Texture evolution in biocompatible Mg-Y-Re alloy after friction stir processing

The presented study deals with the investigation of biocompatible WE 43 Mg-based alloy processed via the combination of rotary swaging (RS) and friction stir processing (FSP) at three different rotational speeds of 400 RPM, 800 RPM, and 1200 RPM. The structure observations primarily focused on texture development and characterizations of grain sizes and grain boundaries. The results showed that swaging plus processing at 400 RPM and 1200 RPM lead to substantial recrystallization and grain refinement. The fractions of low angle grain boundaries within the 400 RPM and 1200 RPM samples were approximately 11%, while for the 800 RPM sample exhibiting secondary recrystallization it was about 22%. The grains were also the finest in the 1200 RPM sample (average grain diameter of 1.8 mu m). The processed structures exhibited a slight tendency to form the {10-10} preferential fiber texture (especially the 800 RPM sample). Tensile testing showed the FSP to have positive influence on the ultimate tensile stress, as well as ductility of all the samples; the mechanical properties improved with increasing FSP rate.Web of Science911art. no. 118

Temperature distribution in the force-driven poiseuille gas flow by molecular dynamics

This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.The thermal behavior of the force-driven compressible Poiseuille gas flow is studied by molecular dynamics (MD) simulation method. This type of flow situation occurs in the cooling system of MEMS/NEMS devices and hence the properties of Poiseuille gas flow become significant, especially the thermal behavior. The peculiar behavior of the force-driven Poiseuille gas flow, local minimum at the center in the temperature profile, is investigated in detail. Emphasis is placed on variations of the temperature distribution for different Knudsen numbers. Previously, the central temperature minimum and other flow peculiarities have been described by a non-classical non-Fourier theory based on nonlinear coupled constitutive relations. The main goal of this study is to investigate the thermal behavior of the force-driven Poiseuille gas flow using molecular dynamics simulations and to compare the results with that of non-classical non-Fourier theory. The MD results in general show agreement with the data from the non-classical hydrodynamic theory, which confirms the validity of MD method in analyzing the micro/nano gas flows including thermal behaviors

Knock phenomenon analysis on a diesel-CNG dual fuel engine using experimental fuel ratio

Knock avoidance is crucial to establish a proper Diesel-CNG Dual Fuel (DDF) engine. The causes of this phenomenon are still vague due to the lack of knock detection and characterization methods available. This study presents a knock characterization technique using a statistical analysis based on engine block vibration signal. Several experiments were conducted on a 2.5-litre converted DDF engine running at a constant engine speed between 1400 rpm and 3000 rpm with several diesel to CNG fuel ratio. This study found that when the diesel to CNG fuel ratio reached 70:30 at 1800 rpm to 3000 rpm, and 60:40 at 1400 rpm and 1600 rpm, engine knock was detected. A knock index was calculated from the vibration signal using Band-pass, Rectify, Integrate, and Compare (BRIC) method to determine knock intensity for each engine cycle. A three-sigma rule was applied to determine the threshold level of knock occurrence at the tested engine speeds. The knock thresholds at 1400 rpm, 1600 rpm, 1800 rpm, 2000 rpm, 2200 rpm, 2400 rpm, 2600 rpm, 2800 rpm, and 3000 rpm were found to have a knock index of 3.72, 3.49, 3.21, 2.71, 2.27, 1.80, 2.02, 1.80, and 1.73 respectively. Using a 5% knock cycle occurrence within the third and sixth standard deviation as a deciding criteria, a knock quality level was categorised as a vague, light, medium, and heavy knock. The analysed result shows that a severe knock occurred due to a sudden transition between a low and high knock intensity in a consecutive engine cycle, which yields a non-periodic mechanical shock. The calculated coefficient of variation of the knock index (COVKI) shows that the severe knock occurred when the COVKI is 0.30 and above. It suggests that the knock phenomenon on a DDF engine occurs due to an abrupt heat release rate during the mixing-controlled combustion phase and micro-explosion during the late combustion phase

Perbedaan Kadar Alanine Aminotransferase (Alt) Dalam Serum Dari Darah Yang Disentrifugasi Pada Kecepatan 3000 Rpm Selama 5 Menit Dan 4400 Rpm Selama 3 Menit

