Semesta Teknika最新文献

{"title":"Analisa Perbandingan Efisiensi Sistem Struktur Pelat-Balok dengan Sistem Struktur Flat Slab-Drop Panel pada Proyek Jogja Apartment","authors":"Y. A. Harsoyo, Ervan Nurfiansyah","doi":"10.18196/ST.V23I1.7612","DOIUrl":"https://doi.org/10.18196/ST.V23I1.7612","url":null,"abstract":"Sistem struktur dalam dunia konstruksi bangunan gedung bertingkat memiliki banyak metode dan system struktur oleh karena itu perencana harus memilih sistem struktur yang sesuai dengan kebutuhannya. Pada proyek Jogja Apartment digunakan sistem flat slab-drop panel, sistem pelat tersebut masih jarang digunakan dalam perancanaan gedung. Penelitian ini dilakukan untuk membandingkan antara sistem flat slab-drop panel dan sistem pelat-balok yang ditinjau dari segi biaya pelaksanaan, waktu pelaksanaan, dan desain strukturnya. Penelitian dilakukan dengan cara mendesain ulang satu denah pelat gedung Jogja Apartment dengan menggunakan sistem flat slab-drop panel dan sistem pelat-balok dengan metode dan pembebanan yang sama. Metode yang digunakan dalam mendesain kedua sistem pelat tersebut adalah metode desain langsung dengan peraturan SNI 03-2847-2013 sebagai dasar perhitungannya. Dari hasil penelitian didapat bahwa sistem flat slab-drop panel memiliki biaya sebesar Rp3.552.429.292 lebih murah 24,52% dibandingkan menggunakan sistem pelat-balok sebesar Rp4.706.334.233. Untuk waktu pelaksanaan sistem flat slab-drop panel memiliki waktu lebih cepat 2 hari dibandingkan dengan sistem pelat-balok. Sistem flat slab-drop panel memiliki tinggi ruang bebas yang lebih tinggi dibandingkan dengan sistem pelat-balok Many types of structural systems in the construction world of a multi-storey building make planners choose a structural system that suits their needs. Jogja Apartment project used a flat slab-drop panel system. It is rarely used in building planning so this study conducted to compare the flat slab-drop panel system and the plate-beam system in terms of implementation costs, implementation time, and structural design. The study was conducted by redesigning one plate layout of the Jogja Apartment building by using the flat slab-drop panel system and the plate-beam system using the same method and loading. The method used in designing the two plate systems is a direct design method based on SNI 03-2847-2013. This study found that the flat slab-drop panel system has a cost of Rp 3.552.429.292, it is 24,52% cheaper than using a plate-beam system (Rp 4.706.334.233). The flat slab-drop panel has a faster time of 2 days to build compared to the plate-beam system in the implementation time. The flat slab-drop panel system has a higher free space compared to the plate-beam system in structural design.","PeriodicalId":33667,"journal":{"name":"Semesta Teknika","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48197481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kuat Tekan Beton dan Nilai Penyerapan dengan Variasi Perawatan Perendaman Air Laut dan Air Sungai","authors":"As’at Pujianto, Hakas Prayuda, Berkat Cipta Zega, Besty Afriandini","doi":"10.18196/ST.222243","DOIUrl":"https://doi.org/10.18196/ST.222243","url":null,"abstract":"Penelitian ini membahas pengaruh dari perawatan beton menggunakan air laut dan air sungai terhadap karakteristik beton. Tujuan dari penelitian ini untuk menjelaskan pengaruh dari jenis air pada perawatan beton, khususnya pada beton yang digunakan yang berhubungan langsung dengan air. Pada penelitian ini menggunakan tiga jenis produk semen yaitu Holcim, Tiga Roda dan Gresik dengan total 12 variasi dan 108 benda uji berbentuk silinder berdiameter 15 cm dan tinggi 30 cm. Seluruh variasi menggunakan standar mix design yang sama dengan 6 variasi menggunakan perbedaan jumlah superplasticizer dan 6 variasi menggunakan bahan tambah fly ash . Pengujian yang dilakukan berupa pemeriksaan workabilitas, kuat tekan dan nilai penyerapan. Hasil pada pengujian ini menunjukkan bahwa nilai workabilitas pada beton menggunakan superplasticizer lebih baik dibandingkan beton menggunakan bahan tambah fly ash . Hasil kuat tekan menunjukkan bahwa seluruh benda uji dengan perawatan air laut lebih tinggi dibandingkan dengan beton menggunakan perawatan air sungai. Sedangkan nilai penyerapan menunjukkan