Kinetics of Phenol Degradation in Aqueous Solution Oxidized under Low Frequency Ultrasonic Irradiation

Phenol is categorized as a refractory pollutant and its presence in water stream is strictly limited according to the government regulation. The present study investigated the degra-dation of phenol in aqueous solution by the effect of ultrasound. The process took place in a 500 ml glass reactor equipped with magnetic stirring and irradiated by low frequency (28 kHz) ultrasound from a horn type probe. Ultrasonic irradiation was found to enhance oxidation rates at ambient conditions, compared to other approaches. Optimum conditions were observed at a stirring speed of 400 rpm and temperature of 30 C in acidic solution. It was revealed that the phenol degradation was the first order kinetics with respect to phenol. A low value of the activation energy 6.04 kcal/mol suggested that diffusional steps were rate determining during the phenol decomposition. It also confirmed that phenol was mostly degraded in the film region and less occurred in the bulk solution

Modifikasi Model Penjalaran Gelombang Multi Arah

In this paper we derived a modification of the model of waves evolution in two-directional spatial coordinates. Using KP equation as the basic model, we improved dispersive property in spatial x coordinate and named it as improved KP (iKP) equation. iKP has an exact dispersion relation in spatial x coordinate. Using this model, we derived second order regular waves and analyzed the expression of Maximum Temporal Amplitude

A Preliminary Study of the Application of Electromagnetic Conductivity Meter on Soil Properties of Paddy Cultivation Areas at Wue Village, Jantho, Aceh Besar District, Indonesia

Conventional soil sampling is time consuming and requires meticulous laboratory analysis. Hence, mapping of soil apparent in respect to electrical conductivity (ECa) has been developed to identify areas of contrasting soil properties. Such ECa values are represent measures of soil properties. The sensor system, GF Instrument model CMD-4 were used to analyze soil physical properties. This system consists of three important parts, ECa sensor, data logger and Global Positioning System (DGPS) receiver. This research was aimed to evaluate the relationships between ECa and soil properties as well as the yield of rice (paddy) in paddy\u27s farming fields. One study site was chosen. The sensor was pulled through a plotted area of 0.25 km2. The distribution map of ECa was developed to identify the contrast of ECa. More than 100 ECa of data points were collected in 3-hour for the large plot. The data was later transferred to a notebook computer for generation of ECa maps using Surfer 11 software. According to the data analyses, field and ECa showed positive correlation. The average values of ECa are significantly different between hilly area and drainage canal area signifying differences in soil structure. Soil ECa could provide a measure of the spatial differences associated with soil physical and chemical properties, which for paddy soil may be a measure of soil suitability for crop growth and its productivity. This sensor can measure the soil ECa through the field quickly for detailed features of the soil and can be operated by just one worker. The ECa map provides some ideas for future soil managemen

Kajian Teknis Penirisan Tambang Nikel Laterit Mengunakan Metode Mine Dewatering

Air akan menjadi sumber masalah dalam area penambangan, sehingga perlu dilakukan penanganan yang baik agar tidak mengakibatkan kerugian bagi Perusahaan dan masyarakat. Tujuan dari penelitian ini untuk mengetahui jumlah pompa yang dibutuhkan dan waktu kerja pompa pada area penambangan nikel laterit di morowali Sulawesi tengah. Metode yang dipakai yaitu mine dewatering system. Pengamatan di lapangan terlihat adanya catchment area yang luas dan berada di sekitar pit penambangan dengan luasan 37,6Ha. Curah hujan rata-rata maksimum pada lokasi penelitian yaitu 23,82 mm/hari. Curah hujan rencana diambil periode ulang dua tahun sebesar 22,74 mm/hari dan intensitas hujan terbesar 7,88 mm/jam. Besarnya curah hujan maksimal bulanan pertahun yaitu 1.286,00 mm sehingga diketahui besarnya air limpasan yang akan masuk ke sump 483,56 m3/bulan atau 17,26 m3/hari dengan ketentuan 1 bulan sama dengan 28 hari. Kemampuan pompa berdasarkan head total pompa 48,67 m, dan kemampuan hasil koreksi pompa yaitu 0,15 m3/detik. Dibutuhkan empat pompa dengan jenis yang sama dengan waktu kerja efektif 8,5 jam/hari. Debit air yang akan masuk ke dalam parit 0,47 m3/detik dan parit yang akan dibuat harus mampu mengalirkan air, maka parit dibuat berbentuk trapesium. Berdasarkan hasil penelitian disimpulkan bahwa dibutuhkan 4 unit pompa yang bekerja selama 8,5 jam perhari, dan dibuatkan kolam pengendapan untuk penetralan air

