PENGARUH JARAK (GAP) TERHADAP KEKUATAN GESER PADA SAMBUNGAN TORCH BRAZING DENGAN FILLER PADUAN PERAK

Penelitian ini dilakukan untuk mengetahui kekuatan geser pada sambungan brazing lap joint dengan variasi jarak (gap) pada logam induk. Brazing adalah suatu proses penyambungan dua atau lebih logam oleh logam pengisi dengan memanaskan daerah sambungan di atas 450°C (temperatur cair logam pengisi) tanpa mencairkan logam induknya. Bahan yang digunakan sebagai logam induk adalah C-Mn dan logam pengisi brazing adalah logam perak (Ag-40Cu-0,1Ni-0,3Ti). Proses brazing yang digunakan pada penelitian ini adalah torch brazing. Kekuatan geser diuji sesuai dengan AWS C3.2:2001. Permukaan patah benda uji, dianalisa dengan menggunakan foto makro dan mikro. Hasil pengujian menunjukkan bahwa kekuatan geser semakin meningkat dengan adanya variasi jarak (gap) sambungan. Kekuatan geser terbesar (72,50 Mpa) diperoleh pada jarak (gap) 0,1 mm.Terjadinya reaksi penetrasi dan cacat sambungan mempengaruhi kekuatan geser. Reaksi penetrasi paling baik terjadi pada jarak (gap) 0,1 mm

Pengaruh Variasi Turbo Cyclone pada Saluran Udara Masuk Terhadap Unjuk Kerja Mobil Avanza Veloz Tahun 2012

Turbo cyclone is an additional tool used in the engine combustion which serves to change the flow of air in the intake manifold becomes swirl. This study investigated the performance effect of the engine combustion in the form of torque, mean effective pressure, and the power between an engine that do not use turbo cyclone with an engine that utilizes turbo cyclone. In addition, this study has purpose to get a good design of turbo cyclone for engine combustion of gasoline 1500 cc. This study used type of research design. It designed a turbo cyclone with variation in the type of blade and number of blades. This research uses experimental method. This research utilized turbo cyclone that has been made in the design prior to the testing for comparing the performance of engine combustion without turbo cyclone in standard condition with the performance of using turbo cyclone on the air duct before the throttle body. The independent variable of this study is the use of turbo cyclone with 3 types of blade perforated (type B3), turbo cyclone with 6 types of blade perforated (type B6), turbo cyclone with 3 types of blade not perforated (type A3), and turbo cyclone with 6 types of blade not perforated (type A6). While, this research observed the performance of the engine combustion in the form of torque, mean effective pressure, and power as the dependent variable. The result showed that the highest torque is 149,6 Nm at 4000 rpm on the use of turbo cyclone type B3. The result of the highest mean effective pressure is 1288,51 kPa at 4000 rpm. While, performance of highest power in the engine combustion standard without the use of turbo cyclone is 85,79 kW at 6000 rpm. The best design to be applied on the gasoline engine of 1500cc is turbo cyclone type B3. Keywords: Power, Swirl, Turbo Cyclon

Vibrating soap films: An analog for quantum chaos on billiards

We present an experimental setup based on the normal modes of vibrating soap films which shows quantum features of integrable and chaotic billiards. In particular, we obtain the so-called scars -narrow linear regions with high probability along classical periodic orbits- for the classically chaotic billiards. We show that these scars are also visible at low frequencies. Finally, we suggest some applications of our experimental setup in other related two-dimensional wave phenomena.Comment: 5 pages, 7 figures. Better Postscript figures available on reques

Pengaruh Ketebalan Lapisan Isolator Sio2 terhadap Mobilitas Lubang dari Transistor Efek Medan Organik Pentacene

