Saturation-Dependence of Dispersion in Porous Media

In this study, we develop a saturation-dependent treatment of dispersion in porous media using concepts from critical path analysis, cluster statistics of percolation, and fractal scaling of percolation clusters. We calculate spatial solute distributions as a function of time and calculate arrival time distributions as a function of system size. Our previous results correctly predict the range of observed dispersivity values over ten orders of magnitude in experimental length scale, but that theory contains no explicit dependence on porosity or relative saturation. This omission complicates comparisons with experimental results for dispersion, which are often conducted at saturation less than 1. We now make specific comparisons of our predictions for the arrival time distribution with experiments on a single column over a range of saturations. This comparison suggests that the most important predictor of such distributions as a function of saturation is not the value of the saturation per se, but the applicability of either random or invasion percolation models, depending on experimental conditions

Job burnout and some of its risk factors on the health workers (Behvarz) in Koohrang County, I.R.Iran, in 2010

زمینه و هدف : فرسودگی شغلی، شامل خستگی عاطفی ، مسخ شخصیت و کاهش موفقیت فردی است و زمانی که توانایی های فرد برای تقاضاهای محیط کار کافی نباشد علائم آن آشکار می شود. کارکنان نظام سلامت به دلیل مواجهه با استرس های فیزیکی و روانی در معرض فرسودگی می باشند. این مطالعه با هدف تعیین میزان فرسودگی شغلی بهورزان و بررسی ارتباط خصوصیات جمعیت شناختی با آن انجام گرفت . روش بررسی: این پژوهش توصیفی-تحلیلی، بر روی همه بهورزان شهرستان کوهرنگ ( 81 نفر) در آبانماه سال 1389 انجام شد . ابزار گردآوری داده ها پرسشنامه­ای شامل اطلاعات جمعیت شناختی و پرسشنامه فرسودگی شغلی مازلاک ( MBI ) بود. پرسشنامه توسط بهورزان تکمیل و داده­ها با استفاده از آزمون های آماری ANOVA ، ضریب همبستگی اسپیرمن و آزمون تی مستقل تحلیل گردید. یافته ها: از نظر فراوانی، کاهش موفقیت فردی زیاد ( 5/24 ) ، خستگی عاطفی زیاد ( 6/4 ) و مسخ شخصیت زیاد ( 7/2 ) ، به ترتیب از بیشترین فراوانی و از نظر شدت، خستگی عاطفی شدید ( 7/6 ) و مسخ شخصیت شدید ( 3/1 ) ، به ترتیب از بیشترین شدت برخوردار بودند. هیچ یک از بهورزان کاهش شدید موفقیت فردی را گزارش ننمود. میزان خستگی عاطفی با مسخ شخصیت و میزان کاهش موفقیت فردی با خستگی عاطفی رابطه معنی داری داشت (001/0 > P ) . بین جنس، سن، وضعیت تأهل، سابقه کار، نوع استخدام و میزان تحصیلات بهورزان و فرسودگی رابطه معنی داری دیده نشد. نتیجه گیری: این مطالعه نشان داد که فراوانی و شدت فرسودگی شغلی در بهورزان شهرستان کوهرنگ پایین است که از دلایل آن می توان به موقعیت اجتماعی مناسب، نزدیکی محل کار و زندگی، درآمد متناسب با حجم کار و تحصیلات، امنیت شغلی، سطح توقع پایین و شرایط آب و هوایی و فرهنگی منطقه اشاره کر

Crude oil biodegradation using isolated bacteria from oil polluted soil

Contamination due to the spillage of petroleum or petroleum-derived hydrocarbons on different ecosystems has become critical issues to environment and living things. The use of native bacteria as an environmental friendly treatment of hydrocarbons pollution is very promising. The objective of the study is to identify the native hydrocarbon-degraders isolated from oil refinery. Bacteria from crude oil were isolated and cultured in enrichment media. The isolated strains were then cultured in different oil concentration. The isolated bacterial strains were Gram-stained and further identified via 16S rRNA sequencing. The resultant sequences were then aligned with the available online database for identification of the bacteria. The isolated bacteria belonged to families of Pseudomonadaceae and Moraxellaceae (Acinetobacter genus). The bacteria show high degradation of hydrocarbon and can be used to remediate polluted soils in tropical environment

