PENGGUNAAN BIOFILTER ANAEROB UNTUK MENURUNKAN KADAR PENCEMAR ORGANIK PADA LIMBAH CAIR INDUSTRI TAHU

Limbah cair industri tahu mengandung zat organik yang tinggi seperti BOD5 dan COD sehingga perlu adanya pengolahan sebelum dibuang ke lingkungan. Salah satu alternatif pengolahan yaitu menggunakan sistem biofilter anaerob. Penelitian ini bersifat eksperimental yang bertujuan untuk mengetahui penurunan kadar BOD5 dan COD pada limbah cair industri tahu menggunakan sistem biofilter anaerob. Reaktor yang digunakan terdiri dari 2 buah reaktor dan terbuat dari kaca dengan ketebalan 10 mm. Reaktor pertama bervolume 0,081 m3 yang diisi dengan media batu kerikil setinggi 70 cm dan reaktor kedua bervolume 0,059 m3 diisi dengan media bioball rambutan setinggi 45 cm. Limbah cair industri tahu dialirkan ke dalam reaktor biofilter anaerob secara kontinyu dengan arah aliran down flow. Parameter yang diukur yaitu kadar BOD5 dan COD pada inlet maupun outlet reaktor biofilter anaerob. Reaktor 1 bermedia batu kerikil mampu menyisihkan kadar BOD5 dengan penyisihan tertinggi terjadi pada waktu operasi hari ke-4 yaitu sebesar 943,8 mg/L dan penyisihan kadar COD tertinggi pada waktu operasi hari ke-4 yaitu sebesar 1931,2 mg/L. Sedangkan pada reaktor 2 bermedia bioball rambutan mampu menyisihkan kadar BOD5 dengan penyisihan tertinggi terjadi pada waktu operasi hari ke-4 yaitu sebesar 936,7 mg/L dan penyisihan kadar COD tertinggi pada waktu operasi hari ke-4 yaitu sebesar 1856,6 mg/L. Kata Kunci : batu kerikil, bioball rambutan, biofilter anaerob, limbah tahu. Tofu industrial liquid waste contains high organic matter such as BOD5 and COD so it needs processing before being discharged into the environment. One of alternative processing is using an anaerobic biofilter system. This study is experimental which aims to determine the decrease of BOD5 and COD levels in tofu wastewater using anaerobic biofilter system. The reactor consist is 2 reactors and is made of glass with a thickness of 10 mm. The first reactor with a volume of 0.081 m3 was filled with 70 cm of gravel media and a second reactor with a volume of 0.059 m3 filled with 45 cm of rambutan bioball media. Tofu industrial liquid waste is flowed into the anaerobic biofilter reactor continuously with down flow direction. Parameters measured were BOD5 and COD levels at the anaerobic biofilter reactor inlet and outlet. The highest removal of BOD5 levels in reactor 1 with gravel media occurred on the 4th day of operation with a allowance of 943.8 mg/L and the highest removal of COD levels at the 4th day of operation was 1931.2 mg/L. Whereas the highest removal of BOD5 levels in reactor 2 with rambutan bioball media occurred on the 4th day of operation with a allowance of 936.7 mg/L and the highest removal of COD levels at the 4th day of operation with a allowance of 1856.6 mg/L. Keywords: anaerobic biofilter, gravel stone, rambutan bioball, tofu waste.

Scour downstream of a corrugated apron under wall jets

Experiments were performed over smooth and corrugated aprons with different corrugation dimensions to study the scour and flow characteristics under submerged wall jets condition. The scour depth and length are significantly lower for corrugated than smooth rigid aprons. The maximum reductions in scour depth and length are 79 and 83%, respectively. Optimum scour depth and length are found for aspect ratio (ratio of corrugation wave length to amplitude) three for corrugated apron. The factors affecting scour depth and length were analyzed graphically, and empirical equations are proposed for predicting maximum scour depth and length, and the point of maximum scour depth for corrugated aprons. Velocity, turbulence characteristics, and Reynolds stress in scour holes for smooth and corrugated aprons were also studied. HIGHLIGHT This paper presents the scour downstream of corrugated apron and flow characteristics under submerged wall jets. Here scour depth and length reduces significantly than other apron. In this we have tried to develop empirical equation on single size sediment considering all the flow parameter and apron parameter. Besides this we have also conducted study related to turbulence and shear stress and velocity vector profile.