Saat ini, riset tentang divais elektronik yang memakai bahan organik banyak dilakukan. Divais elektronik organik memiliki banyak kelebihan dibandingkan dengan divais elektronik silikon seperti kelenturan dan lain-lain. Untuk kali ini, akan dijelaskan pengaruh ketebalan lapisan isolator gerbang (G) SiO2 terhadap karakteristik transfer (ID-VG) dan karakteristik penguatan (ID-VD) dari transistor efek medan organik yang telah difabrikasi. Pertama, lapisan isolator SiO2 ditumbuhkan dengan menggunakan metode oksidasi termal dengan ketebalan 100 nm - 500 nm. Selanjutnya, sebagai bahan semikonduktor organik, pentacene dideposisikan dengan ketebalan 50 nm pada suhu ruang dengan metode evaporasi termal pada kevakuman 8×10-6 Torr. Terakhir, terminal source dan drain dibentuk dari emas dengan metode evaporasi termal dengan ketebalan 30 nm. Panjang kanal dan lebar kanal dari transistor masing-masing adalah 200 µm dan 500 µm. Hasil pengukuran karakteristik ID-VD menunjukkan bahwa mobilitas lubang meningkat dari 0.03 cm2/(Vs) ke 0.1 cm2/(Vs) seiring berkurangnya ketebalan SiO2 dari 500 nm ke 100 nm

Analisa Simulasi Kinerja Sel Surya 10 Wp dengan Energi Terbarukan Sumber Energi Cahaya Buatan sebagai Pengganti Sinar Matahari

Penggunaan sel surya sebagai pembangkit listrik, saat sekarang sedang dikembangkan untuk menunjang program penggunaan energi terbarukan secara luas. Hal ini bertujuan untuk menekan penggunaan energi fosil dan keselamatan lingkungan terhadap dampak polusi CO2. Untuk mengatasi persoalan tersebut maka dalam penelitian ini dirancang suatu pengembangkan energi terbarukan dengan melakukan Simulasi Kinerja Sel Surya 10 Wp dengan Sumber Energi Cahaya Buatan sebagai pengganti Sinar Matahari. Dalam sistem ini dikembangkan dua model, keluaran tegangan arus serah (DC) dan tegangan arus bolak – Balik (AC). Sel Surya 10 Wp ini kinerjanya mampu menangkap sumber energi cahaya buatan dari sebuah Lampu Bohlam 100 Watt, maka diperoleh keluaran cahaya buatan yang sesuai dengan yang diinginkan, mengikuti karakteristik sinar matahari. Pada Sel Surya 10 WP yang disinari dengan cahaya buatan ini, maka diperoleh tegangan maksimum 18 Volt DC dan tegangan maksimum 220 Volt AC. Hasil keluaran beban DC tersebut dihasilkan dari aliran batere 12 V yang telah terisi 1,25 A, maka mampu menghidupkan lampu DC 12V & 15W. Dan hasil keluaran beban AC tersebut dihasilkan dari aliran batere 12 V yang telah terisi 2A, maka mampu menghidupkan lampu bohlam AC 100W, keluaran beban AC tersebut bisa mencapai nilai maksimum hingga 500 Watt

Pengembangan Penggunaan Sistem Arus Searah sebagai Pencatu Daya pada Lampu Hemat Energi

Jenis lampu hemat energi (Compact fluorescent lamps) berbasis switch mode power supply sebagai lampu penerangan saat ini menjadi dominan karena mempunyai konsumsi daya rendah serta kuat cahaya yang tinggi. Lampu ini juga memenuhi standar SNI 04-6504-2001 sehingga dapat diterapkan dalam penggunaan lampu penerangan yang mengacu pada standar IEEE Std 446-1995 Sekalipun jenis lampu ini mempunyai kelebihan daya rendah namun jenis lampu ini mempunyai sifat kapasitip sehingga akan menimbulkan gejala harmonik, pengaruh ini akan berdampak pada kualitas penyaluran daya pada sistem distribusi jaringan listrik arus bolak Balik. Jenis lampu ini dapat bekerja dalam sistem arus bolak – Balik maupun arus searah. Penggunaan catu daya sistem arus searah diharapkan dapat menggantikan sistem catu daya pada arus bolak – Balik sehingga gejala harmonik dapat ditiadakan. Hasil penelitian dari penggunaan sistem arus searah sebagai pencatu daya lampu hemat pada lampu 18 W bekerja secara efektif pada tegangan 200 Vdc dengan arus nominal 0.06 A

