Basic theory and experimental approach to characterize flow and fracture properties of fine powder bulk body

This dissertation comprised two parts, which were Part I for the development of a method to characterize the fine powder flow at ambient temperature and Part II for the application of the method in fine powder aeration at elevated temperature.;The analysis conducted on fine powder aeration in Part I was based on the theory of homogeneously-aerated-expanded (HAE) emulsion phase, which viewed a system of aerated fine powders as a quasi-solid single phase.;The original aeration data from an aeration experiment (gas velocity, pressure drop, and bed height) were transformed into the new variables specifically defined for aerated fine powder (powder strain and powder tensile stress). The plots of powder tensile stress against powder strain indicated a consistent tendency for all experimental data. Based on this fact, a parameter called elastic deformation coefficient (Y) was determined from those plots and defined as the characterization parameter for fine powder aeration behaviors.;The point of intrinsic Umb could be accurately determined as the point of sudden change of Y value on the plot of Y against powder strain. These Y values also provided a quantitative tool to compare the aeration quality of several different systems of fine powders.;In Part II, to study the effect of temperature on aeration quality, the Y method was applied on aerated FCC catalyst at temperatures ranged from 26°C to 600°C.;At ambient temperature, the aeration quality of FCC catalyst was very poor and it was indicated by an initially high Y which kept increasing through the whole range of strain until the maximum expansion. In contrast to that, at elevated temperature, a region of constant Y was observed in the plot of Y against strain. This fact indicated that at high temperature, an ideal HAE emulsion phase could be maintained over a wide range of strain before the first fractures occurred. These results showed that Y value served as a general characterization parameter that could be applied consistently at both ambient and elevated temperature

Preparation and Characterization of Glutaraldehyde-Crosslinked Kappa Carrageenan Hydrogel

Glutaraldehyde-crosslinked kappa carrageenan hydrogel was prepared using glutaraldehyde (GA) as the crosslinking agent. Kappa carrageenan film obtained from extraction of Kappaphycus alvarezii seaweed was immersed in GA solution (1 - 5 wt%) for 2 min and then cured at 110oC for 25 min. The obtained crosslinked film was washed and soaked in the ethanol to remove the unreacted GA. The obtained film was air dried at room temperature to a constant weight. The infrared spectra, thermal analysis, and the value of swelling degree of obtained hydrogel showed that kappa carrageenan was able to be crosslinked using GA by film immersion and high temperature curing method without catalyst presence. GA concentration less than 0.027 g GA/g polymer was not able to crosslink hydroxyls group of carrageenan. The swelling degree in water media decreased up to 60% with increasing GA concentration from 3% to 5%. The kappa carrageenan hydrogel was found to be pH sensitive

Mekanisme Proses Tahap Ekstraksi Karagenan Dari Eucheuma cottonii Menggunakan Pelarut Alkali (The Mechanism of Carrageenan Extraction from Eucheuma cottonii Using Alkaline Solvent)

Carrageenan recovery process was developed for Eucheuma cottonii by investigating the effects of distilled water, KOH (0.1-0.5 N) and NaOH (0.1-1.0 N) as the solvent on carrageenan yield and gel properties. Extraction process was carried out with a constant ratio of seaweed weight to solvent volume (1: 50; g/mL) at 80oC.  A certain amount of the liquid sample was withdrawn at regular interval time for analysis. Filtrate was separated from residue by pouring ethanol. The precipitated carrageenans were collected and oven dried at 50-60oC to a constant weight. The extraction product was found to have virtually identical infrared spectra to the reference samples of kappa-carrageenan. Distilled water was the most efficient solvent with regard to yield but certainly not gel strength. Increasing KOH concentration led to carrageenan containing less sulfate content. In extraction process using alkali, the ion exchange occurred between cation from alkali solution and anion from sulphate in the seaweed. Compared with cation of sodium, the cation of potassium was able to form helixes aggregation indicated by the higher gel strength value. Alkali concentrations affected the gel strength of the extracted carrageenan significantly.ABSTRAKPenelitian ini bertujuan mengembangkan proses ekstraksi karagenan dari rumput laut Eucheuma cottonii dengan mempelajari pengaruh jenis pelarut pada tahap ekstraksi, yaitu air suling, KOH, dan NaOH terhadap rendemen dan sifat gel karagenan.  Ekstraksi dilakukan dengan perbandingan bobot rumput laut – volume pelarut dijaga tetap yaitu 1:50 g/mL pada 80oC. Cuplikan diambil setiap interval waktu tertentu untuk dianalisis. Karagenan dalam filtrat diendapkan dengan etanol dan serat yang dihasilkan dikeringkan sampai bobot konstan. Spektrum infra merah menunjukkan bahwa karagenan yang dihasilkan identik dengan jenis kappa. Air suling merupakan pelarut yang efisien untuk mendapatkan rendemen yang tinggi, tetapi kekuatan gel karagenan yang dihasilkan rendah. Konsentrasi KOH semakin tinggi akan menghasilkan karagenan dengan kadar sulfat semakin rendah dan kekuatan gel meningkat.   Pada tahap ekstraksi menggunakan alkali, terjadi peristiwa pertukaran ion antara kation dalam pelarut dengan ion sulfat dalam rumput laut. Dibandingkan dengan kation Na, kation K mampu membentuk agregasi heliks yang terindikasi berdasarkan kekuatan gel yang lebih kuat