Impact of introducing electronic acute kidney injury alerts in primary care

Background: Acute kidney injury (AKI) is associated with decreased survival, future risk of chronic kidney disease and longer hospital stays. Electronic alerts (e-alerts) for AKI have been introduced in the UK in order to facilitate earlier detection and improve management. The aim of this study was to establish if e-alerts in primary care were acted on by examining timing of repeat creatinine testing.Methods: The National Health Service England Acute Kidney Injury electronic alert algorithm was introduced in April 2015 across both primary and secondary care in NHS Tayside accompanied by a programme of education. Data from a 12-month period (2012) predating introduction of the e-alerts were compared with a 12-month period following implementation of ealerts for AKI. Biochemistry testing following the AKI episode, timing of repeat tests and numbers of patients hospitalized within 7 days of episode were compared between the two time periods.Results: During the 12 months after e-alert introduction, 9781 AKI e-alerts were generated. Of these, 1460 (14.9%) alerts were generated in primary care. Median duration to repeat blood testing for these primary care alerts was 5 days for AKI Stage 1 [interquartile range (IQR) 2-10], 2 days for Stage 2 (IQR 1-5) and 1 day (IQR 0-2) for Stage 3. During 2012 (prior to e-alert implementation) 8812 AKI episodes were identified. Of these, 2650 tests (30.1%) were requested by primary care staff. Median duration to repeat creatinine testing was longer: 55 days (IQR 20-142) for Stage 1, 38 days (IQR 15-128) for Stage 2 was and 53 days (IQR 20-137) for Stage 3. More patients had biochemistry tests repeated within 7 days of AKI onset, pre-alert implementation; 252 (9.5%) versus 857 (58.7%) (P&lt;0.001). Rates of hospitalization within 7 days of AKI increased from 342 (12.9%) pre-implementation to 372 (25.5%) post-implementation (P&lt;0.001).Conclusions: Within primary care, e-alert implementation was associated with higher rates of creatinine monitoring, but also higher rates of hospitalization.</p

Preventive effect of Silybum marianum hydroalcoholic extract on post-surgical intra-abdominal adhesion in rats

Adhesion formation is the commonest complication of abdominal surgery. Bearing an anti-oxidant activity, Silybum marianum may reduce adhesion formation. This study was an endeavor to shed light on the effect of Silybum marianum on intra-abdominal adhesions. Materials and Methods: In this experimental study, 30 rats were randomly assigned to three groups: treated by 1% and 5% concentrations of the S. marianum extract (groups A and B) and distillated water (group C). After laparotomy, three longitudinal and transverse incisions (2 cm in length) were made on the right wall of the abdomen and a 2×2 piece was removed from peritoneal surface on the left side of the abdominal wall. In groups A, B and C, 3 mL of 1% and 5% of S. marianum extract or distillated water were administered into abdominal cavity of the rats, respectively. After 14 days, adhesion degrees were determined according to the number of adhesion bands (Canbaz scale). Data analysis was performed through SPSS 16 using Kruskal-Wallis and Mann-Whitney tests. Results: There was a significant difference in adhesion formation among the groups (P=0.023). Adhesion degree in groups A and B were significantly lower than the control group (P<0.05). Conclusion: S. marianum extract supported a preventive effect on intra-abdominal adhesion in rats, which gives rise to the evidence that it may be similarly effective for human cases. Throughout further clinical studies, this plant and its derived compounds might be applied in the treatment of such complications subsequent to abdominal surgeries

Local Skin Inflammation in Cutaneous Leishmaniasis as a Source of Variable Pharmacokinetics and Therapeutic Efficacy of Liposomal Amphotericin B.

