Supply Points Research Articles

Assessing spatial equity in urban park accessibility: an improve two-step catchment area method from the perspective of 15-mintue city concept

Ensuring equitable access to urban parks is crucial for promoting the sustainable development of cities. In the post-COVID era, the concept of the 15-minute city has gained significant attention, emphasizing human-scale urban design and fine-grained governance. This study introduces an improved two-step floating catchment area (2SFCA) method to accurately assess park accessibility and spatial equity in Guangzhou, considering the 15-minute city perspective. Firstly, a more effective framework is proposed to identify multiple park entrances that serve as supply points. Secondly, the population distribution is estimated using building areas and locationbased data through a random forest model. Furthermore, the supply capability index is estimated by considering the area of each park and its attractiveness index, derived from multiple geographic data sources. The results reveal unequal park accessibility in Guangzhou, with low-access areas mainly distributed on the fringe of study area in both walking and cycling scenarios due to the limited park supply or high-density population. With the influences of park entrances and the park attractiveness index, the spatial inequity of park accessibility may be more severe than previously estimated in other studies. This work enhances the understanding of park accessibility and facilitate effective planning for sustainable development and reducing environmental injustice.

Crossing non-parametric and parametric techniques for measuring the efficiency: Evidence from 65 European electricity Distribution System Operators

Benchmarking techniques have been one of the main tools used by National Regulatory Authorities (NRA) to provide reliable information to define the efficiency targets for regulated undertakings. This paper aims to define the operational efficiency of the Portuguese mainland electricity Distribution System Operator (DSO), a monopoly incumbent with more than six million customers. Given the monopolistic nature of the electricity distribution activity in Portugal, the analysis was supported on a wide sample of 65 European DSO that operate in 16 European countries. This geographic spread required the use of different data harmonization procedures for an adequate use of different methodologies, namely Stochastic Frontier Analysis (SFA), Data Envelopment Analysis (DEA) and Total Productivity Indices (Malmquist), in order to guarantee robust results for the efficiency assessment. The study combines two outputs (number of supply points and network extension) and two inputs (operating costs and total costs) in different models. The results obtained are relatively positive for Portuguese DSO, placing the mainland DSO at efficiency levels between the 1st quartile and the efficiency frontier. There is a high correlation between DEA and SFA predicted efficiency scores, which supports the robustness of the analysis.

Influence of vortical flow induced by a wall-mounted short cylinder with a streamlined front side on a horizontal air–solid two-phase flow

To induce large oscillations of air flow and suspend particles easily near the particle supply point in a low air velocity region of horizontal air-solid two-phase flow, a short cylinder model with a streamlined front side (refer to streamlined model) is proposed and is fixed on the bottom or top of the pipe in front of the particle feed. The streamlined front side of the model is designed to reduce the flow resistance, and the rectangular rear section of the model generates wake vortical flow so as to induce large airflow oscillation. The test tube consists of a horizontal pipe having an inner diameter of 80 mm and a length of 5 m. Spherical polyethylene particles with an average diameter of 2.3 mm and density of 978 kg/m3 were used as the test solid particles. Average air velocities and particle mass flow rates ranged from 9 to 16 m/s and 0.11 to 0.51 kg/s, respectively. Compared with the non-model air-solid two-phase flow, the streamlined model has reduced the pressure drop, critical and minimum conveying air velocities, power consumption, and additional pressure drop. This model achieved the highest reduction rate with a minimum air velocity of approximately 6% and an additional pressure loss of approximately 37.5%. According to particle image velocimetry measurement of air-solid two-phase flow, the time-averaged particle velocity and fluctuating particle velocity generated by the streamlined model are larger than those in the non-model flow, so even low air velocities can easily convey particles.