Analisis Pengaruh Variasi Debit Air (QL) dan Debit Gas (QG) terhadap Koefisien Transfer Oksigen (KLa) pada Performa Microbubble Generator

The domestic wastewater treatment plant is usually installed using anaerobic system which has the disadvantage for low conversion process and large volume required. While the effectiveness of aerobic system can be increased by high consumption of energy to supply the oxygen. This study investigates the performance of Microbubble Generator (MBG) for wastewater treatment. The MBG utilizes the hydrodinamics of wastewater flow in the nozzle to provide energy-saving aeration. In this study, the clean water non-steady state test method was selected to find the overall oxygen transfer coefficient (KLa). The experiment was conducted by increasing the concentration of Dissolved Oxygen (DO) using MBG installed with submersible pump (water discharge, QL=80 l/min) and variations of gas discharge (QG) (0.15 l/min and 0.30 l/min). The KLa average results on QL 80 l/min at QG 0.15 l/min showed 0.01996/min and at QG 0.30 l/min showed 0.02564/min. These results indicate that the greater gas discharge (QG) can produce a greater KLa value. This happens because the more air is injected into the water and forms into micro-sized bubbles, the greater the rate of transfer oxygen to the liquid phase

Improved Design of Anaerobic Digesters for Household Biogas Production in Indonesia: One Cow, One Digester, and One Hour of Cooking per Day

A government-sponsored initiative in Indonesia to design and implement low-cost anaerobic digestion systems resulted in 21 full-scale systems with the aim to satisfy the cooking fuel demands of rural households owning at least one cow. The full-scale design consisted of a 0.3 m diameter PVC pipe, which was operated as a conventional plug-flow system. The system generated enough methane to power a cooking stove for ∼1 h. However, eventual clogging from solids accumulation inside the bioreactor proved to be a major drawback. Here, we improved the digester configuration to remedy clogging while maintaining system performance. Controlled experiments were performed using four 9-L laboratory-scale digesters operated at a temperature of 27±1°C, a volatile solids loading rate of 2.0 g VS·L−1·day−1, and a 21-day hydraulic retention time. Two of the digesters were replicates of the original design (control digesters), while the other two digesters included internal mixing or effluent recycle (experimental digesters). The performance of each digester was compared based on methane yields, VS removal efficiencies, and steady-state solids concentrations during an operating period of 311 days. Statistical analyses revealed that internal mixing and effluent recycling resulted in reduced solids accumulation compared to the controls without diminishing methane yields or solids removal efficiencies

Mekanisme Proses Tahap Ekstraksi Karagenan dari Eucheuma Cottonii Menggunakan Pelarut Alkali (The Mechanism Of Carrageenan Extraction From Eucheuma Cottonii Using Alkaline Solvent)