Disfiguring skin lesions caused by several species of the Leishmania parasite characterize cutaneous leishmaniasis (CL). Successful treatment of CL with intravenous (i.v.) liposomal amphotericin B (LAmB) relies on the presence of adequate antibiotic concentrations at the dermal site of infection within the inflamed skin. Here, we have investigated the impact of the local skin inflammation on the pharmacokinetics (PK) and efficacy of LAmB in two murine models of localized CL (Leishmania major and Leishmania mexicana) at three different stages of disease (papule, initial nodule, and established nodule). Twenty-four hours after the administration of one 25 mg/kg of body weight LAmB (i.v.) dose to infected BALB/c mice (n = 5), drug accumulation in the skin was found to be dependent on the causative parasite species (L. major > L. mexicana) and the disease stage (papule > initial nodule > established nodule > healthy skin). Elevated tissue drug levels were associated with increased vascular permeability (Evans blue assay) and macrophage infiltration (histomorphometry) in the infected skin, two pathophysiological parameters linked to tissue inflammation. After identical treatment of CL in the two models with 5 × 25 mg/kg LAmB (i.v.), intralesional drug concentrations and reductions in lesion size and parasite load (quantitative PCR [qPCR]) were all ≥2-fold higher for L. major than for L. mexicana In conclusion, drug penetration of LAmB into CL skin lesions could depend on the disease stage and the causative Leishmania species due to the influence of local tissue inflammation

Effect of Different Tillage Methods on Soil Physical Properties, Quantitative and Qualitative Yield of Two Forage Maize Cultivars

One of the factors affecting the physical properties of soil and crops is tillage systems. The experiment was conducted in summer 2012 at the research farm of Islamic azad university. This study was performed by experiment a split plot in a randomized complete block design with three replications. The main factors in this study, four different tillage methods as a main factors and  sub factors includes two maize varieties, including single cross 704 and maxima were considered. Also for soil physical properties statistical analysis, randomized complete block design was used. based on the results? different tillage methods on soil physical properties and yield of plants showed significant differences at 1%. Most of the yield was related to corn single cross 704 and twice of disc tillage in depth of 15-10 cm, with 88/18 tons per hectare. The greatest amount of soluble sugars and protein was obtained from corn single cross 704 with cultivator with blade and light disk with depth of 8 to 10 cm. thus it can be concluded that reduced tillage methods in dry and warm regions through Improve soil structure and retain moisture, resulting the yield of quantitative and qualitative of diffrent agricultural products will Increase. Keywords: soil, corn, physical properties,  tillage methods, quantitative and qualitative yield

Flexibility from local resources: Congestion management in distribution grids and carbon emission reductions

