A system dynamics analysis of policies to relieve an urban traffic congestion problem

In the last decade, the continual growth of air transport has resulted in overwhelming traffic congestion in most international airport access roads. This problem is a bottleneck in the development of airports which is regarded as a vital contributor to the economic sustainability of their respective cities. Many studies have been done to relieve the problem of congestion in access roads to airports. However, few of these studies have investigated the implications of these strategies on the different stakeholders in the system. In this study, a System Dynamics model is formulated to provide an understanding of some of the wider consequences of congestion-mitigating strategies in a system comprising airport access for a hypothetical city. This System Dynamics modelling approach offers an assessment platform for policy makers to study the short and long term system behaviour resulting from congestion-mitigation strategies. In particular, the implication of these strategies on the taxi industry livelihood is investigated, which besides the people involved in the industry, makes a significant contribution to an airport's business. The model is composed of three sectors: passengers and travel demand, taxis and private cars, and train. It deals with the congestion level in the road, the growth of passengers, investment in taxis, and the service availability of taxis. Simulations are performed under four policy scenarios aimed at alleviating congestion. The results indicated that, all policy interventions will have some undesirable effects on the taxi industry in terms of reduced profit and loss of jobs, each having a different level of impact. In addition, it was found that the timing of policy interventions has a significant effect on the magnitude of those outcomes. An earlier policy intervention to tackle the congestion leads not only to better conditions for the road in terms of traffic flow, but also less unfavourable effects on the livelihood of taxi drivers and operators. Accordingly, careful attention should be paid to the particular timing of policies and the timing of their implementation. The sensitivity analysis suggests that most parameters are insensitive to variations in parameters, except for one parameter; changes in this parameter had a big impact on the supply and demand for taxis and this in turn has a considerable impact on the viability of the taxi industry. The proper controlling of this variable will allow the amplitude of a shortage or surplus of taxis to be minimized. This thesis focused on certain socio-economic aspects of a transportation system and yielded insights into some aspects of the system which usually is neglected in solving transportation problems. It is hoped that the insights gained by the simulation results will lead to further understanding by decision makers about some of the wider implications of their proposals in solving transportation problems. Finally, the model in this study demonstrates the ability of System Thinking and System Dynamics methodology in the analysis of the dynamic behaviour of socio-economic systems which include complexity and multiple feedbacks

Comparison of Stochastic Methods for the Variability Assessment of Technology Parameters

This paper provides and compares two alternative solutions for the simulation of cables and interconnects with the inclusion of the effects of parameter uncertainties, namely the Polynomial Chaos (PC) method and the Response Surface Modeling (RSM). The problem formulation applies to the telegraphers equations with stochastic coefficients. According to PC, the solution requires an expansion of the unknown parameters in terms of orthogonal polynomials of random variables. On the contrary, RSM is based on a least-square polynomial fitting of the system response. The proposed methods offer accuracy and improved efficiency in computing the parameter variability effects on system responses with respect to the conventional Monte Carlo approach. These approaches are validated by means of the application to the stochastic analysis of a commercial multiconductor flat cable. This analysis allows us to highlight the respective advantages and disadvantages of the presented method

Sustainable Use of Biomass Boiler Ash as a Reinforcement Filler for Polyamide 6 Composite

The use of biomass combustion ash as a reinforcing filler has taken the attention in recent years to reduce the overall production cost and increase the mechanical properties of plastics. This study evaluates the effect of biomass boilers ash (BBA) as a reinforcing filler on polyamide 6 composites (PA6). The chemical composition and thermal stability of BBA were analyzed by X-ray fluorescence (XRF), Thermogravimetric analysis (TGA), and Differential thermal analysis (DTA) thermographs. Test samples were prepared by varying the ash content (2.5%, 5%, 7.5%, and 10%), and also samples were prepared without adding ash as a control. Moreover, surface modification was carried out by using N-2 (Aminoethyl) 3-aminopropyl triethoxy diamino-silane as a possible coupling agent for BBA  and it was tested by varying the coupling agent concentration (0.5%, 1%, and 2%) by dry process and the samples were prepared by extrusion and injection molding processes. Comparative analysis of the degree of crystallinity, mechanical properties including tensile, flexural, and thermal properties were tested. The highest degree of crystallinity was obtained with 7.5% BBA-filled composites. The addition of 2% surface-modified BBA (SBBA) filled composites (PA6 / 10% Ash 2% CA) showed an increase of tensile strength and elongation at break than the 10% unmodified BBA (UBBA) (PA6/ 10% Ash) filled composites. Stress at peak and bending modulus values in the flexural test data were increased up to 10%. But it was significantly reduced with the increasing of modifying agent concentration due to the increment of stiffness of the composite

