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A Flexible Reformulation of the Refueling Station Location Problem
Serious environmental and economic problems of using fossil fuels in transportation sections force managers to think of alternative fuels such as hydrogen, ethanol, biodiesel, natural gas, or electricity. Meanwhile, lack of fuel network infrastructures is a major problem, which needs to be investigated considering the number and optimal location of alternative fuel stations. In the literature, two different flow-based demand modeling concepts (the maximum cover and set cover) have been proposed for solving this problem. Because of the huge number of combinations of fuel stations for covering the flow of each path, the models are impractical for the real size problems. In this paper, the flow refueling location model was reformulated and a flexible mixed-integer linear programming model was presented, which was able to obtain an optimal solution much faster than the previous set cover version. The model also could be solved in the maximum cover form in a reasonable time on the large-sized networks.
Journal Article
Hematological Changes in Gas Station Workers
(1) Background: Benzene, toluene, and xylene isomers (BTX) are present in gasoline. Exposure to benzene may lead to the appearance of a series of signs, symptoms, and complications, which are characterized by benzene poisoning, which is an occupational disease. This study evaluated the presence of signs and symptoms related to occupational exposure and whether occupational exposure to BTX is associated with the development of hematological changes. (2) Material and Methods: This cross-sectional epidemiological study included 542 participants, in which 324 were gas station workers (GSWs) and 218 were office workers (OWs) with no occupational exposure to benzene. To characterize the type of exposure (exposed and not exposed), trans,trans-Muconic acid (tt-MA), Hippuric acid (HA), and Methylhippuric acid (MHA) were used as exposure biomarkers. The tt-MA analysis revealed that the GSWs had 0.29 mg/g of urinary creatinine and the OWs had 0.13 mg/g of urinary creatinine. For HA, the GSWs presented 0.49 g/g of creatinine while the OWs presented 0.07. MHA analysis revealed that the GSWs had 1.57 g/g creatinine and the OWs had 0.01 g/g creatinine. Occupation habits and clinical symptoms were collected by questionnaire and blood samples were analyzed for hematological parameters. The persistence of hematological changes was evaluated with three serial blood collections every 15 days followed by laboratory hematological analysis. A descriptive analysis by the Chi-square test method was performed to evaluate the association between occupational exposure to fuels and the occurrence of changes in hematological parameters. (3) Results: In the GSWs, the most described signs and symptoms were somnolence (45.1%), headache (38.3%), dizziness (27.5%), tingling (25.4%), and involuntary movement (25%). Twenty GSWs that presented hematological alterations performed serial collections fifteen days apart. In addition, these workers presented total leukocyte counts above the upper limit and lymphocyte counts close to the lower limit. Leukocytosis and lymphopenia are hematological alterations present in chronic benzene poisoning. (4) Conclusions: The results found an initial change in different hematological parameters routinely used in clinics to evaluate health conditions. These findings reveal the importance of valuing clinical changes, even in the absence of disease, during the health monitoring of gas station workers and other groups that share the same space.
Journal Article
Occupational exposure at petrol stations and red- green colour vision deficiency: a case-control study from Sudan
Background
Occupational exposure to petroleum-derived organic solvents has been associated with acquired colour vision impairment. Evidence from low- and middle-income settings remains limited.
Objective
To examine the association between occupational exposure to benzene/gasoline and red-green colour vision deficiency among petrol station workers in Khartoum State, Sudan.
Methods
An analytical case-control study was conducted (February May 2022) at 19 petrol stations. Adult male participants were classified as cases (red-green colour vision deficiency) or controls (normal colour vision) using Ishihara plates (1999 edition). Exposure status (occupational petrol station work) and covariates were obtained via structured interviews. Visual acuity was assessed using the Landolt C Snellen chart. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated; multivariable logistic regression was used to adjust for age, smoking status, and work duration.