Penelitian ini bertujuan mengembangkan proses ekstraksi karagenan dari rumput laut Eucheuma cottonii dengan mempelajari pengaruh jenis pelarut pada tahap ekstraksi, yaitu air suling, KOH, dan NaOH terhadap rendemen dan sifat gel karagenan. Ekstraksi dilakukan dengan perbandingan bobot rumput laut – volume pelarut dijaga tetap yaitu 1:50 g/mL pada 80oC. Cuplikan diambil setiap interval waktu tertentu untuk dianalisis. Karagenan dalam filtrat diendapkan dengan etanol dan serat yang dihasilkan dikeringkan sampai bobot konstan. Spektrum infra merah menunjukkan bahwa karagenan yang dihasilkan identik dengan jenis kappa. Air suling merupakan pelarut yang efisien untuk mendapatkan rendemen yang tinggi, tetapi kekuatan gel karagenan yang dihasilkan rendah. Konsentrasi KOH semakin tinggi akan menghasilkan karagenan dengan kadar sulfat semakin rendah dan kekuatan gel meningkat. Pada tahap ekstraksi menggunakan alkali, terjadi peristiwa pertukaran ion antara kation dalam pelarut dengan ion sulfat dalam rumput laut. Dibandingkan dengan kation Na, kation K mampu membentuk agregasi heliks yang terindikasi berdasarkan kekuatan gel yang lebih kuat

Evaluasi kecepatan pertumbuhan kristal pada reaksi diikuti kristalisasi pada pembuatan amonium sulfat dari amonia dan asam sulfat

ABSTRACT Chemical reaction followed by crystallization is industrially important because numerous materials are marketed in crystalline form. Its wide use has twofold advantages. Firs!, a crystal formed from an impure solution such as a reaction mixture is usually pure and second, crystalline form has preferable condition for packaging and storing. Beside the good yield and high purity, the most important objective of designing a crystallizer is to control the size range of the crystalline product. Crystal size distribution depends on nucleation and growth rates. When supersaturation can be kept low, such as in fluid-fluid reaction controlled by mass transfer rate. nucleation rate is low enough to be neglected and growth rate dominates the process. A model based on the concept of population density is proposed and then used to evaluate the growth rate. Based on the model proposed and the growth rate obtained, crystal size distribution can be predicted. The growth is assumed to follow LIL Law which states that the growth is independent of the crystal size. The model is verified using plant data from ZA III Plant of P.T. Petrokimia Gresik. It is found that in the operating conditions applied, the crystalline ammonium sulphate grows at constant rate of 0.0511 mm/hour. Having relatively small deviation between data and calculated results of mass fractions at any crystal size ranges, the model can well describe the process

Persepsian Resiko Terhadap Niat Beli Online

This study aims to determine the effect of financial losses and damage to online security reputations and online purchase intention privacy issues as mediating variables. Sources of data used in this study is primary data. Methods of data collection by using a questionnaire. Data analysis using SMART-PLS version 3. The results of the analysis in this study indicate that financial losses have a significant effect on online purchase intentions. while reputational damage has a significant effect on online purchase intentions. Then the results of the analysis in this study indicate that online security and privacy issues affect online purchase intention

Hubungan Kondisi Lingkungan Rumah dan Praktek 3M Plus dengan Kejadian Demam Berdarah Dengue di Wilayah Kerja Puskesmas Air Dingin Kota Padang Tahun 2016