bahwa pada umur 28 hari dengan menggunakan air laut menghasilkan nilai yang lebih tinggi dibandingkan perawatan menggunakan air sungai. This study will discuss the effect of concrete treatment using sea water and river water on the characteristics of concrete. The purpose of this study was to determine the effect of water types in concrete treatment, especially for concrete used directly in contact with water. In this study three types of cement brands, Holcim, Tiga Roda and Gresik were used with a total variation of this study as many as 12 with the number of test specimens of 108 cylindrical concrete measuring 15cm in diameter and 30 cm in height. All variations use the same mix design and then modified with 6 variations using super-plasticizer added material while the remaining 6 variations use material added admixture in the form of fly ash which then carried out workability testing, compressive strength and percentage of absorption. The results of this study indicate that the level of concrete workability using superplasticizer added material is much better than using materials added by fly ash. The results of the compressive strength obtained showed that almost all specimens with soaking seawater had a higher compressive strength than concrete with treatment with river water. Absorption results show that at 28 days the seawater absorption rate is greater than river water.","PeriodicalId":33667,"journal":{"name":"Semesta Teknika","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46387623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pelaksanaan Inspeksi Keselamatan pada Perlintasan Sebidang JPL 349 KM 163+758, Jalan Timoho, Yogyakarta","authors":"Noor Mahmudah, Dian M Setiawan, Ristacya Devi Ramanti","doi":"10.18196/ST.222242","DOIUrl":"https://doi.org/10.18196/ST.222242","url":null,"abstract":"Kecelakaan yang terjadi antara kendaraan jalan raya dan kereta api dapat terjadi di perlintasan sebidang walaupun sudah dilengkapi dengan prasarana yang telah ditentukan. Penelitian ini bertujuan untuk menginspeksi keselamatan perlintasan sebidang di JPL 349, Jalan Timoho, Yogyakarta, karena lokasi perlintaasan sebidang ini berdekatan dengan pusat kegiatan masyarakat. Metode penelitian ini diawali dengan studi pustaka dan pengumpulan data primer dan data sekunder. Data primer terdiri dari data kelengkapan infrastruktur, data geometrik, volume lalulintas, tundaan lalulintas, panjang antrian kendaraan, dan indeks kondisi struktur perkerasan ( Pavement Condition Index ). Sementara itu, data sekunder berupa jadwal kedatangan dan keberangkatan kereta api. Hasil penelitian ini menunjukkan bahwa perlintasan sebidang JPL 349 tidak memenuhi persyaratan yang berlaku terkait dengan rambu, marka, interval waktu kedatangan kereta api, sudut perpotongan perlintasan, jarak antara perlintasan sebidang yang berdekatan, dan alinemen horizontal. Tundaan lalulintas terlama ialah sebesar 194 detik dan antrian kendaraan terpanjang ialah 210 meter. Selain itu, disimpulkan bahwa nilai indeks kondisi struktur perkerasan ialah sebesar 72.9% (sangat bagus). Accidents between motorized vehicles and trains may occur at level crossings even though it has been maintained and given an adequate infrastructure. This study aims to conduct a safety inspections at JPL 349, Timoho Street, Yogyakarta since the level crossing location close to the center of human activity. This research method begins with a literature study and primary and secondary data collection. The primary data consisted of infrastructure completeness data, highway and rail track geometric, traffic volume, traffic delay, vehicles queue length, and pavement condition index (PCI). While secondary data was in the form of train departure and arrival schedules. The conclusions of this study stated that the JPL 349 level crossing do not meet the applicable regulatory standards in terms of signs, markers, train travel time intervals, intersection angles between highway and rail track, and the distance between level crossings. In terms of geometric, the horizontal alignment of the highway was also not in accordance with the applicable regulations. The longest traffic delay was 194 seconds and the longest queue of vehicles was 210 m. In addition, it was known