Analisis Perbandingan Waktu, Biaya, dan Direct Waste Penggunaan Tulangan Konvensional, Wire Mesh, dan Floordeck pada Pekerjaan Plat Lantai

Pekerjaan plat lantai merupakan suatu elemen pada pekerjaan konstruksi gedung yang memiliki biaya besar. Hal ini dikarenakan pekerjaan plat lantai memiliki volume yang cukup besar. Analisa yang dilakukan adalah membandingkan pekerjaan plat lantai dengan menggunakan metode konvensional, menggunakan wire mesh sebagai tulangannya, dan floordeck sebagai bekisting pada pekerjaan plat lantai Proyek Apartemen Taman Melati Yogyakarta terhadap biaya, waktu, direct waste, dan metode pengerjaannya. Analisa harga satuan pekerjaan plat lantai mengacu pada harga material, dan upah tenaga kerja tahun 2016. Tujuan yang ingin dicapai dalam penulisan tugas akhir ini adalah menentukan metode mana yang tepat untuk digunakan pada suatu pekerjaan plat lantai pada Proyek Taman Melati Yogyakarta ditinjau dari perbandingan waktu, biaya, direct waste tulangannya, dan metode pengerjaannya. Analisa dilakukan dalam beberapa tahap sesuai dengan standar SAVE 2007. Setelah melakukan berbagai tahapan dalam melakukan value engineering pekerjaan plat lantai dan perhitungan mulai dari menganalisa struktur untuk mengetahui kebutuhan wire mesh dan tebal bondek yang diperlukan, menghitung luas dan volume dari pekerjaan plat dan menghitung kapasitas produksi dari metode yang digunakan kemudian didapat besarnya biaya, lamanya waktu pengerjaan, dan besarnya direct waste penulangan dari masing-masing metode yang telah dianalisa. Menggunakan metode zero-one untuk mengetahui metode mana yang lebih cocok diterapkan pada Proyek Apartemen Taman Melati. Berdasarkan metode zore-one Proyek Apartemen Taman Melati lebih efisien jika menggunakan wire mesh M9 sebagai tulangan lapis atas, wire mesh M6 ataupun tulangan konvensional D10-200 sebagai tulangan lapis bawah, dan floordeck W-1000 BMT 0,7 mm sebagai pengganti bekistingnya

Analysis of Plastic Associated Chemicals in Cinereous Vultures (Aegypius monachus).

