Ahmad Toha - Academia.edu (original) (raw)

Papers by Ahmad Toha

Buletin Ilmiah Sarjana Teknik Elektro

Air pollution continues to increase in Jakarta. The city ranks 12th in the world as the capital o... more Air pollution continues to increase in Jakarta. The city ranks 12th in the world as the capital of a country with high levels of pollution. The Jakarta Environmental Service requires processing air quality data generated by the Air Quality Monitoring Station in order to produce valuable information as a decision-making tool. This data processing can be processed with data mining techniques to seek new knowledge from the database so as to find valid, useful and easy-to-learn patterns. The SVM data mining classification model is proposed in this study. Our contribution in this research is to create a classification model with SVM with new techniques, namely improvements in data processing to perform hyperparameter tuning. We saw that previous researchers only pursued high accuracy scores. In contrast to previous studies, we used the gridsearch cv hyperparameter optimization technique on the SVM classification model. The kernel polynomial with 2 degrees is the best parameter recommenda...

Regional Dynamic: Journal of Policy and Business Science, 2020

TQM concept is known as a significant driver of performance of large-scale companies. This study ... more TQM concept is known as a significant driver of performance of large-scale companies. This study points out two perspectives namely direct and indirect influence associated with TQM. Specifically, it delves into the innovation and spiritual capital in improving the performance of Intako. Path analysis was carried out to shed lights on the correlation among the aforementioned aspects. There were 98 samples involved in the study. The research results confirm the influence of innovation and spiritual capital on TQM. Likewise, the same results are evident on the influence of innovation, spiritual capital, and TQM on company performance. Key word: Innovation, Spiritual Capital, Total Quality Management, Performance, Small-and-Medium Enterprises

Bulletin of the American Physical Society, 2015

suspended in turbulent fluid flows is of interest in view of the potential applications in indust... more suspended in turbulent fluid flows is of interest in view of the potential applications in industry and the environment. In the present work, we investigated the dynamics of inertia-free spheroidal particles suspended in fullydeveloped turbulent channel flow at Reτ = 180 by using the direct numerical simulations (DNS) for the Eulerian fluid phase coupled with the Lagrangian pointparticle tracking. We considered inertia-free spheroidal particles with a wide range of aspect ratios from 0.01 to 50, i.e. from flat disks to long rods. Although the spheroids passively translate along with the fluid, the particle orientation and rotation strongly depend on the particle shape. The flattest disks were preferentially aligned with their symmetry axis normal to the wall, whereas the longest rods aligned parallel to the wall. Strong mean rotational spin was observed for spherical particles and this has been damped with increasing asphericity both for rod-like and disk-like spheroids. The anisotropic mean and fluctuating fluid vorticity resulted in particle spin anisotropies which exhibited a complex dependence on the particle asphericty.

mengingat dokumen ini menjadi rujukan utama di dalam implementasinya, baik dalam pengajuan Work P... more mengingat dokumen ini menjadi rujukan utama di dalam implementasinya, baik dalam pengajuan Work Plan & Budget (WP&B) maupun Authorization for Expenditure (AFE). Untuk itu diperlukan kajian yang komprehensif dan terintegrasi agar dokumen tersebut dapat dijadikan rujukan yang akurat dan up to date. Penulisan studi ini merupakan pengkajian secara detil mengenai rencana pengembangan lapangan gas yang memiliki kandungan CO2 dan H2S yang tinggi. Kajian yang dilakukan mancakup kajian subsurface (dari mulai pemodelan geologi, simulasi reservoir dan skenario pengembangan), kajian fasilitas permukaan (berupa design facilitas yang diperlukan dan perkiraan biayanya) dan kajian keekonomian proyek (jadwal pengeluaran biaya dan parameter keekonomian proyek), sehingga diharapkan diperolah rencana usulan pengembangan yang optimum. Dari pemodelan geologi dan simulasi reservoir diperoleh hasil bahwa lapangan AS yang sour (CO2 27.5% & H2S 1.2%) ini memiliki cadangan hingga 360 BCF dengan recovery facto...

Bulletin of the American Physical Society, 2018

Investigation of cytotoxic effects of different ZnO nanostructures on living cancer cells / Racca... more Investigation of cytotoxic effects of different ZnO nanostructures on living cancer cells / Racca, Luisa; Dumontel, Bianca; Miccoli, Beatrice; Canta, Marta; Serpe, Loredana; Canaparo, Roberto; Di Benedetto, Cristiano; Falqui, Andrea; Cauda, Valentina Alice. STAMPA. (2016), pp. 158-158. ((Intervento presentato al convegno Merck Young Chemists Symposium (MYCS 2016) tenutosi a Rimini nel 25-27 novembre 2016. Original Investigation of cytotoxic effects of different ZnO nanostructures on living cancer cells

Gorham’s disease is a rare disorder characterized by progressive bone destruction and proliferati... more Gorham’s disease is a rare disorder characterized by progressive bone destruction and proliferation of vascular channels with replacement of fibrous connective tissue. The aetiology remains poorly understood while both diagnosis and management were challenging. We reported a case of an 18 year-old Ibanese girl of Sarawak with massive mandible destruction, whom initial complaint was gingival swelling of the right mandible with affected teeth mobility.