that the average PCI was 72.9% (very good).","PeriodicalId":33667,"journal":{"name":"Semesta Teknika","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48561068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Redesain Kolom Segiempat Ke Kolom Lingkaran Pada Gedung Kejaksaan Tinggi Riau","authors":"A. Usman, Y. A. Harsoyo","doi":"10.18196/st.222247","DOIUrl":"https://doi.org/10.18196/st.222247","url":null,"abstract":"Fasilitas perkantoran banyak dibangun di Indonesia mulai dari kantor untuk pemerintahan hingga swasta. Kantor dibangun sebagian besar menggunakan kolom pada umumnya yakni kolom berpenampang persegi. Penampang kolom dengan bentuk lain yakni kolom lingkaran, kolom ini ketika berada dilapangan pada perkantoran jarang digunakan sehingga peneliti melakukan penelitian yang bisa menjadi saran bahwa kolom lingkaran baik digunakan pada bangunan kantor dari segi biaya, tulangan dan beban gempa. Redesain dilakukan pada gedung Kejaksaan Tinggi Riau dimana yang redesain pada kolom utama K1. Perancangan ulang dibantu dengan Etabs 2016 serta SNI 2847:2013, SNI 1726:2013, SNI 1727:2013 dan peraturan lain. Salah satu langkah menjadi pembeda dari penelitian lain diagram interaksi 1%-6% dibuat secara manual berdasarkan SNI 2847:2013 untuk penentuan persen tulangan utama kolom. Penelitian membuahkan hasil dimana kolom lingkaran dari biaya lebih murah 48,7% dari persegi. Kebutuhan tulangan utama lebih kecil dari persegi dengan persentase 3,13%. Sengkang 85,08 persen lebih kecil lingkaran. Kinerja menahan beban gempa kolom lingkaran hampir menyamai dengan persegi dengan selisih displacement pada arah x dan y sebesar 0,0001 m. Sehingga dari hasil disimpulkan bahwa kedepannya dalam membangun sebuah gedung kantor tidak hanya menggunakan kolom persegi sebagai kolom utama tetapi juga dapat menggunakan kolom lingkaran sebagai kolom utama. Office facilities have been built in Indonesia ranging from offices for government to private. The office was built mostly using columns in general, square columns. Column cross-section with another form that is a circle column, this column when in the field in offices is rarely used so researchers conduct research that could be a suggestion that the circle column is good for office buildings in terms of cost, reinforcement and earthquake load. The redesign was carried out at the Riau High Prosecutors building where the redesign was in the main column K1. The redesign was assisted with Etabs 2016 and SNI 2847: 2013, SNI 1726: 2013, SNI 1727: 2013 and other regulations. One step becomes a differentiator from other studies 1% -6% interaction diagram created manually based on SNI 2847: 2013 for determining the main percent reinforcement column. The research yielded results where the circle column of the cost is 48,7% cheaper than the square. The need for major reinforcement is smaller than a square with a percentage of 3,13%. Brace 85,08 percent smaller circle. The performance of withstanding earthquake column circle loads is almost equal to square with displacement difference in the x and y directions of 0,0001 m. So from the results concluded that in the future in building an office build not only uses a square column as the main column but also can use the circle column as the main column .","PeriodicalId":33667,"journal":{"name":"Semesta Teknika","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48717106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulation of High Viscosity Gas-Liquid Two-Phase Flow in a Horizontal Mini Pipe","authors":"S. Sukamta","doi":"10.18196/ST.222241","DOIUrl":"https://doi.org/10.18196/ST.222241","url":null,"abstract":"Two-phase flow is used in many industries such as nuclear reactors, boilers, condensers, liquefactions of natural gas, etc. Two-phase flow is a flow in a pipe which has two states of fluid such as solid-liquid, liquid-gas, gas-solid. In a two-phase flow, there are three channels, namely vertical, horizontal and inclined channels. In the horizontal channel, the most widely found flow is the flow patterns of stratified flow, bubble flow, plug flow, stratified wavy flow, annular flow, and slug flow. Refer to the previous research above, the flow patterns were mostly obtained by using an experimental study. The