Energy Storage Capacity Optimization for Improving the Autonomy of Grid-Connected Microgrid

To support the autonomy and economy of grid-connected microgrid (MG), we propose an energy storage system (ESS) capacity optimization model considering the internal energy autonomy indicator and grid supply point (GSP) resilience management method to quantitatively characterize the energy balance and power stability characteristics. Based on these, we establish a three-stage coupled model including investment decision, day-ahead operation strategy, and real-time power fluctuation smoothing control. Investment processes solve the balance of ESS investment and internal energy autonomy. Day-ahead operational scheduling mainly solves unit commitment problems in MG, which are constrained by the ESS capacities. For real-time power fluctuation smoothing, we propose a power fluctuation smoothing control strategy, coordinated by ESS and direct load control (DLC), to achieve GSP resilience management. Furthermore, we use Monte Carlo Simulations, stochastic scenario combinations, and uncertainty set to characterize the fluctuations of both supply and demand at the above different stages, respectively. To solve the established model with multi-objective, multi-uncertainties, and multi-stage coupling, a robust counterpart method has been used to convert the uncertainty problem to the deterministic one, and then decomposition-based multi-objective evolutionary algorithm (MOEA/D) to efficiently used to solve the problem. Finally, simulations are conducted to verify the effectiveness of the proposed model.

Optimize location tower crane and supply facilities on construction site by discrete PSO algorithm

The optimal positioning of tower crane locations and material supply points on the construction site is an important task and is considered a complex combinatorial problem. Metaheuristics are popular and effective techniques for solving such problems. This paper introduces the application of the standard Particle Swarm Optimization (PSO) algorithm with discrete integer variables to solve the problem of optimizing the position of tower cranes and material supply points. A calculation program was built and numerical tests with 2 scenarios was conducted. The results show the performance of PSO and the applicability of the algorithm in the class of technical problems similar to the one under consideration.

Techno-economic analysis for off-grid green hydrogen production in Uruguay

The present study develops a techno-economic optimization model to determine and size the capacity of the renewable energy generation park, the electrolyzer, the storage system and the way to transport hydrogen which minimizes the levelized cost of hydrogen in Uruguay. To perform the optimization the model uses as input parameters the hydrogen demand, the distance to the point of supply, the renewable resource available and the year of construction of the project. In addition, this study analyzes the impact of the change of hydrogen demand scale (250, 15 &1.72tH2/d) and their technological maturity (2022 & 2030) on the cost of hydrogen production and each stage of the chain. The cost of energy, the demand for hydrogen, and any penalties for not supplied hydrogen determine the required storage capacity. It was found that for large hydrogen demands, the cost of renewable energy represents the single most relevant cost of the green hydrogen value chain. For medium and small hydrogen demands the combined cost of conversion, processing, transport and storage possess a similar weight to the energy costs on the total hydrogen cost. On the other hand, for the selected locations, the transport of compressed gas by pipelines is the most competitive for the larger demands, and compressed gas transportation by trucks for the small demands, as expected. For a medium demand of 15tH2/d it was found that larger distances favor the liquid organic hydrogen carrier transportation by trucks while shorter distances favor compressed gas transportation by trucks. Finally, a greater maturity of electrolyzers, hydrogen storage systems and renewable generation are expected to significantly reduce the cost of hydrogen production in the medium term, which will allow decreasing the total cost of hydrogen from 3.5USD/kgH2 in 2022 to 2.3USD/kgH2 in 2030.

Assessing Challenges of Potable Water Supply, Demand and Enhancing Sustainability

This paper presents the challenges of water supply demand and enhancing water sustainability in rural areas. Data collected from field observation, regional water offices and officials, questionnaires and community responses were conducted. Data from the selected districts of the study area was discussed and analyzed. Two hundred seventeen water supply points (one hundred thirty hand-dug wells, thirty-five rope pumps, forty-eight spring development, and five shallow wells) are constructed in the study area. Among these water points, one hundred ninety-four were functional during the study time, and twenty-three were non-functional. Developed spring and rope pumps account for 22.11% and 16.12% of the total, respectively. In contrast, the hand-dug well and shallow wells as a source of water account for 59.9 % and 2.3%, respectively. The communities in the study area also use rivers and unprotected springs as water sources. This study found that the water supply in the study area is far less adequate for multiple reasons. The rural water supply system fails due to inappropriate design and underestimating population growth while designing water supply by considering only the existing population. The social and economic importance of providing a potable water supply is widely recognized. The study elicited why water supply systems have become inadequate in the area. This study may be helpful to have sufficient information before launching significant investments in rural water supply works.

