Modelling of secondary sedimentation under wet-weather and filamentous bulking conditions

Secondary settling tanks (SSTs) are the most hydraulically sensitive unit operations in wastewater treatment plants (WWTPs). Performance of SSTs influences the solids inventory in the activated sludge unit and consequently impacts the biological treatment efficiency. Moreover, SSTs limit the maximum permissible flow rate entering the WWTPs during wet-weather conditions. Therefore, modelling the dynamics in the SSTs is an essential part of integrated sewer- WWTP modelling for the purpose of optimization and control, specifically under wet-weather conditions. One-dimensional (1-D) SST models with first-order type equations are widely used among researches and practitioners for dynamic WWTP simulations. Several drawbacks of the first-order models have however been reported in the literature, which have led to the development of more advanced second-order 1-D SST models. Unfortunately, the second-order models have not yet found their way into practice. This thesis aims at encouraging a broader application of secondorder 1-D SST models by assessing their significance for WWTP modelling by means of global sensitivity analysis (GSA). Moreover, laboratory and numerical (computational fluid dynamics, CFD) tools were developed for the identification and calibration of the settling sub-model in the SST models. The developed CFD tool is a potential tool for the development of a more mechanistic based flow (and design) dependent hydraulic sub-model in the second-order 1-D SST. In this thesis, a rigorous comparative evaluation of the first- and second-order SST models in WWTP modelling was performed by means of GSA. In the first GSA study using the Benchmark Simulation Model No. 2 with first- and second-order SST models, the settling parameters were included in the sensitivity analysis. Interestingly, the settling parameters were found to be among the most influential parameters for predicting the WWTP performance in terms of biogas production and quality of treated water. Importantly, it was observed that the choice of 1-D SST type model influences the sensitivitymeasures of the parameters and consequently result in different parameter sub-sets for the calibration of WWTP models. Furthermore, the limitations of first-order SST models with relevance to the calibration of WWTP models were discussed. In the second GSA study of this thesis, the aim was to supplement the protocol recently published by the International Water Association on good modelling practice for activated sludge systems with practical findings on the calibration of 1-D SST models for dynamic WWTP simulations under ideal and non-ideal flow (dry- or wet-weather) and settling (good settling and/or bulking) boundary conditions. The Benchmark simulation model No. 1 in combination with first- and second-order 1-D SST models was used. An assessment was performed on the sensitivity of WWTP model outputs to uncertainties intrinsic to 1-D SST model structures and parameters under different boundary conditions imposed to WWTP simulation models. Further, the relative sensitivity to these uncertainties indicated potential parameter subsets for WWTP model calibration and the optimal choice of 1-D settling model structure under the different boundary conditions. Importantly, the hydraulic parameters in the second-order 1-D SST model were found significant under dynamic wet-weather flow conditions. The results of this study illustrated the advantages of second-order 1-D SST models for dynamics WWTP simulations under wider flow and bulking conditions, and furthermore, highlighted the necessity of developing a more mechanistic based flow-dependent hydraulic sub-model in second-order 1-D SST models in the future. A significant part of the thesis was dedicated to the development of a CFD model of a circular conical SST with the open source OpenFOAM CFD toolbox. The focus was mainly on identifying the settling and rheology submodels using data obtained from laboratory batch experiments. A simple, novel settling column experimental set-up was developed to evaluate the accuracy of the state-of-the-art settling velocity models. For calibration the Bayesian optimization method DREAM(ZS) was used. Consequently, a new settling velocity model, including hindered, transient and compression settling, was developed. In addition, a rheology model of activated sludge was selected and calibrated to high quality rheological measurements from the optimized batch experiments. New correlations between rheology model parameters and sludge concentration were identified. A 2-D axisymmetric CFD model of a circular SST containing the new settling velocity and rheology sub-models were validated with full-scale measurements. Finally, it was shown that the representation of compression settling in the CFD model greatly influences the prediction of sludge distribution in the SSTs. The validated CFD model was further used in the last study of this thesis to model the impact of filamentous bulking on the sludge distribution and transport in SSTs by calibrating the rheology and settling sub-models to measurements ofsludge with high and low filamentous bacteria content