Numerical Analysis of Engine Exhaust Flow Parameters for Resolving Pre-Turbine Pulsating Flow Enthalpy and Exergy

Energy carried by engine exhaust pulses is critical to the performance of a turbine or any other exhaust energy recovery system. Enthalpy and exergy are commonly used concepts to describe the energy transport by the flow based on the first and second laws of thermodynamics. However, in order to investigate the crank-angle-resolved exhaust flow enthalpy and exergy, the significance of the flow parameters (pressure, velocity, and temperature) and their demand for high resolution need to be ascertained. In this study, local and global sensitivity analyses were performed on a one-dimensional (1D) heavy-duty diesel engine model to quantify the significance of each flow parameter in the determination of exhaust enthalpy and exergy. The effects of parameter sweeps were analyzed by local sensitivity, and Sobol indices from the global sensitivity showed the correlations between each flow parameter and the computed enthalpy and exergy. The analysis indicated that when considering the specific enthalpy and exergy, flow temperature is the dominant parameter and requires high resolution of the temperature pulse. It was found that a 5% sweep over the temperature pulse leads to maximum deviations of 31% and 27% when resolving the crank angle-based specific enthalpy and specific exergy, respectively. However, when considering the total enthalpy and exergy rates, flow velocity is the most significant parameter, requiring high resolution with a maximum deviation of 23% for the enthalpy rate and 12% for the exergy rate over a 5% sweep of the flow velocity pulse. This study will help to quantify and prioritize fast measurements of pulsating flow parameters in the context of turbocharger turbine inlet flow enthalpy and exergy analysis.

A Key Flow Parameter to the Profile Loss of Low-Pressure Turbine Blades

For an optimum performance design of low-pressure turbine (LPT) blades, it is crucial to understand the generation mechanism of profile loss properly. As the profile loss is usually taken to be the loss generated inside the blade boundary layer due to viscous effects, most of the efforts for the performance optimization have concentrated on the reduction in the boundary layer loss using the flow parameters that represent the loss generation in the boundary layers. Kodama and Funazaki [1] investigated the generation mechanism of profile loss from a view point of blade drag forces, friction drag force and pressure drag force, and suggested that the loss due to pressure drag is dominant in the profile loss of a typical LPT blade. The loss due to pressure drag is not a boundary layer loss that is generated in the boundary layers, but a mixing loss that is generated downstream of the trailing edge. It is necessary to clarify a key flow parameter to the loss due to pressure drag for an effective performance optimization. This paper aims at investigating the flow parameter that is a measure of the profile loss. In the investigation, the profile loss is broken down into the loss components which are expressed by the boundary layer integral parameters at the trailing edge. Then the loss components are categorized into the loss due to friction drag or the loss due to pressure drag. The loss level of each component is evaluated by using the results of steady Reynolds Averaged Navier-Stokes (RANS) simulations to assess the contribution to the total profile loss. The evaluations are conducted for two kinds of blade profiles at three different Reynolds numbers. It is found that the largest contributor to the loss due to pressure drag, consequently to the total profile loss, is the loss associated with a mixing of accelerated free stream flow by the flow blockage at the trailing edge plane. The loss level is simply determined by the flow blockage. This suggests that the flow blockage at the trailing edge plane is the most important flow parameter for an optimum performance design of LPT blades.

Entropy-based myocardial blood flow measurements using PET: a way to improve reproducibility

Funding Acknowledgements Type of funding sources: None. Background and purpose Myocardial blood flow (MBF) measurements using PET are increasingly used to guide the management of patients with (suspected) coronary artery disease (CAD). Day-to-day variability of these measurements is poor with a 21% standard deviation or 40% 95%-confidence interval [Reference: JACC Cardiovasc Imaging, 2017;10(5):565]. This limits clinical applicability in diagnosis, risk stratification and follow-up as these all depend on comparison of flow values with fixed cut-off values. We expect that reproducibility can be improved by combining flow measurements with the variation of flow values within the myocardium. As entropy is a measure of variability of the associated distribution, we compared the reproducibility of an entropy-based flow parameter with that of conventional myocardial flow reserve (MFR) measurements. Methods We performed a study using intra-individual comparison in 24 patients who underwent rest and regadenoson-induced stress myocardial perfusion imaging using Rubidium-82 on two different PET systems (PET1: Discovery 690, GE Healthcare, and PET2: Vereos, Philips Healthcare) within 3 weeks. MBF for both rest and stress was calculated using Lortie’s one-tissue compartment model (Corridor4DM, INVIA). MFR (ratio of MBF stress/rest) was determined for the myocardial as a whole (MFRglobal), for the three vascular territories: LAD, LCX and RCA (MFRregional) and for the 17 segments. Next, we calculated Shannon’s entropy to measure the variation of the 17 MFR segmental values. We multiplied Shannon’s entropy by the mean of the MFR segmental values resulting in an entropy-based MFR (MFRentropy). For each patient MFRglobal, MFRregional and MRFentropy were compared between both PET systems. For each of the three parameters the test-retest precision was calculated as the SD of the relative difference between measurements. Results The mean difference in MFR measurements between both cameras did not differ from zero (p > 0.05). Mean values for PET1 were MFRglobal = 2.4, MFRregional = 2.4 (LAD), 2.4 (LCX) and 2.5 (RCA), and MFRentropy = 2.4. For PET2 we found MFRglobal = 2.5, MFRregional = 2.5 (LAD), 2.4 (LCX) and 2.6 (RCA), and MFRentropy = 2.5. Test-retest precision was lower for MFRentropy with 11% compared to that of MFRglobal (21%), MFRregional LAD (22%), MFRregional LCX (23%) and MFRregional RCA (24%) (p < 0.01). Conclusion The reproducibility of myocardial flow reserve measurements using Rubidium-82 PET improved by a factor of 2 when an entropy-based flow parameter instead of global or regional MFR parameters is used. This entropy-based flow-parameter may be used to better discriminate ischemia from non-ischemia and may therefore improve CAD management.

