Corrosion rate of Al-Si Alloy Reinforced with B4C Nanoparticle prepared by Powder Metallurgy Method using RSM

The current work aims to optimize the Al-Si alloy reinforced with B4C nanoparticles prepared through powder metallurgy technique. The sample was prepared with different weight percentage 0, 4 and 8; the size of the sample was 20 mm x 20mm and sintered in a furnace upto 500oC with argon gas and their by furnace cooled to room temperature. The samples were brushed to remove the slag present in it, and polished by emery paper. Then the samples were weighed in an electric balancing apparatus to measure the initial weight of the sample before dipping it into acid solution. The weight loss was measured to calibrate the corrosion rate of the samples for 9 days. Response surface methodology was designed for three factors at three levels with a response as corrosion rate. The Analysis of Variance (ANOVA) was used to identify the most influencing factor on corrosion rate. The normal probability plot, residual plot, and desirability plot demonstrates the influence of corrosion rate of the composites.

PENGARUH MODAL SENDIRI DAN MODAL PINJAMAN TERHADAP SISA HASIL USAHA (SHU) PADA KOPERASI UNIT DESA (KUD) BINA SEJAHTERA RENGAT BARAT KABUPATEN INDRAGIRI HULU

Tujuan penelitian ini adalah untuk mengetahui Modal Sendiri dan Modal Pinjaman secara simultan berpengaruh signifikan terhadap Sisa Hasil usaha (SHU), untuk mengetahui Modal Sendirisecara parsial berpengaruh signifikan terhadap Sisa Hasil usaha (SHU), untuk mengetahui Modal Pinjaman secara parsial berpengaruh signifikan terhadap Sisa Hasil usaha (SHU), di Koperasi Unit Desa Bina Sejahtera Rengat Kabupaten Indragiri Hulu. Dalam penelitian ini pola pikir yang digunakan pola pikir induktif. Analisis data menggunakan metode kuantitatif yaitu dengan asumsi klasik ,regresi linear berganda, koefisien korelasi dan determiniasi, uji F, dan uji t. Teknik pengumpulan data menggunakan interview dan studi pustaka. Berdasarkan hasil penelitian dan pembahasan maka dapat diambil kesimpulan yaitu : Dari perhitungan kuantitatif yang diperoleh dengan menggunakan rumus persamaan regresi linear berganda Y = a + b1X1 + b2X2 diperoleh Y = 21,458 + 0,32 X1 – 0,01 X2, yakni nilai koefisien konstanta (a) sebesar 21,458 hal ini berarti apabila nilai Modal Sendiri dan Modal Pinjaman sama dengan nol atau tetap, maka tingkat atau besarnya Sisa Hasil usaha (SHU) sebesar 21,458. Koefisien korelasi linear berganda (R) yaitu 0,872, artinya hubungan yang korelasi sangat kuat sekali antara Modal Sendiri dan Modal Pinjaman terhadap Sisa hasil Usaha (SHU) sebesar 0,872. Koefisien determinasi (R2) sebesar 0,761, artinya Sisa Hasil Usaha (SHU) dapat dijelaskan oleh variasi perubahan variabel independen Modal Sendiri dan Modal Pinjaman sebesar 76,1%, sedangkan sisanya 23,9% dijelaskan oleh variabel lain di luar penelitian. Berdasarkan hasil uji F diperoleh nilai Fhitung adalah 7,953 dengan tingkat signifikan 0,028. Sedangkan Ftabel pada taraf kepercayaan 95% (0,05) adalah 5,79. Pada kedua perhitungan Fhitung ˃Ftabel yaitu 7,953 ˃ 5,79. Hal ini berarti Ho ditolak dan Ha diterima, artinya secara simultan Modal Sendiri dan Modal Pinjamanberpengaruh signifikan terhadap Sisa Hasil Usaha (SHU). Berdasarkan hasil uji t diperoleh nilai thitung X1 ˃ ttabel = 2,635 < 2,44691 sehingga Ho ditolak dan Ha diterima, yang berarti variabel independen Modal Sendirisecara parsial berpengaruh signifikan terhadap Sisa Hasil Usaha (SHU). Selanjutnya nilai thitung X2 > ttabel = -1,288 > -2,44691 sehingga Ho ditolak dan Ha diterima, yang berarti variabel independen Modal Pinjaman secara parsial berpengaruh signifikan terhadap variabel Sisa Hasil Usaha (SHU). Berdasarkan hasil Uji Klasik diperoleh nilai Uji Multikolinieritas bahwa nilai tolerance dari kedua variabel independen lebih dari 0,1 yaitu VIF kurang dari 10 yaitu 1,328, maka dapat disimpulkan bahwa dalam model regresi tidak terjadi masalah multikolinieritas. Selanjutnya uji heteroskedastisitas diketahui bahwa titik-titik menyebar dengan pola yang tidak jelas diatas dan dibawah angka 0 pada sumbu Sisa Hasil Usaha (SHU) maka pada hasil ini tidak terjadi masalah heteroskedastisitas. Dan yang terakhir uji normalitas pada tampilan grafik histogram, didapatkan garis kurva normal, berarti data yang diteliti diatas berdistribusi normal. Demikian juga dari normal probability plot, menunjukan berdistribusi normal karena garis (titik-titik) mengikuti garis diagonal