Background : Laboratory tests for liver and heart are emergency, so the examination must be carried out quickly including ALT examination. One way is by reducing the time of centrifugation without reducing the quality of serum. Reducing the time of centrifugation to 3 minutes at 4400 rpm is expected to provide the same results by centrifuging for 5 minutes at 3000 rpm. So that, the duration of ALT examination can be faster, reduces Turnaround Time (TAT) or patient waiting time, and saves electrical energy which can reduce the variable cost. Method : This research was a pre-experimental study with Static Group Comparison research design. The examination used IFCC without pyridoxal method. The subjects of research were 22 people. Samples were serum of blood that were frozen for 30 minutes then centrifuged at 3000 rpm for 5 minutes and 4400 rpm for 3 minutes. Samples were examined using A15 biosystem instrument. Data were analyzed by Wilcoxon test. Result : The results showed mean value of ALT centrifuged at 3000 rpm for 5 minutes was 16,32 U/L and 4400 rpm for 3 minutes was 16,50 U/L. Based on Wilcoxon test, there was no difference in ALT level from centrifuged blood samples at 3000 rpm for 5 minutes and 4400 rpm for 3 minutes, p-value (sig) = 0.676 with a significant level (α = 0.05) then p-value (sig. 2 tailed) > 0.025. Conclusion : There was no difference in ALT level in serum from blood that was centrifuged at 3000 rpm for 5 minutes and 4400 rpm for 3 minutes

Return to return point memory

We describe a new class of systems exhibiting return point memory (RPM) that are different from those discussed before in the context of ferromagnets. We show numerically that one dimensional random Ising antiferromagnets have RPM, when configurations evolve from a large field. However, RPM is violated when started from some stable configurations at finite field unlike in the ferromagnetic case. This implies that the standard approach to understanding ferromagnetic RPM systems will fail for this case. We also demonstrate RPM with a set of variables that keep track of spin flips at each site. Conventional RPM for the spin configuration is a projection of this result, suggesting that spin flip variables might be a more fundamental representation of the dynamics. We also present a mapping that embeds the antiferromagnetic chain in a two dimensional ferromagnetic model, and prove RPM for spin exchange dynamics in the interior of the chain with this mapping

Prototype RPM Digital Meter Berbasis Mikrokontroler ATMega 8 Untuk Sepeda Motor Dengan Penampil Seven Segment

Proyek Akhir ini dimaksudkan untuk mendapatkan suatu alat ukur Prototype RPM Digital Berbasis Mikrokontroler ATMega 8 Dengan Penampil Seven Segment yang mampu mengukur besar kecilnya putaran RPM sepeda motor. Alat ini diharapkan dapat mempermudah pekerjaan dalam mengukur putaran RPM sepeda motor, sehingga dapat menyelesaikan permasalahan kepresisian pengukuran RPM sepeda motor. Alat ini dibuat menggunakan konversi tegangan yang diolah oleh mikrokontroler Atmega8 dan ditampilkan menggunakan seven segment. Alat ini dikembangkan dalam beberapa tahapan yaitu, (1) Identifikasi Kebutuhan, (2) Analisis Kebutuhan, (3) Perancangan Sistem, (4) Perancangan Perangkat Keras yang meliputi : Mikrokontroler ATmega 8 dan seven segment, (5) Perancangan Perangkat Lunak menggunakan CodeVision AVR, (6) Teknik Pengoperasian, dan (7) Pengujian Alat. Prototype ini bekerja dengan menggunakan masukan berupa pulsa (clock) yang berasal dari putaran langsam sepeda motor, yang diolah oleh mikrokontroler Atmega 8 dan hasil pengolahan tersebut ditampilkan ke seven segment, adapun hardware dalam alat ini berupa mikrokontroler Atmega 8 sebagai pengkonversi pulsa (clock) ke digital, seven segment sebagai penampil hasil pengolahan data. Unjuk kerja “Prototype RPM Digital berbasis Mikrokontroler Atmega 8 dengan penampil Seven Segment”, secara keseluruhan telah sesuai dengan fungsi yang ditetapkan, yaitu saat sepeda motor dihidupkan maka seven segment akan menampilkan input yang terdeteksi. Dari hasil pengujian RPM prototype dengan RPM standar telah didapat perbandingan error rata-rata sebesar 3%

High cycling cadence reduces carbohydrate oxidation at given low intensity metabolic rate

