192,480 research outputs found
COVER PIN No.16/Th.IX, April 2016
No full textFile ini berisi :1. Cover2. Susunan Redaksi3. Kata Penganta
Free-convection condensation on single horizontal pin-fin tubes
No full textPhDNew experimental data are reported for free-convection condensation of ethylene
glycol and R-113 on three-dimensional pin-fin tubes. Effects of pin geometry and tube
thermal conductivity (for copper, brass and bronze giving a mean range of 400, 120 and
80 W/m K over the range of temperature of interest) were investigated. All tests were
performed at near atmospheric pressure with downward flowing vapour at low velocity.
Heat-transfer enhancement was found to be approximately twice the corresponding
active surface area of the tubes, i.e. the surface area of the parts of the tube and pin
surface not covered by condensate retained by surface tension. For ethylene glycol, the
best performing pin-fin tube gave a heat-transfer enhancement of 5.8, about 24 %
higher than the ‘equivalent’ two-dimensional integral-fin tube (i.e. with the same finroot
diameter, longitudinal fin spacing and thickness and fin height). For R-113, the
best enhancement was 5.9, about 10 % higher than the equivalent integral-fin tube.
For both fluids tested, vapour-side, heat-transfer enhancement was found to increase
with decreasing circumferential pin spacing and increasing pin height. Circumferential
pin thickness had little effect on heat-transfer enhancement. Effects of tube thermal
conductivity were found to be more significant for ethylene glycol than R-113.
Retention angle measurements were made under static conditions (without
condensation) and were found to be larger than for equivalent integral-fin tubes. An
expression for condensate retention angle on pin-fin tubes was proposed and found to
agree with the measured retention angles to ±15%.
A semi-empirical model for condensation heat transfer on horizontal pin-fin tubes has
been developed which accounts for the combined effect of gravity and surface tension.
The model predicts the majority of available data to ±20 %
Risks of Offline Verify PIN on Contactless Cards
No full textContactless card payments are being introduced around the world al- lowing customers to use a card to pay for small purchases by simply placing the card onto the Point of Sale terminal. Contactless transactions do not require veri- fication of the cardholder’s PIN. However our research has found the redundant verify PIN functionality is present on the most commonly issued contactless credit and debit cards currently in circulation in the UK. This paper presents a plausible attack scenario which exploits contactless verify PIN to give unlimited attempts to guess the cardholder’s PIN without their knowledge. It also gives experimental data to demonstrate the practical viability of the attack as well as references to support our argument that contactless verify PIN is redundant functionality which compromises the security of payment cards and the cardholder
Pin & Mix: When Pins Become Interaction Components...
No full textThis paper introduces a study into the realization of physical interaction components, based on a technology for providing network connectivity and power to small objects via a layered surface. Small pin-like components can be activated and networked by attaching them to the same, augmented surface, and can be used to dynamically create an interlinked set of atomic interaction components. The physical connection becomes thus also a digital link between components. To demonstrate our proposed platform, we have built atomic interface components in the form of dials and multicolour lights that are activated and integrated in a network by simply pushing their pin connectors in an augmented surface. They allow to pick and mix colours using the red, green, and blue primaries, as a physical alternative for the traditional WIMP colour mixer tools
[Texas Motorcycle Club Pin]
No full textDecorative pin from the Texas Motorcycle Club. The pin features a maroon background with a centered upside down triangle, with a Texas flag in the center. Text at the top reads "Texas" with "M" on the lower left, and "C" on the lower right
STUDI PEMBUATAN SPESIMEN MINI UJI TARIK DENGAN TEKNIK BLANKING/PUNCHING
No full textABSTRAK STUDI PEMBUATAN SPESIMEN MINI UJI TARIK DENGAN TEKNIK BLANKING/PUNCHING. Telah dilakukan studi pembuatan spesimen mini uji tarik dengan teknik blanking/punching. Tujuan dari studi ini adalah untuk memperoleh informasi-informasi teknis yang akan digunakan untuk merancang rangkaian dies spesimen mini uji tarik. Uji tarik dengan spesimen mini merupakan bagian dari program investigasi efek radiasi terhadap material komponen reaktor, di Instalasi Radiometalurgi. Metoda yang dilakukan dalam pengkajian ini berupa kombinasi studi literatur dan peninjauan di lapangan. Informasi-informasi teknis tersebut mencakup proses blanking, bentuk dan dimensi dari spesimen mini uji tarik, daya blanking (kapasitas mesin preSS), material, serta suaian (clearance) antara punch dan dies. Spesimen mini uji tarik jenis sheet type spesimen dengan pin loaded dapat dijadikan kandidat (Gambar-1, [c]). Daya blanking merupakan perkalian shear strength material yang dipotong (0,7 x UTS, Ultimate Tensile Strength) dengan luasan permukaan potong (tebal x keliling dari bagian yang dipotong). Material dapat berupa logam keras seperti baja A533 B (UTS 656 MPa), baja nirkarat 316 sebesar (UTS 593 MPa) dan Zircaloy-4 (UTS 473 MPa) dan paduan Aluminium seperti Al-6061 (T6, UTS 311 MPa) dan Al-5052 (H38, UTS 335 MPa). Suaian antara punch dan dies berpengaruh terhadap kepresisian hasil blanking. Besar suaian bervariasi dari 1% s/d 10% dari tebal lembaran benda kerja. Suaian dari material yang lunak lebih kecil dari material yang keras. Pemolesan terhadap permukaan spesimen mini uji tarik dapat dilakukan untuk menghilangkan burrs setelah proses blanking. Disarankan untuk penggunaan satu rangkaian dies dengan beberapa material uji (baja A533 B, baja nirkarat 316, Zircaloy-4, Al-5052 dan Al-6061), dapat menggunakan SS-316 sebagai asumsi material dan tebal 1 mm, serta suaian punch dan dies sebesar 7%. Kata kunci: blanking, spesimen mini, uji tari