advantage of using the simulation is the ability to predict the flow pattern and pressure gradient before doing the experimental study so it can be known earlier if it will have an insecure flow pattern, i.e. slug flow. This research was conducted to find the flow pattern and pressure gradient by using a Computational Fluid Dynamics (CFD) software, the Ansys Fluent 19.0 Student. The model which was used is the Volume of Fluid (VOF) with the fluid of air-water and glycerin (40%-70%). The length of the pipe was 200 mm, the inner diameter was 1.6 mm, and the length of the test section was 100 mm. Liquid superficial speeds (J L ) of 0.033 m/s; 0.149 m/s; 0.232 m/s; 0.539 m/s; 0.7 m/s; 2.297 m/s and 4.935 m/s were used, while the air superficial speed (J G ) was 9.62 m/s. The result of the simulation showed slug annular and churn flow patterns. Slug annular was formed at J L = 0.033 m/s; 0.149 m/s and 0.232 m/s with the glycerin content of 40% and 50%. Slug annular pattern was formed when the glycerin content was 60% and 70% with J L = 0.539 m/s. Viscosity affects the flow pattern, the higher the glycerin content, the higher the viscosity and the more fluid than air. The higher the J L and glycerin content, the higher the pressure gradient.","PeriodicalId":33667,"journal":{"name":"Semesta Teknika","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43745134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Klasifikasi Cacat Lintasan Dalam Bantalan Bola Berbasis Support Vector Machine (SVM) pada Fan Industri","authors":"B. P. Kamiel, Arie Joko Wiranto, Bambang Riyanta, Sulis Yulianto","doi":"10.18196/ST.222246","DOIUrl":"https://doi.org/10.18196/ST.222246","url":null,"abstract":"Fan adalah sebuah mesin industri yang berfungsi  mensirkulasikan udara di dalam sebuah ruangan. Salah satu komponen dari fan yang sering rusak adalah bantalan. Metode spektrum merupakan salah satu metode deteksi rusak/cacat bantalan berbasis getaran yang umum digunakan namun grafik spektrum sering sulit dipahami oleh operator di lapangan. Metode pengenalan pola ( pattern recognition ) adalah metode yang mudah digunakan karena tidak perlu menterjemahkan grafik spektrum. Metode pengenalan pola yang digunakan pada penelitian ini adalah Support Vector Machine (SVM). Tujuan penelitian ini adalah mendeteksi cacat lintasan dalam pada bantalan bola. Penelitian ini menggunakan dua kondisi bantalan yang berbeda yaitu bantalan normal, dan bantalan cacat. Cacat pada bantalan dibuat dengan metode Electrical Discharge Machine (EDM) pada lintasan dalam dengan kedalaman 1,4 mm dan lebar 0,4 mm. Sinyal getaran bantalan direkam dari rig uji fan industri menggunakan software MATLAB dengan merekam data sebanyak 700 file untuk setiap kondisi. Data tersebut diektraksi kedalam 17 parameter statistik yang kemudian diseleksi secara visual sebagai input SVM. Klasifikasi SVM dilakukan dengan variasi kernel Radial Basis Function (RBF), Polynomial dan Linear . Hasil penelitian menunjukkan parameter statistik entropy dengan standart error menggunakan variasi kernel Radial Basis Function (RBF), Polynomial dan Linear adalah rekomendasi untuk klasifikasi cacat pada bantalan lintasan dalam karena menghasilkan akurasi sebesar 100%. Industrial fan is one of - rotating machine ry commonly used by industr ies to circulate air in a particular area . One of the most important component of a fan is the bearing which may fault during its operation S pectrum analysis  is one of vibration-based methods frequently used to detect faulty bearing  but this method has a disadvantage that is not easily understood by operators in the field. Pattern recognition method  is an easy method to be used because it does not need to interpret the spe c trum. The pattern recognition method used in this study is Support Vector Machine (SVM). The purpose of this study is to detect inner race fault of a ball bearing using SVM. This study uses two different bearing s , namely a normal bearing and a faulty bearing. Fault on the bearing were made by Electrical Discharge Machine (EDM) on the inner race with a width of 0 . 