawasan Kelurahan Mangunharjo termasuk kawasan padat pemukiman. Warga sekitar masih belum menyadari pentingnya pengelolaan lingkungan pesisir sehingga menimbulkan penumpukan limbah sampah. Selain itu, kenaikan tinggi permukaan air laut memerlukan upaya pencegahan untuk tidak mengakibatkan abrasi. Permasalahan tersebut dapat diatasi dengan adanya kesadaran dari masyarakat umum sehingga lebih sadar akan kelestarian lingkungan pesisir. Untuk mencapai hal tersebut, dilaksanakan focus group discussion bersama warga mengenai upaya pelestarian lingkungan pesisir yang dilanjutkan dengan kegiatan aksi nyata. Kegiatan aksi nyata yang dilakukan yaitu kegiatan penyisiran sampah pesisir di area pantai dan penanaman mangrove. Hasil kegiatan ini adalah 110,27kg sampah terkumpul dengan dominasi sampah anorganik plastik dan sampah organic serta 600 bibit mangrove jenis Rhizopora mucronate telah ditanamn. Kegiatan pengabdian ini dilaksanakan selama enam bulan dan monitoring telah dilakukan sebanyak dua kali. Monitoring dilakukan untuk melihat perkembangan tanaman mangrove yang sudah ditanam dan kondisi sampah yang ada di pantai.Perlu adanya pengembangan terkait kegiatan ini untuk menciptakan lingkungan pesisir Pantai Mangunharjo yang terjaga eko sistemnya. Kata Kunci: lingkungan pesisir, limbah sampah, penyisiran sampah, penanaman mangrove ABSTRACTThe Mangunharjo Village area, Tugu District, Semarang City has various problems that stem from the lack of environmental quality. The Mangunharjo Village area is a densely residential area. Local residents still do not realize the importance of managing the coastal environment, resulting in a buildup of waste. In addition, rising sea levels require preventive measures to avoid causing abrasion. This problem can be overcome by raising awareness among the general public so that they are more aware of the sustainability of the coastal environment. To achieve this, a focus group discussion was held with residents regarding efforts to preserve the coastal environment, followed by real action activities. The real action activities carried out were sweeping coastal rubbish in coastal areas and planting mangroves. The results of this activity were 110.27 kg of waste collected, dominated by inorganic plastic waste and organic waste, and 600 Rhizopora mucronate mangrove seedlings were planted. This service activity was carried out for six months and monitoring was carried out twice. Monitoring is carried out to see the development of mangrove plants that have been planted and the condition of rubbish on the beach. There needs to be development related to this activity to create a coastal environment at Mangunharjo Beach whose ecosystem is maintained. Keywords: coastal environment, waste, trash sweeping, mangrove plantin

Rancang Bangun Sistem Aplikasi Monitoring Daya Listrik Rumah Berbasis Android

The need for household-scale electricity consumption is very closely dependent on household appliances that use electrical energy. The demand for household electricity has increased along with the Work From Home (WFH). If this is not managed optimally based on the aspect of its use, it will unconsciously have an impact on economic spending. The purpose of this study focuses on a prototype monitoring system for electrical quantities in the form of voltage, current strength and electric power in real time via the Android platform. The prototype that was created was able to collect realtime data every 1 minute and 5 minutes, respectively, resulting in a measurement accuracy of 92.99% and 81.85%. As well as reading accuracy of (36.60 + 2.42) Watt and (27 + 4.96) Watt. Based on the error results and the results of the reading accuracy of the prototype, a comparison was made between the delay of data retrieval per 1 minute and 5 minutes, it can be concluded that it has a higher reading accuracy per 1 minute. So that the suggestions and recommendations from further researchers regarding the design of electrical energy monitoring management use a delay time of more than one minute so as not to lose a lot of data information from the measurement results.Kebutuhan konsumsi listrik skala rumah tangga sangat bergantung pada peralatan rumah tangga yang menggunakan energi listrik. Kebutuhan listrik rumah tangga meningkat seiring dengan Work From Home (WFH). Jika hal ini tidak dikelola secara optimal berdasarkan aspek pemanfaatannya, secara tidak sadar akan berdampak pada pengeluaran ekonomi. Tujuan penelitian ini berfokus pada prototipe sistem monitoring besaran listrik berupa tegangan, kuat arus dan daya listrik secara real time melalui platform Android. Prototipe yang dibuat mampu mengumpulkan data secara realtime setiap 1 menit dan 5 menit, menghasilkan akurasi pengukuran sebesar 92,99% dan 81,85%. Serta akurasi pembacaan (36.60+2.42) Watt dan (27+4.96) Watt. Berdasarkan hasil error dan hasil akurasi pembacaan prototipe dibuat perbandingan antara delay pengambilan data per 1 menit dan 5 menit, dapat disimpulkan memiliki akurasi pembacaan per 1 menit yang lebih tinggi. Sehingga saran dan rekomendasi dari peneliti selanjutnya mengenai perancangan manajemen monitoring energi listrik menggunakan waktu tunda lebih dari satu menit agar tidak banyak kehilangan informasi data dari hasil pengukuran

PERHITUNGAN PRODUKSI OVERBURDEN DENGAN MENGGUNAKAN METODE OVERALL EQUIPMENT EFFECTIVENESS (OEE) DAN NILAI OEE DARI EXCAVATOR KOBELCO SK-200

PT. Starindo Sakti Award is the place to carry out this research which is located in Pangandaran. This study uses the Overall Equipment Effectiveness (OEE) method to optimize mining equipment in achieving production targets for overburden stripping. Overall Equipment Effectiveness (OEE) is a method that has been accepted globally to measure the level of a company and the potential for improvement of the production process. Overall Equipment Effectiveness (OEE) aims to evaluate the performance of an equipment used in industry. The factors to be calculated on the OEE component are: Availability Factor, Utilization Factor, Speed ​​Factor, Bucket Factor, Overall Equipment Effectiveness (OEE) of Equipment. The results of the calculation of overburden production using the OEE method after improving working time by reducing standby time and increasing operating hours, the overburden production obtained from the Kobelco SK-200 excavator is 20,160.22 BCM. While the Overall Equipment Effectiveness (OEE) value of the Kobelco SK-200 excavator after repairs is 60%