Quadsim Version 2.1 Student Manual

Quadsim is an intermediate code simulator. It allows you to "run" programs that your compiler generates in intermediate code format. Its user interface is similar to most debuggers in that you can step through your program, instruction by instruction, set breakpoints, examine variable values, and so on. The intermediate code format used by Quadsim is that described in [Aho 86]. If your compiler generates intermediate code in this format, you will be able to take intermediate-code files generated by your compiler, load them into the simulator, and watch them "run." You are provided with functions that hide the internal representation of intermediate code. You can use these functions within your compiler to generate intermediate code files that can be read by the simulator. Quadsim was inspired and greatly influenced by [Aho 86]. The material in chapter 8 (Intermediate Code Generation) of [Aho 86] should be considered background material for users of Quadsim

Peran Faktor Penyekala Pada Konstruksi Interpolasi Fraktal

: It is known that a fractal functions that interpolated the data such that , can be constructed from an Iterated Function System (IFS) based on The Fixed Point Theorem on contractive mappings. By taking a certain Affine Mapping, which is a form of contractive mapping on IFS, the existence of IFS\u27 attractor can be proven as the fractal interpolan of related data. The vertical scaling factor contained in the affine mapping role as a necessary condition of existence and uniqueness of a fractal interpolation function data. The necessary condition of is on the interval

CREDIT RATING AGENCIES AND THEIR POTENTIAL IMPACT ON DEVELOPING COUNTRIES

Credit rating agencies (CRAs) play a key role in financial markets by helping to reduce the informative asymmetry between lenders and investors, on one side, and issuers on the other side, about the creditworthiness of companies or countries. CRAs´ role has expanded with financial globalization and has received an additional boost from Basel II which incorporates the ratings of CRAs into the rules for setting weights for credit risk. Ratings tend to be sticky, lagging markets, and overreact when they do change. This overreaction may have aggravated financial crises in the recent past, contributing to financial instability and cross-country contagion. The recent bankruptcies of Enron, WorldCom, and Parmalat have prompted legislative scrutiny of the agencies. Criticism has been especially directed towards the high degree of concentration of the industry. Promotion of competition may require policy action at national and international level to encourage the establishment of new agencies and to channel business generated by new regulatory requirements in their direction.

Mitigating Electricity a Price Spike under Pre-Cooling Method

The growing demand for air-conditioning is one of the largest contributors to Australia overall electricity consumption. This has started to create peak load supply problems for some electricity utilities particularly in Queensland. This research aimed to develop a consumer demand side response model to assist electricity consumers to mitigate peak demand on the electrical network. The proposed model allows consumers to independently and proactively manage air conditioning peak electricity demand. The main contribution of this research is how to show consumers can mitigate peak demands by optimizing energy costs for air conditioning in a several cases such as no spike and spike considering to the probability spike cases may only occur in the middle of the day for half hour, one hour and one and half hour spikes. This model also investigates how air conditioning applied a pre-cooling method when there is a substantial risk of a price spike. The results indicate the potential of the scheme to achieve energy savings and reducing electricity bills (costs) to the consumer. The model was tested with the Queensland electricity market data from Australian Energy Market Operator and Brisbane temperature data from Bureau statistic during hot days

Optimise Energy Cost for Air Conditioning based on the Market Price under Demand Side Response Model

The increasing contribution of air conditioning (AC) to energy consumption has received considerable attention in the past and will continue to do so in the coming years, from Indonesian government, state electricity company and consumers. Managing demand on the electricity system in peak sessions is the most direct way to address the AC peak demand issue. The aim of this research is to developed a consumer demand side response (DSR) model to assist both electricity consumers/aggregator and electricity provider to minimise energy cost if peak price occured in the peak season. The proposed model allows consumers to independently and proactively manage air conditioning load through an aggregator. This research examines how the control system applies DSR model if a price spike may occur at 18.00 during one hour. The results indicate, consumer and aggregator could gain collective benefits when the consumer controls the air conditioning under the DSR program. The model was tested in Makassar City South Sulawesi considering to the caharacteristic of the room and air conditioning in a residential house