Journal of Indian Association of Pediatric Surgeons, 2019

Bulletin of the American Physical Society, 2014

fornia, Berkeley-We consider the rotational motion of non-spherical particles in turbulent flow, ... more fornia, Berkeley-We consider the rotational motion of non-spherical particles in turbulent flow, comparing the statistics of particles' angular velocity to the corresponding quantities computed in the fluid phase. We use numerical (DNS) and laboratory measurements for particles that are both larger and smaller than the Kolmogorov lengthscale. The particles are spheroids or rods, with aspect ratios between 1 and 10. We will discuss the subtleties of defining a meaningful Stokes number for these particles, focusing on the effect of asphericity and the fact that our interest is in rotation and not translation. Comparing the probability density function of angular velocity between fluid and particle phase indicates that the angular velocity of particles has a narrower distribution than that of the fluid phase, and that. particles do respond to extreme events in the fluid phase. The first four moments of the PDFs are analyzed, and these show that the "filtering" effect is very similar between DNS and lab experiments, despite differences in particle sizes and mass. We propose a nondimensional curve for predicting the magnitude of the filtering effect, and discuss the implications of this curve for the definition of Stokes number, as discussed earlier.

Journal of Fluid Mechanics, 2020

In homogeneous isotropic turbulence, slender rods are known to align with the Lagrangian stretchi... more In homogeneous isotropic turbulence, slender rods are known to align with the Lagrangian stretching direction. However, how the degree of alignment depends on the aspect ratio of the rod is not understood. Moreover, many flows of practical interest are anisotropic and inhomogeneous. Here we study the alignment of rods with the Lagrangian stretching direction in a channel flow, which is approximately homogeneous and isotropic near the center but inhomogeneous and anisotropic near the walls. Our main question is how the distribution of relative angles between a rod and the Lagrangian stretching direction depends on the aspect ratio of the rod and upon the distance of the rod from the channel wall. We find that the distribution exhibits two regimes: a plateau at small angles that corresponds to random uncorrelated motion, and power-law tails that describe large excursions. The variance of the relative angle is described by the width of the plateau. We find that slender rods near the channel center align better with the Lagrangian stretching direction, compared to those near the channel wall. These observations are explained in terms of simple statistical models based on Jeffery's equation, qualitatively near the channel center and quantitatively near the channel wall. Lastly we discuss the consequences of our results for the distribution of relative angles between the orientations of nearby rods (Zhao et al.,

Proc. Indon Petrol. Assoc., 36th Ann. Conv.

Journal of Global Oncology, 2018

Background: Pancreatic cancer is the fourth leading cause of cancer associated deaths in the Unit... more Background: Pancreatic cancer is the fourth leading cause of cancer associated deaths in the United States and ranks ninth in its incidence. EUS-guided FNA cytology has emerged as an important diagnostic tool since Vilman and Grimm (1992) made the first reports of endoscopic guided fine needle aspiration. Currently, EUS-guided FNA biopsy of the pancreas is a standard practice for the diagnosis and staging of pancreatic malignancy. Aim: The current study was carried out with the following objectives. 1. To find out the diagnostic accuracy, sensitivity, and specificity of EUS-guided FNA of the pancreatic malignancy by correlating cytologic diagnosis with histologic diagnosis and other investigations. 2. To know the diagnostic accuracy of air-dried smears using Diff-Quik Stain. 3. To compare the diagnosis obtained by Diff-Quik, conventional PAP Stain smears/cytospin preparation and Thin Prep (liquid-based media). Methods: 111 cases of EUS-guided FNA biopsy of the pancreas performed dur...

Frontiers in Cellular Neuroscience, 2018

Cywilizacja i Polityka, 2018

Poland in the period of post-1990s economic transformation did not create a vision of the functio... more Poland in the period of post-1990s economic transformation did not create a vision of the functioning of the maritime economy. It was considered that it is too small a sector of the economy to create its development programs. This was a mistake, as it stimulated socio-economic processes in coastal regions. This policy also led to the limited use of the territory of Poland as an important element of the European transport network, understood more broadly than the area of transit transport. It was only after 2012 that it was decided to prepare the maritime strategy as an operational strategy for state development programs.