Results
A total of 176 participants (88 cases, 88 controls) were included. Occupational exposure was more frequent among cases than controls (64.8% vs. 47.7%). Exposure was associated with higher odds of red-green colour vision deficiency (adjusted OR ≈ 2.0; 95% CI 1.09–3.66;
p
= 0.02). Visual acuity was largely normal in both groups. Smoking was common but was not independently associated with colour vision deficiency after adjustment (
p
> 0.05).
Conclusions
Occupational exposure at petrol stations was associated with red-green colour vision deficiency. Given the cross-sectional nature of exposure assessment and use of a screening tool for colour vision, findings should be interpreted as associative. Enhanced occupational health surveillance and eye safety practices are warranted.
Journal Article
Sustainable Development in Old Communities in China—Using Redesigned Nucleic Acid Testing Booths for Community-Specific Needs
The sustainable development of urban communities has attracted widespread attention from all sectors. So, the question regarding how to promote sustainable development in communities has become an important issue that warrants consideration and research. Sustainable development thinking can help create more effective strategies, enhance the ability to organize information, and build a preferred future. During the COVID-19 pandemic, the nucleic acid testing booths in China played an important role in providing fast screening to determine community outbreaks and effectively prevent the spread of the virus. However, with the overall relaxation of the zero COVID-19 policy, many nucleic acid testing booths are currently largely idle. The question regarding how to leverage these testing booths scientifically and reasonably by redesigning them for local conditions is a ready-to-research topic. Based on theories such as future design and sustainable development construction of future urban communities, we focused on old urban communities in China and explored how to use idle testing booths by conducting field research and resident interviews. We thus aimed to explore how to redesign idle nucleic acid testing booths and transform them into products or smart mobile convenience service stations by applying the study’s qualitative results. Through a case analysis, we constructed design models for intelligent mobile convenience service stations in old communities that met the needs of the future urban community residents and promoted the sustainable development of the community. We hope that our results will be further verified via the design of intelligent convenience service stations in other cities.
Journal Article
Mitigating long queues and waiting times with service resetting
What determines the average length of a queue, which stretches in front of a service station? The answer to this question clearly depends on the average rate at which jobs arrive at the queue and on the average rate of service. Somewhat less obvious is the fact that stochastic fluctuations in service and arrival times are also important, and that these are a major source of backlogs and delays. Strategies that could mitigate fluctuations-induced delays are, thus in high demand as queue structures appear in various natural and man-made systems. Here, we demonstrate that a simple service resetting mechanism can reverse the deleterious effects of large fluctuations in service times, thus turning a marked drawback into a favorable advantage. This happens when stochastic fluctuations are intrinsic to the server, and we show that service resetting can then dramatically cut down average queue lengths and waiting times. Remarkably, this strategy is also useful in extreme situations where the variance, and possibly even mean, of the service time diverge—as resetting can then prevent queues from “blowing up.” We illustrate these results on the M/G/1 queue in which service times are general and arrivals are assumed to be Markovian. However, the main results and conclusions coming from our analysis are not specific to this particular model system. Thus, the results presented herein can be carried over to other queueing systems: in telecommunications, via computing, and all the way to molecular queues that emerge in enzymatic and metabolic cycles of living organisms.
Journal Article
Modeling and 6E analysis of a novel quadruple combined cycle with turbocompressor gas station
Natural gas compressor stations have a significant potential for waste heat recovery. In this paper, a novel quadruple combined cycle has been proposed based on a turbocompressor gas station. In this regard, Serajeh gas station in Qom (Iran), including three 25 MW nominal gas turbines that each turbine provided power requirement for compressor, has been considered. Steam and organic Rankine cycles have been used to recover waste heat and generate more power, which uses exhaust gas turbines. Seven organic fluids have been examined. Energy, Exergy, Exergoeconomic, Exergoenvironment, Emergoeconomic, and Emergoenvironmental (6E) analyses have better understood the system from different perspectives. In this regard, computer code has been developed in MATLAB for 6E analysis. Verification of thermodynamic simulation of developed code has been compared with THERMOFLEX software and reference data with high accuracy. Also, sensitivity analysis was carried out based on main parameters. Advanced exergy-based analysis associated with endogenous/exogenous and avoidable/unavoidable parts has been performed for deep analysis of each component. The results show an increase of approximately 16% in the integrated cycle's thermal efficiency compared to gas turbines. The combustion chamber has the highest exergy destruction rate, and the LP superheater and economizer have the lowest exergy efficiency. R113 was selected as the best organic fluid from thermodynamic and R141b from an economic and environmental point of view. Cost rates and environmental impacts of the entire system will be approximately 3300 $ h−1 and 2038 pts h−1, respectively.