Sammendrag Plast er en oppfinnelse av vitenskap og teknologi som er nært knyttet til våre moderne liv. Uansett hvilket aspekt vi referer til, har plast en betydelig innflytelse som gjør ting enklere, raskere og billigere. Dette har ført til en enorm mengde produksjon av plast. Produksjonsindustrien prøver kontinuerlig å fremme produksjonsteknikkene sine, øker mengden samtidig som kostnadene reduseres. Håndteringen av plastavfall har imidlertid ikke økt sammenlignet med produksjon, og dette fører til at tonnevis med plastavfall strander i miljøet, og det øker hvert år med økende produksjon. Disse plastproduktene inneholder i mange tilfeller ulike tilsetningsstoffer for å øke verdien som produkt. Disse tilsetningsstoffene ender noen ganger opp med å forårsake alvorlige toksiske effekter på organismer etter å ha blitt eksponert. Oksidativt stress, hormonforstyrrelser er noen av skadene forårsaket av denne typen tilsetningsstoffer. Disse tilsetningsstoffene er kjent som plasttilknyttede kjemikalier. Ftalater og bisfenoler er to ofte brukte slike kjemikalier, og disse lekker ut i miljøet og blir tilgjengelig for både dyrelivet og mennesker. Disse forbindelsene forurenser også organismene etter direkte inntak av plast, og mange tilfeller er rapportert om slik oppførsel. Dermed forurenser disse myknere næringsnettet og kommer seg til toppen av næringskjeden. Det er fortsatt mangel på studier angående forurensning og skade på ulike organismer forårsaket av disse myknere. Dette inkluderer fugler som vanligvis brukes som et bioovervåkingsmiddel på grunn av deres høye trofiske posisjoner og følsomhet for miljøendringene. Denne studien er rettet mot å undersøke tilstedeværelsen av ftalatmetabolitter og bisfenoler i gribbeunger i Spania utsatt for deponier. Siden plastisk forurensning av disse individene tidligere ble undersøkt, fokuserte målet med denne studien hovedsakelig på forurensning av myknere og deres korrelasjon med hverandre og biologiske faktorer. De tre biologiske faktorene som er undersøkt inkluderer individenes vekt, utviklingsdager og inkubasjonsdager. Blant de studerte ftalatmetabolittene ble fire av dem observert å ha konsentrasjoner over LOQ-nivåene (grense for kvantifisering). Disse fire metabolittene er monometylftalat (mMP), monoetylftalat (mEP), monoisobutylftalat (mIBP) og monobutylftalat (mBP) med gjennomsnittsverdier på 14,79 ± 4,65, 611,69 ± 191,73, 34,78 og 34,78 ± 37,27 ± 14,87 ng g-1 henholdsvis. Når det gjelder bisfenoler, ble bisfenol A (BPA), bisfenol S (BPS) og bisfenol Z (BPZ) funnet å ha den høyeste deteksjonsfrekvensen (DF). Ved beregning av korrelasjon mellom de biologiske faktorene og kjemikaliene ble det ikke observert noen signifikante korrelasjoner. Kjemikaliene i seg selv viste ingen korrelasjoner mellom dem da Spearmans koeffisientverdi varierte fra -0,0242 til 0,2396. Totalt sett ble tilstedeværelsen av ftalatmetabolitter og bisfenoler observert, men på grunn av mangel på studier utført på gribber eller rovfugler som helhet, ble det ganske vanskelig å sammenligne nivåene av disse to plasttilknyttede kjemikaliene og trekke en sikker konklusjon om forurensningstilstanden og potensiell risiko for eksponering i gribbene.Abstract Plastic is an invention of science and technology that is closely associated with our modern lives. No matter which aspect we refer to, plastic has a significant influence making things easier, faster and cheaper. This has led to an immense amount of production of plastics. The production industries are continuously trying to advance their production techniques, increasing the amount while decreasing the cost. The management of plastic waster however has not increased compared to production and this leads to tons of plastic waste being stranded in the environment and it is increasing every year with increasing production. These plastic products in many cases contain various additives to increase its value as a product. These additives sometimes end up causing severe toxic effects to organisms after being exposed. Oxidative stress, endocrine disruption are some of the damage caused by these types of additives. These additives are known as plastic associated chemicals. Phthalates and bisphenols are two commonly used such chemicals and these leach into the environment becoming available to the wildlife as well as humans. These compounds also contaminate the organisms after direct ingestion of plastics and many cases have been reported of such behavior. Thus these plasticizers contaminate the food web and make their ways to the top of the food chain. There is still a lack of study regarding the contamination and damage to various organisms caused by these plasticizers. This includes birds which are generally used as a biomonitoring agent because of their high trophic positions and sensitivity to the environmental change. This study is aimed at to investigate the presence of phthalate metabolites and bisphenols in cinereous vulture nestlings in Spain exposed to landfills. As the plastic contamination of these individuals were previously investigated, the aim of this study mainly focused on the contamination of the plasticizers and their correlation with each other and biological factors. The three biological factors investigated include, weight of the individuals, development days and days of incubations. Among the phthalate metabolites studied, four of them were observed to have concentrations above the LOQ (limit of quantification) levels. These four metabolites are mono methyl phthalate (mMP), mono ethyl phthalate (mEP), mono iso butyl phthalate (mIBP), and mono butyl phthalate (mBP) having mean values of 14.79 ± 4.65, 611.69 ± 191.73, 34.8 ± 16.78, and 37.27 ± 14.87 ng g-1 respectively. In case of bisphenols, bisphenol A (BPA), bisphenol S (BPS), and bisphenol Z (BPZ) were found to have the highest detection frequency (DF). While calculating correlation between the biological factors and chemicals, no significant correlations were observed. The chemicals themselves did not show any correlations between them as the Spearman’s coefficient value ranged from -0.0242 to 0.2396. Overall, the presence of phthalate metabolites and bisphenols were observed but due to lack of studies conducted upon vultures or raptors as a whole, it became quite difficult to compare the levels of these two plastic associated chemicals and draw a definite conclusion of the state of contamination and potential risks of exposures in the vultures