4 mm  and a depth of 1.4 mm. The test is carried out on an industrial fan test rig and recorded using MATLAB . The vibration signal is recorded to result of 700 files for each bearing condition. The vibration data is subsequently extracted into 17 statistical parameters which are then visually selected as input of SVM classifier. The SVM classifiear is trained using variations of the Radial Basis Function (RBF), Polynomial and Linear kernels. The results show s that the statistical parameters of e ntropy -s tandard e rror using variation of the RBF, Polynomial and Linear kernels gives the highes","PeriodicalId":33667,"journal":{"name":"Semesta Teknika","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44344797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analisis Pengaruh Sloof terhadap Penurunan Fondasi Telapak dengan Simulasi Numeris","authors":"Muh. Handy Dwi Adityawan, Agus Darmawan Adi, Ashar Saputra","doi":"10.18196/ST.222245","DOIUrl":"https://doi.org/10.18196/ST.222245","url":null,"abstract":"Sloof yang menghubungkan dua kolom selama ini diperhitungkan sebagai balok ikat (tie beam) agar kolom tidak bergeser. Sloof diasumsikan menggantung atau tidak bertumpu di atas tanah. Sehingga sloof murni sebagai pengikat antar dua kolom. Namun, kenyataan di lapangan sloof bertumpu di atas tanah atau di atas pasangan batu. Oleh karena itu sloof akan menerima beban vertikal dari bangunan. Desain sloof perlu diubah karena kondisi ini. Analisis dilakukan dengan menggunakan program SAP2000. Tanah dan pasangan batu dimodelkan sebagai spring dengan input parameter modulus reaksi tanah dasar (ks). Hasil analisis menunjukkan bahwa penurunan fondasi telapak pada kondisi sloof bertumpu di atas tanah atau di atas pasangan batu lebih kecil dibandingkan kondisi sloof menggantung. Selisih penurunan rata-rata sekitar 26%. Beda penurunan dan angular distortion antara dua kolom menjadi lebih kecil ketika sloof bertumpu di atas tanah atau di atas pasangan batu dibandingkan kondisi sloof menggantung. Momen lapangan yang bekerja pada sloof menggantung adalah positif sedangkan momen tumpuan adalah negatif. Sebaliknya, momen lapangan yang bekerja pada sloof bertumpu di atas tanah maupun di atas pasangan batu adalah negatif, sedangkan momen tumpuan adalah positif. Sloof connecting two columns has been calculated as a tie beam to keep them from moving apart. It was assumed as the hanging sloof or not rested on the ground. Hence it was purely as a tie between two columns. However, in the field, sloof is rested on the ground or the stone foundation. Therefore the sloof will receive the vertical load of the building. The sloof design need to be changed due to this condition. An analysis was conducted using SAP2000. The ground and the stone foundation were modeled as springs at which the modulus subgrade reaction (ks) was the input parameters. The results showed that the settlement of footing when the sloof resting on the ground or the stone foundation was smaller than the hanging sloof. The difference of the settlement was about 26% on average. Differential settlement and angular distortion between two column footings became smaller when the sloof was rested on the ground or the stone foundation compared to the hanging sloof. The field bending moment that occurred on the hanging sloof was positive, while the restraint moment was negative. In contrary, the field bending moment that occurred on the sloof rested on the ground or the stone foundation was negative, while the restraint moment was positive. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ \u0000 table.MsoNormalTable \u0000 {mso-style-name:\"Table Normal\"; \u0000 mso-tstyle-rowband-size:0; \u0000 mso-tstyle-colband-size:0; \u0000 mso-style-noshow:yes; \u0000 mso-style-priority:99; \u0000 mso-style-parent:\"\"; \u0000 mso-padding-alt:0cm 5.4pt 0cm 5.4pt; \u0000 mso-para-margin:0cm; \u0000 mso-para-margin-bottom:.0001pt; \u0000 mso-pagination:widow-orphan; \u0000 font-size:10.0pt; \u0000 font-family:\"Calibri\",sans-serif; \u0000 mso-bidi-font-family:\"Times New Roman\";","PeriodicalId":33667,"journal":{"name":"Semesta Teknika","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46411185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pengaruh Kecepatan Putar Tool dan Sudut Shoulder Sambungan Friction Stir Spot Welding pada Bahan Polypropylene","authors":"Aris Widyo Nugroho, M. Saputra, Cahyo