Penentuan Kinerja Organisasi Pemerintah Daerah di Kabupaten Musi Banyuasin, Provinsi Sumatera Selatan

This study aims to determine and analyze the influence of Determination of Organizational Performance of Regional Devices of the Government of Musi Banyuasin Regency in South Sumatra Province The data in this study were collected using the method of observation and survey through interviews and with the help of research instruments in the form of questionnaires totaling 144 examinations which were distributed directly to 52 local government organizations in Musi Banyuasin Regency, which were addressed directly to regional heads. work units, secretaries and section heads who work for local government organizations. Data in this study will be analyzed using multiple linear regression with the help of SPSS software version 24.0. To test the validity and reliability of research instruments used the Correlation Item-Total Correction and Cronvach's Alpha. In addition, data normalization is also tested using the normal probability plot. The results of this study indicate that of these four variables; Clarity of budget targets, internal control systems, good governance, and professionalism have a positive and significant effect on organizational performance either partially or simultaneously.

Template Recycling and Reuse in MCM-41 Synthesis: Statistical Study

The recycle and reuse of template in MCM-41 synthesis were analysed using 23 full factorial design in order to study the effect of the template extraction parameters on the mass of MCM-41 powder produced. Four consecutive MCM-41 synthesis cycles utilizing the recycled template were studied with three factors that are ethanol fraction (A), amount of ion exchange agent (B) and the type of ion exchange agent (C). The significant effects contributed by the factors A, B and C and their interactions were identified through the half-normal probability plot and normal probability plot of the residuals. F-test and t-test were carried out to test the contribution of regression coefficients for synthesis cycles of MCM-41 synthesis models. AB interaction showed that larger mass of MCM-41 powder was obtained at high ethanol volume fraction and high quantity of ion exchange agent when either type of ion exchange agent was used.

Use of Ligand-based Iron Complexes for Phenol Degradation by Fenton Modified Process

The efficiency of phenol degradation by the iron complexes ([Fe(TBMA)Cl₃∙3H₂O] and [Fe(terpy)Cl₂]) is compared with that of the Fenton reaction. The results show that although the Fenton reaction efficiently oxidizes phenol at low pH’s, the Fenton modified reagents (iron complexes/H₂O₂) effectively oxidize phenol at neutral pH. Besides, the factorial designing study is performed by considering three independent variables: (i) [Fe] (<em>A</em>), (ii) pH (<em>B</em>), and (iii) [H₂O₂] (<em>C</em>). For the Fenton reaction, the normal probability plot reveals that two factors, such as concentration of Fe²⁺ and interaction{[H₂O₂]∙pH} have considerable influence on the phenol oxidation; in the normal probability plot of the complexes, factors C (concentration of H₂O₂) and AC {[Fe]∙[H₂O₂]} have an effect on the oxidation of the phenol by [Fe(terpy)Cl₂]/H₂O₂, while for [Fe(TBMA)Cl₃∙3H₂O], factors B and AC significantly influence the degradation. Of both iron complexes, [Fe(TBMA)Cl₃∙3H₂O]/H₂O₂ is an excellent oxidant, showing a good response at pH 7.0.

Why direct and post-refinement determinations of absolute structure may give different results

Direct determination of the Flack parameter as part of the structure refinement procedure usually gives different, though similar, values to post-refinement methods. The source of this discrepancy has been probed by analysing a range of data sets taken from the recent literature. Most significantly, it was observed that the directly refined Flack (x) parameter and its standard uncertainty are usually not much influenced by changes in the refinement weighting schemes, but if they are then there are probably problems with the data or model. Post-refinement analyses give Flack parameters strongly influenced by the choice of weights. Weights derived from those used in the main least squares lead to post-refinement estimates of the Flack parameters and their standard uncertainties very similar to those obtained by direct refinement. Weights derived from the variances of the observed structure amplitudes are more appropriate and often yield post-refinement Flack parameters similar to those from direct refinement, but always with lower standard uncertainties. Substantial disagreement between direct and post-refinement determinations are strongly indicative of problems with the data, which may be difficult to identify. Examples drawn from 28 structure determinations are provided showing a range of different underlying problems. It seems likely that post-refinement methods taking into account the slope of the normal probability plot are currently the most robust estimators of absolute structure and should be reported along with the directly refined values.