A review of English for medical purposes for Iranian EFL learners

Considering the significant role that English language plays in medical education, not only for learning purposes and seeking knowledge but also for presenting research activities in international fields, English learning and teaching programs are worth noting more accurately. The aim of this review paper is to present some of the basic concepts regarding teaching English for medical purposes to English- as-a-foreign-language students. Some of these influencing factors in the academic field could be named as the necessity of students’ need assessment, content evaluation, promotion of teachers’ knowledge and renewing medical English curricula every now and then as needed. Ultimately, several suggestions are presented which could be utilized by instructors, text developers and educational authorities for the betterment of medical English programs

Seasonal variation of Guillain-Barré syndrome in Iranian patients: a retrospective study

Background: It seems that the incidence of Guillain-Barré syndrome (GBS) has seasonal trends depending on weather as well as environmental and demographic factors such as upper respiratory tract infection (URI). The aim of this study was to evaluate seasonality of GBS and its electrophysiological subtypes. Methods: In this cross-sectional study, the records of all admitted patients to all wards of Dr. Shariati Hospital from March 2009 to March 2019 according to ICD-10 codes for GBS and other similar neuropathies were investigated and 87 patients were registered based on fulfillment of Brighton criteria and symptom onset during the recent 4 weeks. Statistical analysis was performed by IBM SPSS version 20. A p-value < 0.05 was considered statistically significant. Results: Most of the patients (63.2%, n=55) were men. The mean age of them was 49.1±19.2 years, and 41.3% (n=36) and 10.3% (n=9) participants had recent URI and gastrointestinal infection, respectively. The frequency of GBS in different seasons was 35.6% (n=31) patients in the winter, 27.6% (n=24) in the autumn, 19.6% (n=17) in the spring, and 17.2% (n=15) in the summer. The most frequent electrophysiological subtype was acute inflammatory demyelinating polyneuropathy (AIDP) in all seasons. The most common GBS disability score was 1. Conclusion: The highest and the lowest occurrence was seen in the winter and summer, respectively. AIDP was the most common electrophysiological subtype in all seasons. More studies are suggested to evaluate other aspects of GBS on more details

Necrotizing fasciitis of the extremities: a prospective study

Necrotizing fasciitis is a rapidly progressive infection and is a necrosis of the fascia and surrounding tissues. Despite recent advances in its management, outcomes have not improved and mortality rate is still high. Between September 2007 and August 2009, we prospectively studied twenty-four histopathologically proven necrotizing fasciitis patients to assess the prognostic factors that indicate the outcome. Mortality rate was 20.8%. Twelve patients (50%) improved, while seven patients (29.2%) were complicated by limb loss. Mortality rates related to upper and lower limb involvement were similar (20% vs. 22.2%). The rates of gangrene and amputation in patients with diabetes mellitus were significantly higher than other comorbidities. Patients with gram-positive infections had significantly lower rates of amputation (15.4% vs. 54.5%, P = 0.04). Mean band cell count and serum potassium level were significantly higher in the nonsurvivors same as leukocyte count in the patients with gangrene, while serum sodium level was significantly lower in nonsurvivors. We conclude that hyponatremia, hyperkalemia, and increased band cells in the peripheral blood of patients may be useful parameters in distinguishing life-threatening necrotizing fasciitis; hence, we recommended lower threshold to amputation during surgery for this group of patients