[Texas Motorcycle Club 10th Anniversary Pin]
No full textDecorative pin from the Texas Motorcycle Club commemorating their 10th anniversary. The pin features a maroon background with a upside down triangle, with a Texas flag in the upper center. Text above reads "Texas" with "M" on the lower left, and "C" on the lower right. In an encompassing maroon ring are the words "10th Anniversary"
An optimization study of a multiple-row pin-vented brake disc to promote brake cooling using computational fluid dynamics
No full textBrake disc cooling is an important area of research for high-performance brake disc manufacturers, users as well as academia. In high-demand braking applications, vented discs are increasingly being used as these are considered to have high heat-dissipating characteristics. The cooling efficiency of ventilated brakes depend on three key characteristics: the mass flowrate through the disc, i.e. the pumping efficiency of the rotor, the average heat transfer coefficient on the surface of the disc, and the wetted area of the rotor. Recent research has shown that the pin-vented discs have high heat transfer rates because of an increase in turbulence which results in a higher heat transfer coefficient. The pin-vented discs also have a higher resistance to thermal deformation owing to the more even distribution of material, resulting in lower thermal stress build-up within the rotor. The pin-vented discs in general have multiple rows of pins. In this paper an optimal configuration of various rows has been found for the maximum heat transfer rate. It has also been found that the ratio of wetted area of the disc to the frontal area of pins defines the heat transfer rate from the disc uniquely and can be used as a design parameter for the optimal design of a brake dis
PIN generation using EEG : a stability study
No full textIn a previous study, it has been shown that brain activity, i.e.
electroencephalogram (EEG) signals, can be used to generate personal
identification number (PIN). The method was based on brain–computer
interface (BCI) technology using a P300-based BCI approach and showed that
a single-channel EEG was sufficient to generate PIN without any error for
three subjects. The advantage of this method is obviously its better fraud
resistance compared to conventional methods of PIN generation such as
entering the numbers using a keypad. Here, we investigate the stability of these
EEG signals when used with a neural network classifier, i.e. to investigate the
changes in the performance of the method over time. Our results, based on
recording conducted over a period of three months, indicate that a single
channel is no longer sufficient and a multiple electrode configuration is
necessary to maintain acceptable performances. Alternatively, a recording
session to retrain the neural network classifier can be conducted on shorter
intervals, though practically this might not be viable
UJI FUNGSI ALAT ANALISIS KARBON – SULFUR MERK LECO CS-744
No full textABSTRAK–Telah dilakukan uji fungsi alat analisis karbon–sulfur merk Leco CS-744. Alat analisis karbon - sulfur Leco CS-74 merupakan alat baru. Uji fungsi dilakukan untuk mengetahui kinerja dan kemampuan alat analisis karbon-sulfur meliputi personal computer (PC), timbangan analitik, regulator gas dan alat CS-744. Bahan yang digunakan untuk melakukan uji fungsi adalah standar karbon dalam baja dengan kadar C 0,177 ± 0,003% dan S 0,005 ± 0,0005% ; C 0,668 ± 0,008% dan S 0,0108 ± 0,0004% serta C 0,811 ± 0,007% dan S 0,0108 ± 0,0004%. Bahan standar yang digunakan buatan Leco Corporation dan mengacu pada SRM dengan sertifikat yang tertelusur. Dari hasil uji fungsi diperoleh hasil neraca analitik, regulator gas, dan alat CS-744 berfungsi sesuai spesifikasi. Hasil analisis standar diperoleh berturut-turut dengan rata-rata dan standar deviasi : C 0,177 ± 0,0002 % dan S 0,0055 ± 0,0002% ; C 0,669 ± 0,0014% dan S 0,0108 ± 0,0003% serta C 0,810 ± 0,0017% dan S 0,0064 ± 0,0005%. Ini menunjukkan bahwa alat analisis karbon – sulfur merk Leco CS-744 berfungsi dengan baik sesuai dengan jangkau ukur yang diijinkan. Kata Kunci–Uji fungsi , Leco CS-744, Inframerah ABSTRACT-Instrument functional test on carbon–sulfur analyzer LECO CS-744 has been done. This is a new instrument. Functional test has been done to explore its performance and capability comprehend to personal computer (PC), analytical balanced, gas regulator and CS-744 instrument. Material that used in functional test was carbon standard in iron with several concentration. Three variant concentration carbon standard were used, C at 0.177 ± 0.003% and S at 0.005 ± 0.0005%; C at 0.668 ± 0.008% and S at 0.0108 ± 0.0004% and C at 0.811 ± 0.007% and S at 0.0108 ± 0.0004%. Standard material made by LECO Corporation and adopted the CRM with traceable certificate. The results show analytical balance, gas regulator and CS-744 instrument works as its specified. The results on standard material for each variant were C at 0,177 ± 0,0002 % and S at 0,0055 ± 0,0002% ; C at 0,669 ± 0,0014% and S at 0,0108 ± 0,0003% and C at 0,810 ± 0,0017% and S at 0,0064 ± 0,0005%. These results showed the instrument carbon-sulfur analyzer LECO CS-744 worked properly at its allowable measurement range. Keywords–Functional test, Leco CS-744, infrare
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