Ensemble data assimilation for systems with different degrees of nonlinearity with a hybrid nonlinear-Kalman ensemble transform filter

<p>The second-order exact particle filter NETF (nonlinear ensemble transform filter) is combined with local ensemble transform Kalman filter (LETKF) to build a hybrid filter scheme (LKNETF). The filter combines the stability of the LETKF with the nonlinear properties of the NETF to obtain improved assimilation results for smaller ensembles. Both filter components are localized in a consistent way so that the filter can be applied with high-dimensional models. The degree of filter nonlinearity is defined by a hybrid weight, which shifts the analysis between the LETKF and NETF. Since the NETF is more sensitive to sampling errors than the LETKF, the latter filter should be preferred in linear cases. It is discussed how an adaptive hybrid weight can be defined based on the nonlinearity of the system so that the adaptivity yields a good filter performance in linear and nonlinear situations. The filter behavior is exemplified based on experiments with the chaotic Lorenz-63 and Lorenz-96 models, in which the nonlinearity can be controlled by the length of the forecast phase.</p>

The Improving Of Higher-Order Thinking Skills As Information Filter For Alpha Generation

This paper's aim is to describe the strategy to improve the ability to think at a higher level for children currently in primary education. Children currently in primary education are children who are in the Alpha generation. This generation is certainly different from previous generations, especially in access to information. Even children holding a device in daily life is not a strange sight. This fact needs to be examined more about the balance in the speed of obtaining information and managing it. The more accessible access to information is, the expectation is children have a good filter for news or information that is classified as reasonable and vice versa, namely information that is classified as not making sense. The ability to filter this information is not easily obtained by every child. In other words, children need a stimulus to be able to think at a high level. The goal is that when children can think at a high level, then that ability is used as a weapon to gain the ability to filter information. In this paper, the focus of discussion is a strategy that should be taught by adults around the children to be able to be wiser in managing information. This research applies a qualitative approach with a literature study. The finding is the ability for the children to think at a higher level can improve with learning through contextual problems. This contextual problem is obtained from daily activities carried out by children

Perspektif Remaja Terhadap Dakwah Online Studi Empiris Pada Siswa MA Hasanuddin Siraman Kesamben Blitar

Judging from the times, we will increasingly understand that life goes fast. Good filter ability is a key indicator that everyone must have in facing this development. This article is the result of research that leads to the development of the digital world, especially in the field of online that touches almost all aspects of life. One that attracts researchers is the entry of the online world into the realm of da'wah. Conventional da'wah is done face-to-face, now has experienced many shifts and shifts through online media with the intention of facilitating access. The purpose of writing this article is to analyze adolescent perceptions about online propaganda and preaching methods that are of interest to adolescents with empirical studies of MA students Hasanuddin Siraman, Kesamben, Blitar. This descriptive-qualitative article directly observes adolescents at MA Hasanuddin about their perceptions of online da'wah and the method of da'wah that appeals to adolescents. The selection of adolescents as research subjects is because researchers find data that users of the digital or online world are the most widely held by adolescents, so that indirectly adolescents have the possibility of accessing da'wah online. The method used for this research is observation, interview, and documentation. The data obtained will then be matched using data triangulation techniques to be able to obtain data validity. The results of this study in the form of adolescent perceptions of online propaganda and propaganda methods are in demand by adolescents in this millennial era

COMPARISION OF FOUR FABRICS FOR FILTERING TURBID WATER IN A TWO STAGE CROSS-FLOW FILTER

Surface water treatment plants in Trinidad are incapable of filtering highly turbid water. Water treatment operations are shut down whenever turbidity levels rise during or after rainfall. The aim of this research is to determine the physical properties of linen, burlap, crepe-backed satin and cotton fabrics and to compare their efficiencies as filter media for reducing turbidity in water. Scanning electron microscopy was used to generate images of each fabric. Fabric weave type was determined. Inter-yarn pore sizes, inter-fiber pore sizes, warp and weft spacings, warp and weft diameters and thicknesses were measured using ImageJ. Based on the properties examined, and execution of cross-flow filtration and perpendicular filtration tests, linen was the chosen fabric filter medium. Surface profilometry resulted in linen having the roughest surface of 685.5µm and the largest maximum profile height of 3632.4µm. Linen’s inter-yarn and inter-fiber pore sizes were 41.98µm and 22.37µm respectively. This fabric had warp and weft spacings of 400µm and 700µm respectively and was 400.39µm thick. Measurements also revealed warp and weft diameters of 13.26µm and 14.96µm respectively. Linen had a high tensile strength of 402N. Linen, had a hopsack plain weave and was tightly woven; it was 95.16% porous with a sediment retention capacity of 71%. Linen is a fabric material that could prove to be a very good filter medium. Also, Acono River water turbidity levels measured ranged from 2.47NTU to 23.93NTU. Soil types contained in the turbid water were gravels, sand and silt varying from 25mm to 0.075mm in size.