Segmentation of a conventional medium voltage network into solar PV powered microgrid

This paper aims to convert a feeder of a bulk supply point (BSP) into a microgrid with rooftop solar PV plants sited in senior high schools along that MV grid in Ghana. The study used a solar PV Python optimization and forward–backwards algorithms to arrive at its results. The results show that rooftop PV plants sited in the study area can produce electricity to meet the feeder’s peak demand (8.2 MW) and have an extra 11.3 MW fed back to the grid. Cases 1, 2, 3 and 4 saw increases of 1.16%, 1.74%, 2.26% and 2.32%, respectively, higher than the nominal voltage of 34.5 kV. The base case total loss was 1.1 MW, and case 1 was 0.3 MW.

A detailed analysis of electricity consumption at the University of Castilla-La Mancha (Spain)

The current energy crisis has drastically altered forecast electricity plans and budgets for European university campuses. This situation heightens the need to analyze their electrical consumption, with two main goals: identifying their patterns and promoting the development of renewable installations for these consumers. Previous research has focused only on aggregated demand data, with the studies being based on estimations and forecasts, and focused mainly on single buildings. Moreover, there is a lack of scientific papers that provide a replicable codebase for electricity analysis. Our work presents a novel methodology to overcome these research gaps, proposing the first comprehensive, replicable and scalable codebase to analyze electricity consumption in universities. It is based on three steps. The first comprises automated data collection of real electricity measurements at each electricity supply point. The second develops the complete analysis of electricity consumption. The last step parameterizes this consumption by identifying seasonal and daily profiles. The research was applied to the University of Castilla-La Mancha, campus Albacete (Spain) case study. The results revealed the 4 highest electricity-demanding buildings: Biomedical Complex, Higher Technical School of Industrial and Computer Engineering, Vice-rectorate and Library, and Higher Technical School of Agricultural and Forestry Engineering. The results are thus of great value for other educational buildings.

Determination of Aflatoxin B1 Contents in Peanut Protein Snack Bars

Peanuts, which are rich in nutrients, are used in many products and are often a primary ingredient of protein bars. However, when the necessary production and storage conditions are not met, mycotoxins, and particularly aflatoxin B1 (AFB1), which is the most toxic and most common mycotoxin, may pose a great risk. This study was undertaken to indirectly examine the appropriateness of storage conditions for peanut protein bars sold at different supply points and to identify the presence of AFB1 in compliance with the relevant legal limitations. In February and March 2022, different varieties of peanut protein bars without added sugars were obtained from local markets and nonmarket store chains (places where sports products, cosmetic products, and protein bars are sold) in Ankara, Turkey. AFB1 contents were analysed by the enzyme-linked immunosorbent assay (ELISA) method. The limit imposed by the Turkish Food Codex regulation on contaminants is 5 ppb. While 38.3% of the samples were under that limit, 61.7% were above. No significant difference was found for the place of sale ( p = 0.542 and χ2 = 2.150), selling conditions ( p = 0.497 ), product ingredients, or remaining shelf-life ( p = 0.804 ) regarding the level of AFB1 in the samples. However, it was determined that samples with peanut percentages lower than 17.0% had higher amounts of AFB1 ( p < 0.001 ), and other available ingredients might affect the AFB1 content of peanut bars. It was concluded that most samples (n = 37.0, p < 0.001 , t = −8.607) posed a risk in terms of AFB1. Considering the shelf-life of such products and that peanuts can produce AFB1 during their shelf-life, it would be beneficial to monitor the frequency of supervision and prevent the sale of peanut bars with AFB1 contents higher than the limits.