CONCEPTUAL PROVISIONS FOR PREDICTION OF STATE AVIATION AIRCRAFT NO-FAILURE INDICATORS

A conceptual approach to predicting of aircraft no-failure indicators during operational use is proposed. This approach is based on the use of methods of statistical analysis of operational data for a certain period of time. The results of predicting the failure flow parameter using a combined model of acceptable level and their standard deviation are presented. The results of predicting can be used to control the reliability (no-failure operation) of aircraft equipment in order to make grounded decisions about the continued operation of their equipment beyond the established life service. In order to create highly reliable aircraft it is necessary to predict failure rates, which involves the establishment of their range and quantitative values. To predict the thresholds of failure of the aircraft, it is advisable to use the following interval indicators of reliability: Ricao “accident level” indicator, which takes into account the number of flight failures detected in 100 hours and actually determines the dynamics of changes in the level of flight safety; “failure flow parameter, ω (t)”, which takes into account the total number of failures per hour of flight and determines the dynamics of changes in the level of operational The predicted value of the indicator of the “reliability upper control limit”, which determines the limit level of operatioanl reliability, at which further reliable operation of the aircraft is not desirable. According to the concept of “acceptable level of safety performance”, predictions of indicators for three levels of flight safety (acceptable, target, critical) are calculated, which need to be monitored in future periods of aircraft operation and make certain management decisions according to the proposed algorithm. The results of calculation for prediction indicators of reliability for specific types of aircraft according to their operation in the period 2017-2019 are presented.

Practical Design of Flow Meter for Mechanical Ventilation Equipment

This paper introduces a practical technique for the design of an instrument used in air flow measurement or flowmeter. This instrument is an essential component in the hospital medical ventilation equipment functioning, therefore, the parameters design presented in this article focus on this purpose. However, this instrument can be employed to any measurement scale. The technique is based on indirect flow measurement, using a sensor that converts the flow parameter into a differential pressure measurement. An electronic transducer allows the differential pressure values to be obtained as an electrical signal, which is then digitized and analyzed to obtain the original parameter. The experimental procedure presented in this paper utilizes a computational algorithm to perform the signal analysis; however, given the simplicity of the procedure, this could be adapted to any digital processing card or platform, to show the measurement obtained immediately. Preliminary analyses demonstrated instrument efficiency with sensitivity of 0.0681 L/s. Accuracy evaluation showed an average measurement error lesser than 1.4%, with a standard deviation of 0.0612 and normal distribution over the set of test measurements.

Irreversibility Analysis in Darcy-Forchheimer Flow of Nanofluid by a Stretched Surface

The aim of this articles is to investigate the entropy optimization in unsteady MHD flow Darcy-Forchheimer nanofluids towards a stretchable sheet. The surface we tend to think about is porous and stretchy under acceleration. Flow occurs due to the stretching of the surface. Four distinct types of aqueous nanostructures are taken in this examination where copper oxide (CuO), copper (Cu), titanium dioxide (TiO2) and aluminum oxide (Al2O3) are the nanoparticles. Irreversibility analysis are discussed through second law of thermodynamics. The expression of energy is mathematically designed and discussed according to heat generation / absorption, dissipation, thermal radiation, and joule heating. The nonlinear PDE (partial differential conditions) is first changed to ODE (normal differential conditions) through the use of appropriate similarity variables. Here we used the numerically embedded solution technique to develop a numerical result for the obtained nonlinear flow expression. Influence of various flow parameter velocity temperature distribution and entropy generation are discussed. Reduction occurs in velocity profile for larger porosity and magnetic parameters. An enhancement in entropy generation and temperature distribution is seen for Brinkman number. An opposite effect is noticed in velocity and temperature through solid volume friction.