Tujuan Penyakit Demam Berdarah Dengue merupakan masalah kesehatan masyarakat yang utama di Indonesia. Berdasarkan data dari Dinas Kesehatan Kota Padang, pada tahun 2015 di Puskesmas Air Dingin mengalami peningkatan kasus DBD yang cukup signifikan dengan Incidens Rate DBD 361 per 100.000 penduduk. Tujuan dari penelitian ini adalah mengetahui hubungan kondisi lingkungan rumah dan praktek 3M Plus dengan kejadian demam berdarah dengue di wilayah kerja Puskesmas Air Dingin tahun 2016. Metode Penelitan ini menggunakan desain case control, dilakukan di wilayah kerja Puskesmas Air Dingin dari bulan Desember sampai Juni 2016. Sampel terdiri dari 39 kasus dan 39 kontrol dengan matching umur dan tempat tinggal. Pengambilan sampel menggunakan metode Simple Random Sampling. Data diolah dengan menggunakan analisis univariat, bivariat dan multivariat dengan uji statistik Mc Nemar 95% CI dan uji regresi logistik. Hasil Analisis univariat diperoleh 38,4% rumah responden dengan suhu yang baik untuk penularan penyakit DBD, 88,4% rumah responden dengan kelembaban yang baik untuk perkembangan nyamuk, 42,3% rumah responden gelap, 24,3% rumah responden padat penghuni, 28,2% responden menguras TPA >1 minggu, 12,8% responden menutup TPA, 62,8% responden tidak biasa mengubur barang bekas, 83,3% responden tidak menggunakan kassa dan 48,7% responden menggantung pakaian. Analisis bivariat diperoleh suhu rumah pvalue=0,065, kelembaban rumah pvalue=0,687, pencahayaan pvalue=0,002, kepadatan hunian rumah pvalue=0,359, menguras TPA pvalue=0,359, menutup TPA pvalue=0,179, mengubur barang bekas pvalue=0,002, penggunaan kassa nyamuk pvalue=0,179, menggantung pakaian pvalue=0,014. Analisis multivariat didapatkan faktor risiko dominan adalah pencahayaan (pvalue=0,029 OR = 3,347). Kesimpulan Tiga variabel yang mempunyai hubungan dengan kejadian DBD yaitu pencahayaan, praktek mengubur/membuang barang bekas dan menggantung pakaian. Faktor risiko yang paling mempengaruhi kejadian DBD adalah pencahayaan. Disarankan agar petugas kesehatan meningkatkan penyuluhan tentang peniadaan sarang nyamuk di dalam rumah. Daftar Pustaka : 40 (1992-2015) Kata Kunci : DBD, Lingkungan Rumah, Praktek 3M Plus FACULTY OF PUBLIC HEALTH ANDALAS UNIVERSITY Undergraduate Thesis, June 2016 IRA WIRATNI, Registered Number: 1411216089 THE RELATIONSHIP BETWEEN ENVIRONMENT HOME AND PRACTICE 3M PLUS WITH DENGUE HAEMORRHAGIC FEVER INCIDENCE IN AIR DINGIN PUBLIC HEALTH WORK AREA PADANG CITY YEARS 2016 x+97 pages, 25 tables, 10 pictures, 9 apendicces ABSTRACT Objective Dengue Hermorrhagic Fever is a major public health problem in Indonesia. Data from the Padang city health department, in 2015 in the Air Dingin public health increased significantly DBD case with IR 361 per 100.000 population. The purpose of this study was to knowing relationship between environment home and practice 3M Plus with dengue haemorrhagic fever incidence in Air Dingin public health work area years 2016. Method The design of this research case control. This research was conducted in Air Dingin public health work area from December until June 2016. There are cases and control which is 39 cases and 39 controls with matching age and domicile. The Sampling methode used simple random sampling. The data is processed using univariat analysis, bivariat analysis and multivariat analysis with statistic test by Mc. Nemar 95% CI and regresion logistik test. Result Univariate analysis was obtained 38,4% of the homes of respondents and the temperature is good for disease transmission DBD, 88,4% of respondents houses with good moisture for mosquito development, 42,3% of respondents dark houses, 24,3% of respondents solid houses occupants, 28,2% of respondents drain water reservoirs more than one week, 12,8% of respondents to close water reservoirs, 62,8% of respondents unusual bury thrift, 83,3% of respondents did not use insect screen and 48,7% of respondents hanging clothes. Bivariate analysis obtained the house temperature pvalue=0,065, humidity houses pvalue=0,687, light pvalue=0,002, density residential home pvalue=0,359, drain water reservoirs pvalue=0,359, close water reservoirs pvalue=0,179, bury thrift pvalue=0,002, use insect screen pvalue=0,179, hanging clothes pvalue=0,014. Multivariate analysis found the dominant factor is the lighting (pvalue=0,029 OR=3,34). Conclusion There are three variables that have a significant relationship with the incidence of DBD is the lighting, the practice of burying/dispose of waste products and habit hang clothes. The risk factors that affect the incidence of DBD are lighting. Suggested that medical worker to improve counseling about the annihilation of mosquito breeding in the home. Bibliography : 40 (1992-2015) Keywords : DBD, Environment Home, Practice 3M Plu