17 research outputs found
Optimization of pavement preservation strategy considering cost and environmental impacts
No full textRoad maintenance is crucial for the purpose of retarding deterioration of pavement, which is a complex and continuous process due to the interaction of heavy traffic, environmental condition, and material aging. The combination of increased traffic and lack of appropriate maintenance causes a higher rate of degeneration in the roads. Transportation agencies need to develop a system for disseminating limited funds and decide the timing to conduct maintenance and repairs. In order to establish a cost-effective budget and achieve the optimum utilization of available resources, the agency needs to decide which maintenance treatment to use and where and when to apply it. The primary objective of this dissertation is to develop network-level pavement preservation decisions considering multiple objectives of cost and environmental impacts. This research will produce multi-objective optimization models designed to provide highway agencies with means of making road maintenance decisions among different concerns. Therefore, this study developed regression models of CO2 emissions for four vehicle types to quantify the environmental impact at the use stage. The simulated constraint boundary method (SCBM) was used as a tool to find Pareto optimal solutions for the pavement multi-objective optimization problem of minimizing agency costs and minimizing CO2 emissions by minimizing average network IRI value. This method is based on solving one objective and converting the other objective to constraint, so the decision makers need to decide first which objective should be considered as the primary objective (the objective that deserves the most attention among the competing objectives). The results show that the crack seal is still the most dominant preservation treatments compared to thin overlay although it has less effect on the reduction of IRI than the thin overlay treatment. So, the objective of minimizing agency cost controls the optimization results although the minimization of CO2 emissions was considered in the optimization process. Another method that was used in this research to achieve both objectives of minimizing agency costs and emissions is the Weighted Sum method. Weighted sum method is based on converting the two objectives into one single objective by adding both objectives together after multiplying each objective by a weighting factor. The value of weighting factor should be considerable relative to other weighting factors and comparative to its corresponding objective function. The results for the distribution of pavement preservation treatments show that less costly preservation treatments were selected for the most segments of the network when the priority of optimization was given to the objective of minimization agency cost. The treatments that have higher effectiveness on pavement condition were selected for the most segments of the network when the objective of minimization CO2 emission is the main objective compared to the other objective.Ph.D.Includes bibliographical referencesby Israa Fadhil Jasim AL-Saad
The V3D socket: Designing a Volume-adjustable, Affordable, 3D printable, Transradial, Prosthetic socket
No full textThe conventional fabrication process of prosthetic sockets is known for being labor-intensive and time-consuming. It takes the user to wait 2-5 weeks to receive the prosthetic socket. In addition, most of the conventional sockets have fixed volumes that do not consider the volume fluctuations that the user experience daily because of muscle activities and comorbid medical conditions. 3D printing has shown promising results in producing lower limb sockets; however, upper limb sockets are overlooked. The goal of this master thesis is to design and fabricate a volume-adjustable, affordable, 3D printable transradial, prosthetic socket. In this research, the V3D (Volume-adjustable, 3D printable) socket has been developed with a material cost of only €30. The socket provides a volume-adjustable closure system around the residual limb, easiness of donning and doffing without skin shearing, full elbow extension, high range of flexion, low weight, and breathability. The socket was designed to be able to withstand a load of 50N that can be applied axially or transversely at the tip of the socket without breakage. The designed socket was 3D printed using the Fused Deposition Modeling (FDM) printing technique, from tough Polylactic Acid (tough PLA). Mechanical and human assessments have been conducted to evaluate the strength, function, and comfort of the developed socket. Results have shown that the socket managed to withstand a load up to 100N that was applied axially and transversely, respectively, without showing any signs of damage. During testing the socket with 5 participants for evaluating