Analysis of single-phase grounding fault and its protection in the medium and low voltage distribution system

The single-phase ground fault of the medium and low voltage distribution system occurs most frequently in the distribution network. The fault should be eliminated in a short time. The single-phase ground short circuit fault that occurs when the neutral point of the power supply is not directly grounded in the medium and low voltage distribution network should be simulated and analyzed. The study seeks to understand the trend of voltage and current as well as the changes of its amplitude and phase when the fault occurs, which are consistent with the theoretical calculation and analysis. According to the analysis of single-phase grounding fault based on the simulated data, the acquisition of zero sequence current, the protection configuration, and the method of setting the point are discussed.

Simulation for Appropriate Mean Selection for Can's Approximation Method in Transportation Models

Classical transportation models aim to minimize the total costs of homogeneous goods transport from supply points to demand points, taking into account unit transportation costs. They constitute a special case of network models and employ a technique based on linear programming. Suggested in 2015 and one of the early distribution methods, Tuncay Can’s Approximation Method (TCAM) is based on the geometric averages of unit transportation costs, although it is stated in the theorem that other means than geometric can be used. The aim of this study is to compare the total costs of a transportation model by solving a problem using geometric, arithmetic, square, and harmonic means based on TCAM. The coefficients of the transportation model were obtained randomly by simulation, and the method was repeated on the problem according to the different means and the appropriate means determined.

Analisis Sistem Distribusi BBM Dengan Menggunakan Konsep Cost-Based Value Stream Mapping di PT. Pertamina

PT. Pertamina (Persero) Marketing Operation Region 1 (MOR1) oil fuel Terminal (TBBM) Medan Group has a problem that is less optimized the cost of the company's operational activities so as to reduce the company's profit then in this research combine the concept of cost-based and value stream mapping by describing the flow of information and material on the value stream and continued by calculating the cost based. After the calculation of the results can be obtained before the cost reduction, then the company to run its operational activities that consist of the process of acceptanming its duties and responsibilities as a distribution of fuel so that the operational activities of the company issued a distribution fee of Rp. 3.964,- / liter, then from the supply point switching there are 68 industrial companies that can be transferred to the fuel Terminal Pematangsiantar and 34 diverted to the fuel Terminal range so that the company can reduce the cost of distribution fuel by Rp. 2.429,-/liter.ce, filling and distribution of fuel to issue a distribution fee of Rp. 6.393,-/liter, by describing the value stream of identification of some waste namely waste waiting, waste over processing, waste motions and waste of transportation. After the improvement is the reduction of waste and supply point transfer to several industrial companies, the company can create effectively and efficiently in perfor.

The use of remote sensing data sources and GIS in fire protection planning in biebrza national Park, with special attention to non-forest ecosystems

ABSTRACT In the spring of 2020, a large-scale fire destroyed 5,526 hectares of wetlands in Biebrza National Park. It was decided to modernize the park’s fire protection system. It proved necessary to develop rules for fire protection in large natural areas where non-forest communities predominate. A team of experts from the Forest Research Institute, the Fire Department, and the Biebrza National Park developed methods for fire protection in the park based on open, publicly available remote sensing data sources. The following methods were developed or modified and adapted to the conditions of the park: determination of fire danger, prediction of fire danger, modeling of fire development, determination of the network of fire access roads, determination of water supply points, including water withdrawal points for helicopters, detection of fires, functioning of the alarm and communication system, firebreaks, places of concentration of forces and resources, equipment for fire fighting, and taking preventive measures. The developed principles of fire protection in the Biebrza National Park, based on open remote sensing data and the technology of GIS, will enable the creation and operation of a system that will reduce the probability of fires in the future.