Budiyantoro","doi":"10.18196/st.222250","DOIUrl":"https://doi.org/10.18196/st.222250","url":null,"abstract":"Penyambungan bahan thermoplastic polypropilen dengan teknik Friction stir spot welding (FSSW) telah banyak dilakukan. Walaupun kekuatannya sudah mencukupi, masih dihasilkan keyhole dan bekas shoulder yang cukup besar karena penggunaan ukuran soulder dan pin besar. Penelitian ini menginvestigasi sambungan polypropilen dengan teknik FSSW menggunakan shoulder dan pin lebih kecil pada geometri shoulder yang berbeda. Penelitian di awali dengan pemotongan lembaran polypropylene dengan panjang 150mm, lebar 30mm dan tebal 5mm. Sambungan tumpang sesuai dengan standar EN 12814-2 digunakan dalam penyambungan ini. Proses penyambungan dilakukan pada kecepatan putar 985, 1660, 2350 rpm dengan dua jenis tool (shoulder angle 0o dan 5o). Sambungan diamati struktur makro, kekerasan dan kapastas beban tariknya. Hasil penelitian menunjukan bahwa semua sambungan memiliki kegagalan getas. Seiring bertambahnya sudut shoulder dan kecepatan putar tool, ukuran nugget dan welding zone meningkat, sehingga meningkatkan kapasitas beban tari mencapai 2116 N. Geometri tool 2 berpotensi untuk dapat diaplikasikan dalam sambungan FSSW. The joining of thermoplastic polypropylene material using the Friction stir spot welding (FSSW) technique has been developed. Although the strength is sufficient, it still produces a large keyhole and shoulder marks due to the use of a large shoulder and pin size. This research investigates polypropylene joint with the FSSW technique using smaller shoulders and pins on different shoulder geometries. The research began by cutting of polypropylene sheets into 150 mm long and 30 mm wide and 5 mm thick. Specimens according to EN 12814-2 were used in this welding joint. The welding process is carried out at rotational speeds of 985, 1660, 2350 rpm with two types of tools (shoulder angle of 0o and 5o). The welding joint was then observed for macrostructure, hardness, and tensile load-bearing capacity. The results showed that all welding joints had a brittle failure. The increasing of the shoulder angle and the rotational speed increase the nugget size and welding zone thickness resulting in a higher tensile load-bearing capacity which reaches up to 2116 N. The tool with the geometric being used has the potential to be applied in the FSSW joint.","PeriodicalId":33667,"journal":{"name":"Semesta Teknika","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48557481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pengaruh Komposisi Biodisel Jagung Terhadap Sifat-Sifat Campuran Biodisel Jatropha-Jagung","authors":"W. Wahyudi, Andre Sasuta, Muhammad Nadjib","doi":"10.18196/st.222249","DOIUrl":"https://doi.org/10.18196/st.222249","url":null,"abstract":"Biodisel merupakan bahan bakar alternatif untuk mesin disel yang biasanya terbuat dari minyak nabati. Minyak jatropha dan minyak jagung merupakan bahan baku biodisel yang potensial. Namun biodisel dari bahan baku minyak jatropha memiliki kelemahan, diantaranya adalah viskositas yang relatif tinggi dan nilai kalor yang relatif rendah. Salah satu upaya perbaikannya adalah pencampuran dengan minyak jagung. Penelitian ini bertujuan untuk mengetahui pengaruh dari variasi komposisi campuran terhadap karakteristik biodisel. Kedua jenis bahan baku diproses menjadi biodisel melalui reaksi transesterifikasi. Selanjutnya dilakukan pencampuran antara biodisel jatropha dan biodiesel jagung. Campuran dibuat dalam sembilan variasi komposisi. Setiap komposisi campuran diaduk dan dipanaskan pada suhu 90 °C selama 60 menit. Hasil penelitian menunjukkan bahwa campuran biodisel jatropha dan jagung memiliki viskositas yang lebih rendah daripada biodisel jatropha murni. Densitas dan titik nyala campuran biodisel tersebut juga mengalami penurunan. Hasil lainnya adalah nilai kalor biodiesel campuran lebih tinggi daripada nilai kalor biodiesel jatropha murni. Biodiesel is an alternative fuel for diesel engines that are usually made from vegetable oil. Jatropha and corn oil are potential biodiesel feedstocks. However, biodiesel from jatropha oil has disadvantages, including high viscosity and relatively low heating value. An effort to improve its properties is mixing it with corn oil. The