its comfort and function, the socket has succeeded to achieve full contact with the residual limbs, while offering volume-adjustability that accommodated the differences in size and properties of the residual limbs among participants. Not only that, but also, the socket succeeded to allow full elbow extension, a range of flexion up to 95°, and donning and doffing in less than 10 seconds without applying any shear forces on the skin. The developed V3D socket has proven the possibility to 3D print reliable sockets using the FDM printing technique with a total labor time of 4 hours per socket, and a total fabrication time of 5 days with a material cost of only €30. In addition, the socket has proved that it can be fitted using a caliper in case 3D scanners are not available. That advantage makes producing the V3D socket feasible in communities that do not have access to 3D scanners. Furthermore, the socket can be parameterized such that users with similar geometry and comparable sizes of residual limbs can fit the same socket, which would make the fabrication process less labor-intensive and less time-consuming as it was aimed for.Mechanical Engineering | BioMechanical Desig
The efficiency of healthcare systems in the Arab countries: a two-stage data envelopment analysis approach
Full text linkPurpose – This study aims at evaluating the technical efficiency (TE) of healthcare systems in the Arab region and exploring the key factors that affect the efficiency performance. Design/methodology/approach – The study applies a two-stage Data Envelopment Analysis (DEA) approach to a sample of 20 Arab countries. In the first stage, a DEA model is used to calculate the TE scores of the examined healthcare systems in 2019 and 2010, following both the output and input orientations of efficiency. In the second stage, a censored Tobit model is estimated to investigate the determinants of healthcare efficiency. Findings – DEA results of 2019 indicate that achievable efficiency gains of the Arab countries range from 0.4% to 16% under the output and input orientations, respectively. Six countries are efficient under both orientations. Although the average efficiency scores of the Arab countries have deteriorated between 2010 and 2019, Djibouti and Sudan had the greatest efficiency improvements between the two years. Bahrain, Mauritania, Morocco and Qatar proved to be efficient in 2010 and 2019 under the two orientations of efficiency and according to the two DEA specifications followed. The Tobit model reveals that corruption and government health expenditure tend to have an adverse impact on healthcare efficiency. Originality/value – The author evaluates healthcare efficiency and healthcare's efficiency determinants in the Arab countries. Regardless Arab countries' diversity, these countries are facing common health challenges, including diminishing role of governments in healthcare financing; increased out-of-pocket healthcare spending; poor healthcare outputs and prevalence of health inequities resulting from weak governance institutions. Comparing the efficiency of healthcare systems between 2010 and 2019 gives insights on the potential impact of the Arab spring uprisings on healthcare efficiency. Moreover, examining the determinants of healthcare efficiency allows for better understanding of how to improve the efficiency of healthcare systems in the region
Extensive Theoretical Studies of the Highly Excited Electronic States with the Experimental Parameters Calculation for the Laser Cooling of CaI Molecule
No full textBy using the multireference configuration interaction method followed by Davidson correction, the electronic structure of the molecule CaI has been investigated. The potential energy curves, the permanent and transition dipole moment curves, and the spectroscopic parameters of 18 electronic states are investigated for these states along with 111 vibrational levels of the four lowest electronic states. The Franck–Condon factors and the radiative lifetime are calculated for the XThe presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Theoretical Studies of the Excited Electronic of the molecule ScLi and its ions ScLi± with a Feasibility Study of Laser Cooling
Full text linkFor the transition-metal lithides ScLi and ScLi±, the adiabatic potential energy and the static and transition dipole moment curves of the low-lying electronic states in the representation 2s+1Ʌ(+/-) have been investigated. The spectroscopic constants, the electronic transition energy with respect to the ground state Te, the internuclear distance Re, the harmonic frequency ωe, the rotational constant Be, the permanent dipole moment µe, and the dissociation energies De have been computed for the bound and excited states. Using the canonical function approach, these calculations have been followed by a rovibrational calculation from which the rovibrational constants Ev, Bv, Dv, and the abscissas of the turning points Rmin and Rmax for the investigated bound states are calculated. A feasibility study of laser cooling of the ScLi and its ions ScLi± has been done. New 62 electronic states have been investigated in the present work for the first time. No useful cooling scheme was found for those molecules.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Corrigendum to "Development of SARS-CoV-2 Inhibitors Using Molecular Docking Study with Different Coronavirus Spike Protein and ACE2” [J Mol Docking. 2021;1(2):1-14]