OPTIMASI PRODUKSI GAULTHERIN DARI GANDAPURA DENGAN TEKNOLOGI MIXED-DrYING EXTrACTION

Tujuan studi ini adalah menentukan optimasi produksi gaultherin dari gandapura melalui teknik inaktivasi enzim gaultherase dengan teknologi mixed-drying extraction. Kegiatan riset meliputi studi produktifitas gaultherin dan optimisasi parameter-parameter proses. Upaya yang dapat meningkatkan produktifitas gaultherin diantaranya pengaruh penambahan drying agent (magnesium sulfat, sodium sulfat, kalsium klorida, dan kalsium sulfat). Optimisasi dilakukan menggunakan faktorial design 2n. Penentuan variabel berpengaruh dengan menggunakan normal probability plot, setelah dilakukan perhitungan main efek dan perhitungan interaksi. Selama riset, diukur kandungan gaultherin, metil salisilat, asam salisilat menggunakan spektrofotometer maupun HPLC-MS. Hasil riset menunjukkan bahwa meningkatnya konsentrasi drying agent maupun etanol menyebabkan perolehan gaultherin semakin besar, terutama dengan penambahan kalsium klorida. Hasil telaah menyatakan bahwa variabel proses mixed-drying extraction untuk inaktivasi enzim gaultherase yang paling berpengaruh adalah pH dan konsentrasi etanol. Semakin besar pH ekstraksi, akan meningkatkan perolehan senyawa aktif gaultherin. Kondisi optimum mixed-drying extraction untuk inaktivasi enzim tercapai pada pH 8 dengan kadar senyawa aktif gaultherin sebesar 14,46%. Semakin besar konsentrasi pelarut, gaultherin yang terekstrak semakin meningkat. Produksi gaultherin secara maksimum tercapai pada konsentrasi etanol 90% dengan perolehan senyawa aktif sebesar 13,10%. This study purposed the optimization of gaultherin production from “gandapura” by inactivating the gaultherase enzyme, including gaultherin productivity and process parameters. This research applied the combination processes of extraction-dryer, simultanously. The productivity of gaultherin was improved by adding the drying agent, such as magnesium sulfate, sodium sulfate, calcium chloride, and calcium sulfate. The optimization was conducted using a factorial design 2n. Dependent variables determined by calculating the main effects and interactions, following by the application of probability plots. During the research, the content of gaultherin, methyl salicylate, salicylic acid were measured by using a spectrophotometer and HPLC-MS. The results shows that the higher concentration of drying agent (especially calcium chloride) and ethanol, increased the content of gaultherin. However, the most influenced factor to this conducted process was pH, regarding to the concentration of ethanol. During extraction, the higher the pH, increased the active compound of gaultherin. The optimum condition of enzyme inactivation was found at pH 8 with the content of gaultherin at 14.46%. The higher the solvent concentration of ethanol, the higher content of gaultherin can be extracted. The maximum process condition regarding to ethanol concentration found at 90% with active compound concentration at 13.10%.

Research on the Iterative Stopping Criterion Based on Linear Turbo Equalization

Although turbo equalization has superior performance, the data processing delay produced by large iterations has become its major drawback for real-time situations. Based on the MMSE criterion, the normal-probability-plot (NPP) of linear equalizer’s extrinsic information is studied in this paper, with the conclusion of the extrinsic information’s approximate Gaussian distribution obtained. In various conditions, the iterative number can be controlled dynamically based on the extrinsic information statistics. The simulation results approves that the technique is able to make delay dwindle largely with small performance degradation.

EPILEPTIC SEIZURE DETECTION IN EEG SIGNALS USING MULTIFRACTAL ANALYSIS AND WAVELET TRANSFORM

This paper explores the three different methods to explicitly recognize the healthy and epileptic EEG signals: Modified, Improved, and Advanced forms of Generalized Fractal Dimensions (GFD). The newly proposed scheme is based on GFD and the discrete wavelet transform (DWT) for analyzing the EEG signals. First EEG signals are decomposed into approximation and detail coefficients using DWT and then GFD values of the original EEGs, approximation and detail coefficients are computed. Significant differences are observed among the GFD values of the healthy and epileptic EEGs allowing us to classify seizures with high accuracy. It is shown that the classification rate is very less accurate without DWT as a preprocessing step. The proposed idea is illustrated through the graphical and statistical tools. The EEG data is further tested for linearity by using normal probability plot and we proved that epileptic EEG had significant nonlinearity whereas healthy EEG distributed normally and similar to Gaussian linear process. Therefore, we conclude that the GFD and the wavelet decomposition through DWT are the strong indicators of the state of illness of epileptic patients.