Journal Article
On Transient Queue-Size Distribution in a Model of WSN Node with Threshold-Type Power-Saving Algorithm
This article proposes a queueing model of the operation of a wireless sensor network node, in which a threshold strategy for starting the node after a period of no transmission is used. In this model, transmission of packets is resumed when the number of packets in the accumulation buffer reaches a predefined level. In the literature, most of the results for models with limited access to the service station are obtained in equilibrium. In this paper, a formula for the Laplace transform of the transient queue-size distribution is obtained and written using the key input parameters of the system. The analytical apparatus uses the concept of the embedded Markov chain, the formula for total probability, renewal theory and some supporting algebraic results. Numerical examples are attached as well.
Journal Article
Relationships between state-level general population alcohol policies and birth outcomes: Results from 1972–2019 vital statistics
Research has found that policies that single out pregnant people's alcohol consumption are mostly ineffective. Identifying alternative approaches - for example, general population alcohol policies - that can reduce adverse effects of pregnant people's alcohol consumption is essential. Here, we examine how U.S. state-level alcohol policies regarding grocery store and gas station sales, Sunday sales, Blood Alcohol Concentration limits for driving, and government monopolies relate to birth outcomes.
Outcome data came from the 1972-2019 U.S. Vital Statistics System birth certificates (N = 160,538,939 live singleton births). Primary outcomes were low birthweight (<2,500 grams) and preterm birth (<37 weeks). Fully adjusted models included state and year fixed effects, state-specific time trends, and maternal- and state-level covariates with standard errors clustered by state.
The only significant, robust associations between policies and outcomes were for government monopolies. In fully adjusted models, having a government monopoly on spirits or on both spirits and wine retail sales (vs. none) were each related to lower odds of low birthweight births (aOR=0.94, 95% CI: 0.93, 0.95; aOR=0.95, 95% CI: 0.92, 0.98 respectively). Having a government monopoly on spirits sales was also significantly related to lower odds of preterm births (aOR=0.97, 95% CI: 0.95, 1.00).
Government monopolies on spirits and wine relate to better birth outcomes. Findings underscore the importance of maintaining state government monopolies on spirits and wine as a strategy for protecting against adverse effects of pregnant people's drinking.
Journal Article
Miniaturized 3D-Printed Cell Enables Water/Ethanol Quantification Using Electrochemical Impedance Spectroscopy
A miniaturized and low-cost electrochemical 3D-printed system for rapid and accurate quantification of ethanol content in ethanol fuel using electrochemical impedance spectroscopy (EIS) was developed. The monolithic design of the system incorporates insulating thermoplastic electrode separators, with only the cover being mobile, allowing for easy assembly and handling. The portable device, measuring approximately 26 × 24 mm, has a maximum capacity of 1 mL, making it suitable for lab-on-a-chip and portable analysis. By utilizing the dielectric constant of ethanol and ethanol fuel mixtures with water, the miniaturized EIS cell quantifies ethanol content effectively. To validate its performance, we compared measurements from four gas stations with a digital densimeter, and the values obtained from the proposed system matched perfectly. Our miniaturized and low-cost electrochemical 3D-printed device can be printed and assembled in two hours, offering a cost-effective solution for fast and precise ethanol quantification. Its versatility, affordability, and compatibility with lab-on-a-chip platforms make it easily applicable, including for fuel quality control and on-site analysis in remote locations.
Journal Article