Cycling cadence (RPM)-related differences in blood lactate concentration (BLC) increase with increasing exercise intensity, whilst corresponding divergences in oxygen uptake (VO2) and carbon dioxde production (VCO2) decrease. We tested the hypothesis, that a higher RPM reduces the fraction (%) of the VO2 used for carbohydrate oxidation (relCHO) at a given BLC. Eight males (23.9 +/- 1.6 yrs; 177 +/- 3 cm; 70.3 +/- 3.4 kg) performed incremental load tests at 50 and 100 RPM. BLC, VO2 and VCO2 were measured. At respiratory exchange ratios (RER) <1, relCHO were calculated and the constant determining 50% relCHO (kCHO) was approximated as a function of the BLC. At submaximal workload, VO2 and RER were lower (p<0.001) at 50 than at 100 RPM. No differences were observed in VO2peak (3.96 +/- 0.22 vs. 4.00 +/ 0.25 l min-1) and RERpeak (1.18 +/- 0.02 vs. 1.15 +/- 0.02). BLC was lower (p<0.001) at 50 than at 100 RPM irrespective of cycling intensity. At 50 RPM, kCHO (4.2 +/- 1.4 (mmol l-1)3) was lower (p<0.05) than at 100 RPM (5.9 +/- 1.9 (mmol l-1)3). This difference in kCHO reflects a reduced CHO oxidation at a given BLC at 100 than at 50 RPM. At a low exercise intensity, a higher cycling cadence can substantially reduce the reliance on CHO at a given metabolic rate and/or BLC

PENGOLAHAN TSS DAN COD DALAM AIR LIMBAH DOMESTIK RUMAH MAKAN MENGGUNAKAN NANO BIOKOAGULAN DARI BIJI ASAM JAWA (TAMARINDUS INDICA)

Pemanfaatan koagulan kimia dalam pengolahan air limbah domestik khususnya rumah makan mulai tergantikan dengan koagulan alami khususnya dari biji asam jawa (Tamarindus indica). Biji asam jawa mengandung beberapa komposisi yang dapat digunakan sebagai koagulan dan zat aktif yang terkandung adalah tannin, saponin yang berfungsi membunuh mikroba dan membentuk larutan koloidal dan protein yang bekerja sebagai koagulan. Penelitian ini dilakukan untuk mengetahui pengaruh koagulan biji asam jawa pada variasi dosis dan variasi pengadukan dalam menurunkan kadar Total Suspended Solid dan Chemical Oxygen Demand air limbah domestik rumah makan. Penggunaan koagulan biji asam jawa dalam proses jartest untuk a) mengetahui dosis optimal koagulan, b) mengetahui kecepatan optimal pengadukan dan c) mengetahui hubungan antara pemberian dosis koagulan terhadap penurunan Total Suspended Solid dan Chemical Oxygen Demand. Sampel yang digunakan berasal dari air limbah Pizza Hut, Jl. Majapahit, Semarang. Penggunaan dosis koagulan 150 mg/l; 200 mg/l; 250 mg/l; 300 mg/l dengan kecepatan pengadukan cepat 100 rpm; 125 rpm; 150 rpm selama 2 menit, dilanjutkan pengadukan lambat 45 rpm selama 15 menit dan pengendapan selama 30 menit. Hasil penelitian dosis optimal penurunan Total Suspended Solid pengolahan I sebesar 152 mg/l dengan efisiensi 29,3% pada kecepatan pengadukan 150 rpm. Dosis optimal penurunan Total Suspended Solid pengolahan II sebesar 155 mg/l dengan efisiensi 24 % pada kecepatan pengadukan 125 rpm. Dosis optimal penurunan Total Suspended Solid pengolahan III sebesar 111 mg/l dengan efisiensi 41 % pada kecepatan pengadukan 150 rpm. Hasil penelitian dosis optimal penurunan Chemical Oxygen Demand pengolahan I sebesar 310 mg/l dengan efisiensi 30,6 % pada kecepatan pengadukan 150 rpm. Dosis optimal penurunan Chemical Oxygen Demand pengolahan II sebesar 307 mg/l dengan efisiensi 22,3 % pada kecepatan pengadukan 125 rpm. Dosis optimal penurunan Chemical Oxygen Demand pengolahan III sebesar 183 mg/l dengan efisiensi 36,9 % pada kecepatan 150 rpm. Kata Kunci: biji asam jawa, koagulan, chemical oxygen demand, dosis optimal, jartest, limbah domestik, total suspended soli

Brief report : the level and nature of autistic intelligence revisited

Owing to higher performance on the Raven’s Progressive Matrices (RPM) than on the Wechsler Intelligence Scales (WIS), it has recently been argued that intelligence is underestimated in autism. This study examined RPM and WIS IQs in 48 individuals with autism, a mixed clinical (n = 28) and a neurotypical (n = 25) control group. Average RPM IQ was higher than WIS IQ only in the autism group, albeit to a much lesser degree than previously reported and only for individuals with WIS IQs <85. Consequently, and given the importance of reliable multidimensional IQ estimates in autism, the WIS are recommended as first choice IQ measure in high functioning individuals. Additional testing with the RPM might be required in the lower end of the spectrum