Proposing a Conceptual Model for Teacher Expertise in ELT

Interest in expertise studies has been shown from the beginning of 21st century so far in quite many fields including art, music, chess, medical sciences, etc. Just recently, applied linguistics has joint this new wave of research and this was an inspiration for conducting the present research. Since the early twenty-first century, expertise studies have been undertaken in a large number of domains. Applied linguistics is relatively a newcomer to the list which makes any study aiming to cast light on some aspect of expertise in this domain worth considering. In the present study, a model is proposed for the construct of teaching expertise in ELT comprised of 8 interrelated factors. Based on a perusal of previous research on expertise in education and the thought patterns and behavior of exemplary teachers of English language these factors were extracted. The direct or indirect effect of each factor on the latent variable, teaching expertise, is indicated in the model. For further content validation, 20 specialists of the field were interviewed.  These specialists included university professors of applied linguistics, teacher educators, teacher trainers at the private sector, mentor teachers and experienced teachers. The 8 factors which were extracted from prior research and interviewees’ remarks include: teacher’s language proficiency, pedagogical content knowledge, social recognition, cognitive skills, experience, professional development, contextual knowledge, and learner-centered teaching. These are perceived to be the key constituents of teaching expertise in ELT. This model is aimed to be later used as a basis for developing an instrument for operationalizing the construct of teacher expertise in ELT

Insights into the Impacts of Synthesis Parameters on Lignin-based Activated Carbon and Its Application for: Methylene Blue Adsorption

In the current research, lignin was successfully extracted from industrial waste Kraft black liquor using the acid precipitation method. In the following step, powdered carbon was synthesized through the H3PO4-chemical activation method. The effects of synthesis parameters, including activation temperature (T) within the range of 400-600 ⁰C and two H3PO4/Lignin mass ratios (R) of 2 and 3 on activated carbon (AC) structure, were investigated. The physical and morphological properties of the ACs were obtained through BET, SEM, and FTIR analyses. The potential application of ACs was studied by measuring their adsorption capacity in the adsorption process of Methylene blue (MB) from an aqueous solution. The sensitized AC at R=2, and T= 500 ⁰C (AC-2-500) showed the highest specific surface area (1573.31 m2/g) and the pore volume (0.89 cm3/g), as well as the highest adsorption capacity of MB. This adsorbent was applied in the equilibrium adsorption experiments and kinetic description. The results from kinetic experiments and adsorption isotherms indicated that the pseudo-first-order model and Langmuir model were in correspondence with the experimental data most. The maximum adsorption capacity was 188 mg/g. The study proved there is a high potential for the conversion of black liquor to greatly porous Lignin-based adsorbents. Moreover, the considerable maximum adsorption capacity suggested a significant potential of Lignin-based AC for wastewater treatment

The Effect of Rosa damascena on Children’s Enuresis: A Randomized Pilot Study

Background and Aim: Enuresis is one of the common problems among children. The present pilot study was conducted to investigate the effect of Rosa damascene on nocturnal enuresis in children. Materials and Methods: A randomized pilot study was performed from April 2017 to March 2018. The study participants were 40 children aged between 5-12 years with nocturnal enuresis. They were randomly divided to intervention and control groups using block randomization. The intervention group received R. damascena petals under the brand name Gole-Ghand (Barij- essence, Iran) as 5 cc orally, every 8 hours for one month. The control group received desmopressin as nasal spray (Sina Darou, Iran) 1-2 puffs for one month (maximum 20 mg daily). The primary outcome was complete or partial improvement in enuresis. The secondary outcome was frequency of side effects in patients. Results: Twenty-two out of 39 patients 22 (56.4%) were male and 17 patients (43.6%) were female with the average age of 7.3±1.86 years. There was no noticeable distinction between the groups in age, sex, urbanity, history of treatment, and primary or secondary enuresis (p>0.05). Complete improvement was observed in 14 patients (70%) in the control group. Partial improvement was observed in four patients (20%) in the control group and in six patients (31.5%) in the intervention group (p:0.001). No side effect was reported during the study in the intervention group. Conclusion: Based on the results of this pilot study, the use of R. damascena may lead to partial improvement against enuresis in some children. Further studies are required to evaluate this hypothesis