Modeling non-equilibrium mass transport in biologically reactive porous media.

We develop a one-equation non-equilibrium model to describe the Darcy-scale transport of a solute undergoing biodegradation in porous media. Most of the mathematical models that describe the macroscale transport in such systems have been developed intuitively on the basis of simple conceptual schemes. There are two problems with such a heuristic analysis. First, it is unclear how much information these models are able to capture; that is, it is not clear what the model's domain of validity is. Second, there is no obvious connection between the macroscale effective parameters and the microscopic processes and parameters. As an alternative, a number of upscaling techniques have been developed to derive the appropriate macroscale equations that are used to describe mass transport and reactions in multiphase media. These approaches have been adapted to the problem of biodegradation in porous media with biofilms, but most of the work has focused on systems that are restricted to small concentration gradients at the microscale. This assumption, referred to as the local mass equilibrium approximation, generally has constraints that are overly restrictive. In this article, we devise a model that does not require the assumption of local mass equilibrium to be valid. In this approach, one instead requires only that, at sufficiently long times, anomalous behaviors of the third and higher spatial moments can be neglected; this, in turn, implies that the macroscopic model is well represented by a convection–dispersion–reaction type equation. This strategy is very much in the spirit of the developments for Taylor dispersion presented by Aris (1956). On the basis of our numerical results, we carefully describe the domain of validity of the model and show that the time-asymptotic constraint may be adhered to even for systems that are not at local mass equilibrium

Purchasing Power, Fruits Vegetables Consumption, Nutrition Status Among Elementary School Student

Food purchasing power is usually defined as a household\u27s economic ability to obtain food which is determined by measuring the income allocated for food purchase, the price of food consumed, and the number of family members. More than 50% of the sub-districts in South Central Timor are vulnerable to food consumption due to their low purchasing power, thus causing low fruits and vegetables consumption. To analyze the correlation between purchasing power, fruits and vegetables consumption, with nutrition status of elementary school students. Analytic observational using a cross sectional design. Sample size of 108 students was achieved using simple random sampling method. Independent variables are purchasing power, fruits and vegetables consumption. Dependent variable is nutrition status. Fruits and vegetables consumption data was collected using food frequency, purchasing power data was collected using questionnaires, and nutrition status was collected by calculating IMT/U. The statistics tests used were chi square test. The mean number of fruits and vegetables consumption of the elementary students was 0,36±0,483 and the mean number of purchasing power was 2,80±0,405. Bivariate study test results show a significant correlation between purchasing power and nutrition status (p=0,039) and a significant correlation between fruits and vegetables consumption and nutrition status (p=0,000). There is a correlation between purchasing power, fruits and vegetables consumption, and nutrition status in elementary school students

Correspondence Between One- and Two-Equation Models for Solute Transport in Two-Region Heterogeneous Porous Media

In this work, we study the transient behavior of homogenized models for solute transport in two-region porous media. We focus on the following three models: (1) a time non-local, two-equation model (2eq-nlt). This model does not rely on time constraints and, therefore, is particularly useful in the short-time regime, when the timescale of interest (t)is smaller than the characteristic time (τ1) for the relaxation of the effective macroscale param-eters (i.e., whent ≤τ1); (2) a time local, two-equation model (2eq). This model can be adopted when (t) is significantly larger than (τ1) (i.e., whent τ1); and (3) a one-equation, time-asymptotic formulation (1eq∞). This model can be adopted when (t) is significantly larger than the timescale (τ2) associated with exchange processes between the two regions(i.e., when t τ2). In order to obtain insight into this transient behavior, we combine a theoretical approach based on the analysis of spatial moments with numerical and analytical results in several simple cases. The main result of this paper is to show that there is only a weak asymptotic convergence of the solution of (2eq) towards the solution of (1eq∞)in terms of standardized moments but, interestingly, not in terms of centered moments. The physical interpretation of this result is that deviations from the Fickian situation persist in the limit of long times but that the spreading of the solute is eventually dominating these higher order effects

Optimasi Proses Injeksi Dengan Metode Taguchi

At this time about 3% of products produced by "X" plastic factory does not reach the standard. This factory has a problem to minimize the amount of defects. Taguchi method is used to lower the level of product defects. From the field survey, all the suspected factors can be obatained and it is shown ini the fishbone diagram. From the suspected factors, the factory chose factors that are to be used ini the experiments. Experiments were conducted using those four factors : pellet material percentage (60%, 70%, 80%), temperature (217°C, 225°C, 233°C), injection pressure (92 Bar, 93 Bar, 94 Bar), screw speed (81%, 83%, 85%). Taguchi method provide the combination and number of experiments. From each level of defects condition, analysis was done to obtain the affecting variables. The results of analysis shows that the combination of pellet material (80%), temperature (225°C), injection pressure (93 Bar), screw speed (83%) can minimize the amount of defects to 0.3%

Analisis Sistem Pemasaran Stroberi pada Koptan Bali Buyan Berry di Desa Pancasari Kabupaten Buleleng

Analysis of Marketing System Strawberry on Koptan Bali Buyan Berry in the Village of Pancasari District Buleleng The study aims to determine of the function, structure, conduct and the performance of the market. Data used in this study is qualitative data and quantitative data, the data obtained and analyzed. The results showed on the functioning of the market there are three functions, namely market exchange, physical and facilities. Total of marketing agencies that are in the market structure as much as 1 merchant wholesalers, traders inter-city, inter-island trader and 4 retailers. Pricing in the study by bargaining and how to pay the monthly farmers with cash, the inter-city merchant cash once a month, on the inter-island trader bimonthly cash and at retailers with cash paid on the spot. The performance of the market and the marketing margin is calculated with the farmer\u27s share. At first marketing channel marketing margin is IDR 12,000 to the farmer\u27s share of 53.84%, the second marketing channel marketing margin is IDR 14,000 to the farmer\u27s share of 50% and the third marketing channel marketing margin of IDR 17,250 to the farmer\u27s share of 44.48%. Farmers should sell strawberries not only to the marketing agencies that already have the attachment of cooperation in order to obtain a higher sales price

Combined endoscopic endonasal transpterygoid and sublabial transmaxillary approaches for a large infratemporal fossa trigeminal schwannoma

Background Trigeminal schwannomas (TSs) with solitary extracranial location are rare, and surgical excision is challenging. In recent years, the endoscopic endonasal transmaxillary transpterygoid approach (EETPA) has been advocated as an effective strategy for TSs in the infratemporal fossa (ITF). Method We describe the steps of the EETPA combined with the sublabial transmaxillary approach for the surgical excision of a giant mandibular schwannoma of the ITF. Indications, advantages, and approach-specific complications are also discussed. The main surgical steps are shown in an operative video. Conclusion A combined EETPA and sublabial transmaxillary approach represents a safe and effective option for the surgical excision of extracranial TSs