purpose of this study was to determine the effect of the composition of the mixture on the biodiesel properties. Both raw materials were processed into biodiesel through transesterification reactions. The next step is mixing jatropha and corn biodiesel. There were nine variations of the biodiesel mixture. Each mixture was stirred and heated at 90 °C for 60 minutes. The results showed that the mixture of jatropha and corn biodiesel had lower viscosity than pure jatropha biodiesel. Density and flash point of the biodiesel mixture also decreased. The heating value of mixed biodiesel is higher than its of pure jatropha biodiesel.","PeriodicalId":33667,"journal":{"name":"Semesta Teknika","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45889081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kuat Tekan Vertikal Dinding Panel Beton Expanded Polystyrene dengan Perkuatan Papan Kalsium Silikat dan Penyambung Geser Baut","authors":"Bella Lutfiani Al Zakina, A. Saputra, A. Awaludin","doi":"10.18196/st.222248","DOIUrl":"https://doi.org/10.18196/st.222248","url":null,"abstract":"Perlunya percepatan penyediaan rumah tinggal mengharuskan pemerintah mencoba sistem konstruksi inovatif menggunakan sistem beton sandwich polystyrene yang digunakan sebagai konstruksi dinding. Konstruksi ini memiliki kelebihan seperti memiliki bobot yang relatif lebih ringan, harga yang relatif lebih ekonomis, dan kemudahan serta kecepatan konstruksi. Konstruksi ini diharapkan dapat mengurangi risiko kerusakan akibat gempa bumi karena memiliki bobot yang relatif ringan yang merupakan salah satu syarat untuk rumah tahan gempa. Untuk meningkatkan daya dukung dinding panel beton polystyrene agar menjadi dinding struktural, alternatifnya adalah menggunakan bahan pelapis perkuatan. Dalam penelitian ini menggunakan spesimen pracetak yang diperoleh dari pracetak pabriksi dengan panjang 1800 mm, lebar 610 mm, dan tebal 75 mm. Penguatan menggunakan papan Kalsium Silikat. Jenis kalsium silikat yang digunakan adalah papan Kalsi. Benda uji disabung menggunakan lem sika dan kemudian dilubangi, jika telah dilakukan pasang bautsebagai konektor geser. Variasi dalam penelitian ini adalah panel beton polystyrene polos, panel beton polystyrene yang diperkuat dengan kalsi, dan panel beton polystyrene yang diperkuat dengan kalsi dan konektor geser baut. Pengujian berdasarkan SNI 03-3122- 1992 (Panel Beton Ringan Berserat). Hasil penelitian menunjukkan bahwa nilai rata-rata berat panel adalah 612,57 kg / m3, modulus elastisitas 942,37 MPa, kekuatan tekan 2,52 MPa dan kapasitas penyerapan air 12,11%. Kekuatan tekan tertinggi diperoleh oleh panel dengan perkuatan kalsiboard sebesar 1,18 MPa. Ini menunjukkan penambahan lapisan perkuatan akan mempengaruhi peningkatan kekuatan. The need to acceleration the provision of residential homes requires the government tried innovative construction system using concrete sandwiches expanded polystyrene used as wall construction. This construction has advantages such as having a relatively lighter weight, relatively more economical prices, and the ease and speed of construction. This construction is expected to reduce the risk of damage due to earthquakes because it has a relatively light weight which is one of the requirements for earthquake resistant houses. To increase the bearing capacity of expanded polystyrene concrete panel walls to be a structural wall, the alternative is to use reinforced coating material. In this study using precast specimens obtained from the precast manufacturing with a length of 1800 mm, width 610 mm, and thick 75 mm. Strengthening using the Calcium Silicate board. The type of calcium silicate used is the Kalsi board. The test object is glued using sika glue and then drilling, if it is has done to install the bolt as a sliding connector. Variations in this study are expanded polystyrene concrete panels without reinforcement, with reinforcement, and with reinforcement and bolt shear connectors. Testing based on SNI 03-3122- 1992 (Fibrous Lightweight Concrete Panel). The results showed that the average val","PeriodicalId":33667,"journal":{"name":"Semesta Teknika","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46557354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}