The Effectiveness of Ethyl Acetate Extract From Breadfrui (Artocarpus Altilis) Leaves to Inhibit Diarrhea-Causing Bacteria

Diarrhea is a health problem that commonly occurs in developing countries. Bacteria that cause diarrhea are among others Escherichia coli, Salmonella typhosa and Staphylococcus aureus. This research aimed to investigate the diameters of inhibition zones of breadfruit leaf (A. altilis) ethyl acetate extract in different concentrations against the growth of Escherichia coli, Salmonella typhosa and Staphylococcus aureus. The research applied an experimental laboratory by using a post-test control group design. This research was performed at the Bacteriology Laboratory of STIKES Nasional by using the diffusion disk method. The research showed the radical zone diameters against Escherichia coli with the concentrations of  20%, 40%, 60%, 80%, and 100%,  were 6.16 mm, 6.41 mm, 6.74 mm, 7.49 mm, and 7.79 mm, respectively.  The inhibition zones against Staphylococcus aureus were 8.15, mm 9.43 mm, 10.29, 10.38 mm and 11.42 mm, while against Salmonella typhosa were 7.94 mm, 8.87 mm, 10.15 mm, 10.26 mm, and 11.23 mm, respectively. The results of the ANOVA test showed the p-value=0.00 and the results of the LSD test revealed the differences in the inhibition effects of A. altilis leaf extract against the growth of E. coli, S. typhosa and S. aureus. This study concludes that concentration variations of Artocarpus altilis leaf ethyl acetate extract can inhibit the growth of  Escherichia coli, Staphylococcus aureus, and Salmonella typhosa.Diarrhea is a health problem that commonly occurs in developing countries. Bacteria that cause diarrhea are among others Escherichia coli, Salmonella typhosa and Staphylococcus aureus. This research aimed to investigate the diameters of inhibition zones of breadfruit leaf (A. altilis) ethyl acetate extract in different concentrations against the growth of Escherichia coli, Salmonella typhosa and Staphylococcus aureus. The research applied an experimental laboratory by using a post-test control group design. This research was performed at the Bacteriology Laboratory of STIKES Nasional by using the diffusion disk method. The research showed the radical zone diameters against Escherichia coli with the concentrations of  20%, 40%, 60%, 80%, and 100%,  were 6.16 mm, 6.41 mm, 6.74 mm, 7.49 mm, and 7.79 mm, respectively.  The inhibition zones against Staphylococcus aureus were 8.15, mm 9.43 mm, 10.29, 10.38 mm and 11.42 mm, while against Salmonella typhosa were 7.94 mm, 8.87 mm, 10.15 mm, 10.26 mm, and 11.23 mm, respectively. The results of the ANOVA test showed the p-value=0.00 and the results of the LSD test revealed the differences in the inhibition effects of A. altilis leaf extract against the growth of E. coli, S. typhosa and S. aureus. This study concludes that concentration variations of Artocarpus altilis leaf ethyl acetate extract can inhibit the growth of  Escherichia coli, Staphylococcus aureus, and Salmonella typhosa