No full textAuthors have found an error in the previous version (Shamkh, IM, & Pratiwi, D. (2021). Development of SARS-CoV-2 Inhibitors Using Molecular Docking Study with Different Coronavirus Spike Protein and ACE2. Journal of Molecular Docking, 1(1), 1-14. https://doi.org/10.33084/jmd.v1i1.2212), of which Dr. Hanaa S. Omar as supervisor of the research, is not listed as one of the authors. In this note, Dr. Hanaa S. Omar was added as one of the authors, with the status of the corresponding author in the study
A New Ridge – type in the Bell Regression Model
Full text linkIn scenario analysis, collinearity is a big issue in analyzing such relationship as between the response variable and several explanatory variables. As for these difficulties, the linear regression model, often traditionally, offers a range of shrinkage estimators. One such estimator is the ridge estimator. Thus, in order to fit count data with over-dispersion, for the bell regression model, this paper presents an improvement of the new Ridge-type estimator. Judging from the Monte Carlo simulation and the application of the Bell regression model, it was noted that the proposed estimate yields on average a smaller mean squared error than the other candidate estimators
Red biotechnology: A healthy world
Full text linkBiotechnology is an interdisciplinary field of engineering, physics, chemistry and biology. The present era of Biotechnology has reached to a stage of treating killer diseases like cancer, HIV; disorders like diabetes, cardiac diseases and even hereditary disease at the genetic level etc. This review emphasizes the applications of Biotechnology in the medicine field and the basic development of nanomedicine. © 2019 Author(s)
Restricted ride estimator in the Inverse Gaussian regression model
Full text linkThe inverse Gaussian regression (IGR) model is a well-known model in application when the response variable positively skewed. Its parameters are usually estimated using maximum likelihood (ML) method. However, the ML method is very sensitive to multicollinearity. Ridge estimator was proposed in inverse gaussian regression model. A restricted ridge estimator is proposed. Simulation and real data example results demonstrate that the proposed estimator is outperformed ML and inverse Gaussian ridge estimator
Experimental feasibility study of using eco- and user-friendly mechanochemically activated slag/fly ash geopolymer for soil stabilization
Full text linkThis study focuses on the development of eco and user-friendly mechanochemically-activated geopolymeric stabilizers, surpassing the limitations inherent in traditional geopolymerization methods. A comparative analysis was undertaken with conventionally activated geopolymer stabilizers to establish benchmarks for effectiveness in soil stabilization applications. Additionally, the research delves into the impact of granulated blast-furnace slag (GGBS) content on the mechanical and durability properties of stabilized soil samples. In addition, the investigation focuses on the influence of the activation method on soil effectiveness and strength post-exposure to sulfate attack. The durability performance is rigorously assessed through the immersion of specimens in a 1 % magnesium sulfate (MgSO4) solution for 60 and 120 days. The comprehensive evaluation includes visual appearance, mass changes, Ultrasonic Pulse Velocity (UPV), Unconfined Compressive Strength (UCS), and Fourier-Transform Infrared (FTIR) spectra of geopolymer-stabilized soil specimens. The results showed that before the exposure to the MgSO4 solution, the UCS of mechanochemically activated geopolymer (MAG) samples was higher (12–45 %) than that of conventionally activated geopolymer (CAG)-stabilized soil. Furthermore, the strength of the geopolymer-stabilized soil improved by 114 %, 247 %, and 361 %, at 50, 75, and 100 % GGBS content, respectively. On the other hand, after exposure to the MgSO4 solution, the results showed that the mechanochemically activated geopolymer-stabilized soil has better resistance to sulfate erosion than the conventionally activated geopolymer-stabilized soil. The residual UCS for MAG and CAG samples were 93 % and 89 % when exposed to 1 % magnesium sulfate solution for 60 days, whereas they declined to 70 % and 58 %, respectively, after 120 days of immersion. © 2024 The Author