Effects of ultrasound irradiation on the release profile of 5-fluorouracil from magnetic polylactic co-glycolic acid nanocapsules

Background: Drug nano-carriers are one of the most important tools for targeted cancer therapy so that undesired side effects of chemotherapy drugs are minimized. In this area, the use of ultrasound can be helpful in controlling drug release from nanoparticles to achieve higher treatment efficiency. Objective: Here, we studies the effects of ultrasound irradiation on the release profile of 5-fluorouracil (5-Fu) loaded magnetic poly lactic co-glycolic acid (PLGA) nanocapsules. Methods: 5-Fu loaded magnetic PLGA nanocapsules were synthesized by multiple emulsification method. Particle size was measured by dynamic light scattering (DLS) and transmission electron microscope (TEM). The pattern of drug release was assessed with and without 3 MHz ultrasound waves at intensities of 0.3, 0.5 and 1 w/ cm2 for exposure time of 5 and 10 min in phosphate-buffered saline (PBS). Results: The size of nanoparticles was about 70 nm. Electron microscope images revealed the spherical shape of nanoparticles. The results demonstrated that the intensity and exposure time of ultrasound irradiation have significant effects on the profile of drug release from nanoparticles. Conclusion: It may be concluded that the application of ultrasound to control the release profile of drug loaded nanocapsules would be a promising method to develop a controlled drug delivery strategy in cancer therapy. © 2016 Shiraz University of Medical Sciences. All rights reserved

TEHRAN AIR POLLUTION MODELING USING LONG-SHORT TERM MEMORY ALGORITHM: AN UNCERTAINTY ANALYSIS

Air pollution is a major environmental issue in urban areas, and accurate forecasting of particles 10 μm or smaller (PM10) level is essential for smart public health policies and environmental management in Tehran, Iran. In this study, we evaluated the performance and uncertainty of long short-term memory (LSTM) model, along with two spatial interpolation methods including ordinary kriging (OK) and inverse distance weighting (IDW) for mapping the forecasted daily air pollution in Tehran. We used root mean square error (RMSE) and mean square error (MSE) to evaluate the prediction power of the LSTM model. In addition, prediction intervals (PIs), and Mean and standard deviation (STD) were employed to assess the uncertainty of the process. For this research, the air pollution data in 19 Tehran air pollution monitoring stations and temperature, humidity, wind speed and direction as influential factors were taken into account. The results showed that the OK had better RMSE and STD in the test (32.48 ± 9.8 μg/m3) and predicted data (56.6 ± 13.3 μg/m3) compared with those of the IDW in the test (47.7 ± 22.43 μg/m3) and predicted set (62.18 ± 26.1 μg/m3). However, in PIs, IDW ([0, 0.7] μg/m3) compared with the OK ([0, 0.5] μg/m3) had better performance. The LSTM model achieved in the predicted values an RMSE of 8.6 μg/m3 and a standard deviation of 9.8 μg/m3 and PIs between [2.7 ± 4.8, 14.9 ± 15] μg/m3