Flexibility from local energy systems has been discussed as a facilitator for the transition towards a more carbon-neutral energy system. Two use cases of this flexibility are congestion management in electricity distribution networks, and an individual-driven reduction of carbon footprints. However, for taping into this flexibility, effective incentive mechanisms and operation planning are essential. This licentiate thesis aims to provide new insights into two areas: 1) the design of market-based incentive mechanisms for congestion management in distribution grids, and 2) the operation planning of local flexible asset owners for reducing their carbon emission footprints.The first area focuses on challenges, design, and evaluation of local flexibility markets (LFMs) for congestion management in distribution grids. The utilized methods include literature review, field studies, scenario planning methods, and demonstration and simulation experiments.Results for identifying the challenges show that the most impactful and uncertain factors are the willingness and ability of end-users to participate in LFMs, and regulatory incentives for distribution system operators (DSOs). Moreover, five challenges are identified for LFM design including low market liquidity, reliability concerns, baselines, forecast errors at low aggregation levels, and the high cost of sub-meter measurements.An LFM design is proposed to address the challenges. The design is a triple horizon market structure including reservation, activation, and adjustment horizons which can support decision making of market participants and improve market liquidity and reliability. Adapted capacity-limitation products are proposed that are calculated based on net-load and subscribed connection capacity of end-users. The products can reduce conflict of interests, and administrative and sub-meter measurement costs related to delivery validation and baselines. Moreover, probabilistic approaches for calculating the cost and value of the products are proposed that can reduce the potential cost of forecast errors for market participants while providing insights on how the utility and cost of the products can be calculated.Evaluating the proposed design is an ongoing work utilizing simulations and real-life demonstrations. The most suitable congestion management solution can vary depending on the context and test-system. Therefore, the evaluation should include comparing the design with other congestion management solutions such as power tariffs. A comparison toolbox is proposed to be used by researchers and DSOs including a qualitative comparison framework and a reusable modeling platform for the quantitative comparison. Four cases are quantitatively compared using the toolbox on a sub-area of Chalmers campus testbed: i) LFM+PT+ET (i.e., considering the LFM, power tariff (PT), and energy cost (ET) simultaneously), ii) LFM+ET, iii) PT+ET, and iv) ET. The most recent results show that case (i), has the lowest number of congested hours. Moreover, congestions due to rebound effects from activating the LFM are observed. The comparison of cases (i) and (ii) suggests that enforcing power tariffs besides the LFM can reduce the rebound effects.The second area utilizes a multi-objective optimization model for identifying CO2 emission abatement strategies and their cost for Chalmers testbed local multi-energy system. The results of the case study show that the carbon emission footprint of the local system can be reduced by 20.8% with a 2.2% increase in the cost. The operation strategies for this purpose include more usage of biomass boilers in heat production, substitution of district heating and absorption chillers with heat pumps, and higher utilization of storage. The cost of the strategies ranged from 36.6-100.2 €/tCO2.This thesis can benefit system operators, flexibility asset owners, policy makers, and researchers dealing with local flexibility resources by offering insights into the challenges and proposing solutions and toolboxes for implementation and evaluation

Water Dynamics and the Effect of Static and Alternating Electric Fields

Having a net dipole moment, water molecules tend to align with an external electric field. The re-orientation of water molecules to align with the field direction can result in structural and dynamic changes in liquid water. Studying these changes can help us to understand the role of an E-field in many biological systems, chemical reactions, and many technological advancements. In short, the application of static electric fields causes molecules to stay aligned with the field, so, fewer hydrogen bonds break, and molecules have slower dynamics. This type of field can be used when the mobility of water molecules needs to be reduced, like in electroporation. Alternating electric fields, on the other hand, cause continuous re-orientation of dipole moments, which results in more H bond breaking, water is less structured, and molecules have faster motion. Water under static and alternating electric fields have several applications in science and technology. Although many of the interesting usages of the application of electric fields to water happen at surfaces, the response of hydrogen bonding of water molecules to an E-field is still not fully understood even in bulk. For instance, the rate of hydrogen bond breaking, the re-orientation of water molecules, and the random walk of water molecules under the restrictions of the static electric field have not been thoroughly assessed. The static electric field limits the re-orientation of water molecules, but the translation reduces at the same time, this is clear evidence of roto-translational coupling, and the static electric field is a great groundwork for studying this coupling which is generated by the hydrogen bonds. For studying the effects of an E-field on H-bonding dynamics in depth, we need a model of hydrogen bonding. There are a few models for dynamics of H-bonding and reorientation of water molecules, including Luzar and Chandler model, published in 1996, and the Laage and Hynes jump model, published in 2006, which are described in the introduction chapter. The two models are related but have different perspectives, so it would be very interesting to look for a more general framework of hydrogen bonding by combining these two models, with the help of the influence of external electric fields. We also explain the relation of the random walk diffusion of water molecules and the hydrogen bonding. Since the external electric field can change the dipole moment of water molecules, for a more realistic picture, we need do the simulations with sophisticated polarizable water models to obtain a better estimate of the behavior of experimental water in an electric field. In this thesis, we introduce our generalized hydrogen bond framework; then we assess this framework, as well as other static and dynamic properties of water under static and alternating electric fields