International Journal of Multiphase Flow, 2017

PT. Ricobana Abadi merupakan badan usaha milik swasta yang bergerak di bidang pertambangan sebaga... more PT. Ricobana Abadi merupakan badan usaha milik swasta yang bergerak di bidang pertambangan sebagai kontraktor. Di lokasi penambangan Siluq Ngurai, Kalimantan Timur, PT. Ricobana Abadi melakukan penambangan pada sebuah proyek tambang yang dimiliki PT. Diva Kencana Borneo dengan kegiatan yang meliputi pembongkaran dan pemindahan tanah penutup dari front sampai disposal dan pengambilan batubara dari front sampai stockpile. Pembongkaran material keras dilakukan dengan menggunakan metode pemboran dan peledakan. Pemuatan saat ini pada panel 14 dilakukan dengan menggunakan excavator backhoe Komatsu PC 1250SP-8 sebanyak 2 unit dengan produktifitas per unit sebesar 414,9 bcm/jam, pengangkutannya menggunakan dump truck Komatsu HD 465-7R sebanyak 8 unit. Kondisi lebar jalan adalah 25 m-35 m, jarak angkut 0,8 km. Dengan kondisi tersebut produktifitas per unit sebesar 96,2 bcm/jam. Perusahaan menghadapi permasalahan dengan waktu kerja dan sistem pengoperasian alat. Perhitungan produktifitas teoritis excavator backhoe PC 1250SP–8 adalah sebesar 909,982 bcm/jam dan dump truck HD 465–7R sebesar 234,023 bcm/jam. Dengan waktu kerja dan kondisi kerja di lapangan saat ini, produktifitas alat mekanis yang dioperasikan diharapkan mampu mencapai hasil yang ditargetkan, excavator backhoe PC 1250SP–8 sebesar 500 bcm/jam dan untuk dump truck HD 465–7R adalah sebesar 100 bcm/jam sebagai persiapan menghadapi rencana naiknya target produksi. Upaya yang dilakukan untuk mengoptimalkan produktifitas dari alat muat dan alat angkut yang ada saat ini dilakukan dengan meningkatkan waktu kerja efektif dan pola pengoperasian alat yang meliputi pola penggalian dan pemuatan material. Pola penggalian dan pemuatan tersebut dilakukan dengan membentuk sudut putar 60° saat melakukan pemuatan dengan cara merubah penempatan alat muat atau alat angkut dengan memperhatikan front kerja, dengan demikian maka efisiensi pemuatan akan meningkat. Dari hasil peningkatan waktu kerja efektif dan pembenahan pengoperasian kerja alat, diperoleh peningkatan produktifitas.Pada lokasi yang sama untuk alat muat produktifitasnya yang semula 414,9 bcm/jam menjadi 500,98 bcm/jam, sedangkan pada alat angkut produktifitasnya yang semula 96,2 bcm/jam menjadi 101,41 bcm/jam. Maka produktifitas maksimal dari rangkaian kerja alat muat dan alat angkut dapat optimal. Seiring dengan kemajuan penambangan maka produktifitas alat akan berubah karena jarak angkut yang berubah. Kemajuan penambangan maju mendekati lokasi penimbunan, sehingga produktifitas akan relatif semakin besar. PT. Ricobana Abadi is a privately owned company engaged in the mining sector as a contractor. In Siluq Ngurai mine in East Kalimantan, PT. Ricobana Abadi mining on a mining project owned by PT. Diva Kencana Borneo with activities that include the dismantling and removal of overburden from the front to the disposal and collection of coal from front to stockpile. Demolition of hard material made using drilling and blasting methods. Loading the panel 14 is currently done using excavator backhoe Komatsu PC 1250SP-8 as 2 units with productivity per unit of 414.9 bcm/h, transportation using a dump truck Komatsu HD 465 -7R as 8 units. The condition of the road width is 25 m-35 m, 0,8 km transport distance. Under these conditions the productivity per unit of 96.2 bcm/hour. The company faces problems with working time and operating system tools. The calculation of theoretical productivity excavar torbackhoe PC 1250SP-8 is at 909.982 bcm/h and dump truck HD 465- 7R at 234.023 bcm/hour. With time and working conditions in the field today, productivity-operated mechanical device is expected to achieve targeted results, excavator backhoe PC 1250SP-8 of 500 bcm / h and for dump truck HD 465-7R amounted to 100 bcm / h in preparation for the planned increase in production targets. Efforts are underway to optimize the productivity of the tool loading and transport equipment that is currently done by increasing the effective working hours and patterns covering the operation of the excavation and loading pattern material. The pattern of excavation and loading is done by forming the swivel angle of 60° during loading by changing the placement of equipment load or conveyance with respect to front of work, and thus will increase the loading efficiency. From the result of an increase in effective working time and work improvement tool operation, acquired increased produktifitas.Pada same location for unloading productivity tool that was originally 414.9 bcm / h to 500.98 bcm / h, while the productivity of the original conveyance 96.2 bcm / h to 101.41 bcm / hour. So the maximum productivity from a series of work load and conveyance equipment can be optimized. Along with advances in mining productivity tool that will change due to the changing distance transport. Progress forward to the landfill mining, so the productivity will be relatively greater