Investigation of itch in Parkinson disease

Introduction: Sensory abnormalities (eg, pain) are common in Parkinson disease (PD) with a negative impact on quality of life. As itch is less studied in PD, and pain and itch partially share sensory pathways, we designed this study to identify the occurrence and pattern of spontaneous itch, and responsiveness to a surrogate itch model in PD. Methods: The study protocol was approved (N-20180079) and PD patients and their best matched controls were recruited. A questionnaire was used to collect general information on itch. Sensory alterations were determined by subjective ratings and mechanical sensitivity threshold before and after a standard histamine-dependent itch model on forearms. Itch and pain intensities were rated on visual and numerical rating scales, respectively. Dispersion of itch was drawn on arm charts. Presence and area of alloknesis and hyperknesis were determined. Group comparisons were performed in SPSS with a significant level of 0.05. Descriptive statistic was used for questionnaire’s analysis. Results:Patients(n=20;68.10±7.91y,F/Mratio:8/12)andcontrols(n=20;67.35±7.65y,F/Mratio:8/12)wereexamined.PD patients rated less physical and emotional descriptors, except for the stinging (P = 0.028). No difference was found between the groups in histamine-provoked itch intensity (P = 0.799) or the itchy area. A significantly larger area of hyperknesis was found in PD (P = 0.011), but not for the area of alloknesis (P = 0.221). Sex-related responses yielded only a tendency toward higher responses in female patients. Discussion:PDdoesnotseemtoinfluenceperceptionofitch,neitherspontaneousnorevokeditch,exceptforhyperknesisarea,which was found significantly larger in PD patients following the application of histamine. This finding proposes a potential alteration in central processing of itch that needs further investigation and whether and how it is affected by, for example, PD pathogenesis

Use of sonic tomography to detect and quantify wood decay in living trees.

Premise of the studyField methodology and image analysis protocols using acoustic tomography were developed and evaluated as a tool to estimate the amount of internal decay and damage of living trees, with special attention to tropical rainforest trees with irregular trunk shapes.Methods and resultsLiving trunks of a diversity of tree species in tropical rainforests in the Republic of Panama were scanned using an Argus Electronic PiCUS 3 Sonic Tomograph and evaluated for the amount and patterns of internal decay. A protocol using ImageJ analysis software was used to quantify the proportions of intact and compromised wood. The protocols provide replicable estimates of internal decay and cavities for trees of varying shapes, wood density, and bark thickness.ConclusionsSonic tomography, coupled with image analysis, provides an efficient, noninvasive approach to evaluate decay patterns and structural integrity of even irregularly shaped living trees

Multiple brain developmental venous anomalies as a marker for constitutional mismatch repair deficiency syndrome

The occurrence of multiple developmental venous anomalies in this study of 10 patients with constitutional mismatch repair deficiency syndrome (CMMRD) suggests that developmental venous anomalies may be a characteristic of this syndrome that has not been previously described. A retrospective descriptive analysis of brain MR imaging studies from 3 families with CMMRD was performed. Analysis included the number of developmental venous anomalies, location, draining vessels, and associated vascular anomalies (for instance, cavernomas) with clinical correlation of symptoms and tumors. CMMRD is a cancer-predisposition syndrome with very high penetrance and most reported individuals are affected during childhoodInternational Biallelic Mismatch Repair Deficiency ConsortiumMeagan’s Walk, the CIHR Joint Canada- Israel Health Research Program, and an American Association for Cancer Research Stand Up 2 Cancer Catalyst TM Research Gran

Design and Validation of Synchronous QCT Calibration Phantom: Practical Methodology

Introduction: Quantitative computed tomography (QCT) can supplement dual x-ray absorptiometry by enabling geometric and compartmental bone assessments. Whole-body spiral CT scanners are widely available and require a short scanning time of seconds, in contrast to peripheral QCT scanners, which require several minutes of scanning time. This study designed and evaluated the accuracy and precision of a homemade QCT calibration phantom using a whole-body spiral CT scanner. Materials and Methods: The QCT calibration phantom consisted of K 2 HPO 4 solutions as reference. The reference material with various concentrations of 0, 50, 100, 200, 400, 1000, and 1200 mg/cc of K 2 HPO 4 in water were used. For designing the phantom, we used the ABAQUS software. Results: The phantoms were used for performance assessment of QCT method through measurement of accuracy and precision errors, which were generally less than 5.1 for different concentrations. The correlation between CT numbers and concentration were close to one (R 2 = 0.99). Discussion: Because whole-body spiral CT scanners allow central bone densitometry, evaluating the accuracy and precision for the easy to use calibration phantom may improve the QCT bone densitometry test. Conclusion: This study provides practical directions for applying a homemade calibration phantom for bone mineral density quantification in QCT technique. © 201