The Use of Bauxite as an Arsenic Filter

Arsenic (As) has the potential to negatively affect soils and groundwater quality, and cause several public health challenges. It is usually concentrated and released during metal mining of ores that contains arsenic-bearing minerals. Remediation strategies are in place to avoid pollution. In this study, bauxite from Awaso, Ghana, was characterised, and its ability to sequester As was tested under varying conditions of temperature, Eh and pH. The study showed that the best particle size in the range utilised was 80% passing 2 mm as it allowed easy percolation, and As removal was about 95%. The reaction is a favourable pseudo-second order reaction that is spontaneous and thermodynamically stable and compares well with the Langmuir Sorption Isotherm. About 80% sorption was achieved within 20 minutes of contact with low desorption rate of less than 1.8%. The study thus concludes that bauxite is a good filter for arsenic. Keywords: Arsenic, Bauxite, Filter, Sorption, Isotherm

OPTIMIZING SURFACE ELECTROMYOGRAPHY ACQUISITION WITHOUT RIGHT LEG DRIVE CIRCUIT

The right leg drive (RLD) is a circuit associated with electrocardiography acquisition circuits. For electromyography (EMG), the RLD circuit is used to a lesser degree. In general, the RLD circuit provides better noise reduction. This study compares the output of the EMG with and without the RLD circuit. The results indicate that with a good filter design, the direct grounding method can match the RLD in terms of noise reduction. As a result, EMG application, the RLD drive can be omitted.

Optimization of air permeability of spunlaced filter fabrics using the Box–Behnken experimental design

One of the most important characteristics that a filter must possess is high air permeability. A good filter fabric must be able to capture the dust particles while maintaining a good airflow through it in order to reduce high pressure drop. Therefore, producing a filter fabric with the desired air permeability can be challenging as several process parameters such as fiber types, area weight and water jet pressure will interact with each other during spunlacing process and influence the fabric air permeability. To study the effects of these independent variables on the air permeability of three different types of spunlaced fabrics, the Box–Behnken design was used to model their effects. The fibers used were polyacrylonitrile, polyphenylene sulfide and blend of polyphenylene sulfide/polyimide. In addition, filtration properties of some of the filter samples were also evaluated. Based on the effects of the fiber types, area weight and water jet pressure on the fabric air permeability, the optimum conditions for achieving higher air permeability were fiber types (+1 level), area weight (0 level) and pressure (−1 level), respectively. The air permeability of the fabrics decreased with increasing water jet pressure for all fiber types and increasing area weight decreased the air permeability. It was observed that the independent variables had a significant effect on the air permeability. Filtration efficiency of the selected filters samples were ≥95%. Among the selected samples, polyphenylene sulfide/polyimide (440 g/m2) fabric has the lowest pressure drop whereas polyacrylonitrile (560 g/m2) has the highest pressure drop.

Beyond the Construction, Design and Planning Scenarios of Eco-Buildings

Lately, even in Romania, the interest in ecological homes has begun to take on proportions. Hugged by curiosity, but especially by reorienting towards a (more) healthier lifestyle, people seek to find out as much detail as possible about them - thus capturing the outline and the present work. Although eco-house construction is simple and eliminates many of the heavy stages of a classical construction, future homeowners omit, due to lack of information, this option, especially in the context in which we do not have a good filter of information about this subject, which will give us the real benefits we have. Ecologic houses seem to be a trend with strong growth, because the shapes that they can wear are extremely varied. The great variety, low price and promise of ecological housing is likely to convince people to completely change their lifestyle. How well are we prepared for sustainable development? How do we meet the demands of today's society? What does a green house look like, how does it behave in time, and how much does it cost? What are the trends in designing a green house? These are just a few questions that we will answer during the work.

Novel biofilm reactor for denitrification of municipal wastewater

A pilot-scale CFIC® (continuous flow intermittent cleaning) reactor was run in anoxic conditions to study denitrification of wastewater. The CFIC process has already proven its capabilities for biological oxygen demand removal with a small footprint, less energy consumption and low cost. The present study focused on the applicability for denitrification. Both pre-denitrification (pre-DN) and post-denitrification (post-DN) were tested. A mixture of primary treated wastewater and nitrified wastewater was used for pre-DN and nitrified wastewater with ethanol as a carbon source was used for post-DN. The pre-DN process was carbon limited and removal rates of only 0.16 to 0.74 g NOx-N/m²-d were obtained. With post-DN and an external carbon source, 0.68 to 2.2 g NO3-Neq/m²-d removal rates were obtained. The carrier bed functioned as a good filter for both the larger particles coming with influent water and the bio-solids produced in the reactor. Total suspended solids removal in the reactor varied from 20% to 78% (average 45%) during post-DN testing period and 9% to 70% (average 29%) for pre-DN. The results showed that the forward flow washing improves both the DN function and filtration ability of the reactor.