Karya Ilmiah Mahasiswa S1 Sistem Informasi, Nov 10, 2011

Daerah Istimewa Yogyakarta (DIY) adalah salah satu propinsi yang memiliki statusistimewa atau oto... more Daerah Istimewa Yogyakarta (DIY) adalah salah satu propinsi yang memiliki statusistimewa atau otonomi khusus dari 33 propinsi di Indonesia. Keistimewaan DIY tersebutmembuat tata kelola dan peraturan daerah di DIY berbeda dengan propinsi lain di Indonesiadalam hal Struktur Pemerintah Daerah, Pemilihan Kepala Daerah dan Sistem Kepegawaian.Keistimewaan tersebut merupakan ketetapan dan kesepakatan sejak awal berdirinya NegaraKesatuan Republik Indonesia (NKRI). Yogyakarta pertama kali berstatus provinsi pada 5September 1945, ketika Raja Ngayogyakarto Hadiningrat Sri Sultan Hamengku Buwono IXbersama Paku Alam VIII menyatakan bahwa Negeri Ngayogyakarto Hadiningrat adalah bagiandari Negara Kesatuan Republik Indonesia (NKRI) yang diproklamirkan Soekarno Hatta pada 17Agustus 1945. Amanat Sri Sultan bersama Paku Alaman yang kemudian disebut Amanat 5September tersebut merupakan bentuk dukungan Kerajaan Ngayogyakarto Hadiningratterhadap NKRI.Amanat 5 September 1945 tersebut antara lain berisi berintegrasinya KerajaanNgayogyakarto Hadiningrat dan Kadipaten Paku Alaman dengan NKRI, tentang Ketika Indonesiadiproklamasikan sebagai suatu negara merdeka oleh Soekarno Hatta, sebenarnya KerajaanYogyakarta dan begitu juga kerajaan-kerajaan lain di wilayah bekas jajahan Belanda bisa sajamelepaskan diri dari NKRI. Namun ternyata Sri Sultan Hamengku Buwono IX dan Paku Alam VIIImemberikan dukungan terhadap NKRI dan dalam amanat yang ditandatangani Sri Sultanbersama Paku Alam menyatakan Keistimewaan Yogyakarta ini pun disambut baik oleh parafounding father Indonesia dengan dikeluarkannya payung hukum yang dikenal dengan namapiagam penetapan. Payung hukum ini sebenarnya sudah dikeluarkan oleh Soekarno yang dudukdi BPUPKI dan PPKI pada tanggal 19 Agustus 1945.Konsekuensi dari hal tersebut berarti pemimpin (gubernur dan wakil gubernur) ProvinsiYogyakarta adalah raja Ngayogyakarto Hadiningrat dengan wakilnya adalah raja dari Paku Alam,yang selama ini dijabat Sri Sultan Hamengku Buwono IX dan Paku Alam VIII dan kemudiandilanjutkan (baca diwariskan) kepada Sri Sultan Hamengku Buwono X dan Paku Alam IX. Kondisiini berlangsung damai sampai kemudian muncul Undang-Undang Nomor 32 tahun 2004tentang Pemerintah Daerah. Dalam UU tersebut, diatur bahwa gubernur dan wakil gubernursuatu provinsi di NKRI dipilih dalam pemilihan kepala daerah (pilkada) dengan masa jabatanmaksimal 10 tahun atau dua kali pilkada.Pemerintah yang terkesan memaksakan kehendak untuk merubah tatanan dalamperaturan propinsi Daerah Istimewa Yogyakarta dan merubah silsilah atau kekuasaankesultanan dengan Undang-Undang Nomor 32 tahun 2004 tersebut, telah menimbulkanpolemik di berbagai kalangan. Hampir semua kalangan di Yogyakarta tetap menginginkankeistimewaan Yogyakarta sehingga jika Pemerintah tetap memaksakan perubahan terutamapada proses pemilihan kepala daerah, bias menyebabkan terjadinya kemarahan masyarakatterhadap pemerintah yang dianggap mengkhianati amanat 5 September 1945. Hal tersebutdapat menyebabkan berbagai permasalahan yang dapat mengancam persatuan dan keutuhanNKRI.