Allocation of emergency medical resources for epidemic diseases considering the heterogeneity of epidemic areas.

The resources available to fight an epidemic are typically limited, and the time and effort required to control it grow as the start date of the containment effort are delayed. When the population is afflicted in various regions, scheduling a fair and acceptable distribution of limited available resources stored in multiple emergency resource centers to each epidemic area has become a serious problem that requires immediate resolution. This study presents an emergency medical logistics model for rapid response to public health emergencies. The proposed methodology consists of two recursive mechanisms: (1) time-varying forecasting of medical resources and (2) emergency medical resource allocation. Considering the epidemic's features and the heterogeneity of existing medical treatment capabilities in different epidemic areas, we provide the modified susceptible-exposed-infected-recovered (SEIR) model to predict the early stage emergency medical resource demand for epidemics. Then we define emergency indicators for each epidemic area based on this. By maximizing the weighted demand satisfaction rate and minimizing the total vehicle travel distance, we develop a bi-objective optimization model to determine the optimal medical resource allocation plan. Decision-makers should assign appropriate values to parameters at various stages of the emergency process based on the actual situation, to ensure that the results obtained are feasible and effective. It is necessary to set up an appropriate number of supply points in the epidemic emergency medical logistics supply to effectively reduce rescue costs and improve the level of emergency services. Overall, this work provides managerial insights to improve decisions made on medical distribution as per demand forecasting for quick response to public health emergencies.

Systematic risk management for aplanned gas shutdown in the high-care facility of auniversity hospital

In the course of building extension works at Dresden University Hospital, it was necessary to shut down the central medical gas supply in abuilding with 3 intensive care wards with 22beds, an operating theater tract with 5 operating rooms and 6 normal wards each with 28beds during ongoing services. Thus, for the construction phase there was aneed to establish an interim decentralized gas supply with zero failure tolerance for the affected functional units . Following established procedures for possible risk and failure analysis, aproject group was set up by the hospital's emergency and disaster management officer to develop aproject plan, aneeds assessment and acommunication plan. Avariety of risk factors were systematically identified for which appropriate countermeasures needed to be designed. The needs assessment over 4 h based on physiological parameters for the maximum available 22ventilator beds resulted in 26,000 l of oxygen and 26,000 l of compressed air. A total of 7 supply points were each equipped with two 50l cylinders for both oxygen and compressed air, with atotal availability of 175,000 l of each of the 2 gases. Another eight cylinders each were held in reserve. The project was carried out on aSaturday without an elective surgery program, so that the operating rooms concerned could be closed. The timing was chosen so that double staffing of intensive care personnel was available during the afternoon shift change. In advance, as many of the patients on mechanical ventilation as possible were transferred within the hospital; however, nine of the mechanically ventilated patients had to remain. The technical intervention in the gas supply lasted only 2 h without affecting the patient's condition. During the 2‑h interim supply, 16,500 l of compressed air and 8000 l of oxygen were consumed on the high-care wards. The calculated hourly consumption per ventilated patient was 917 l of air (15 l/min) and 444 l of oxygen (7 l/min). The quantity framework based on empirical values from intensive care medicine was significantly lower. This was more than compensated for by the 10-fold stocking of gas and the predictably lower number of ventilated patients than the maximum occupancy used as abasis. For technical interventions in high-risk areas, careful planning and execution in an effective team is required. Established procedures of project management and risk assessment help to avoid errors.

Spatial Accessibility and Equity Evaluation of Medical Facilities Based on Improved 2SFCA: A Case Study in Xi'an, China.

Accurate evaluation of the accessibility of medical facilities is a prerequisite for the reasonable allocation of medical resources in a city. The accessibility of medical facilities depends not only on the distance to the supply and demand points, but also on the time spent in the process, and the supply capacity of the supply points. Taking Xi'an City of Shaanxi Province as an example, this paper comprehensively considers the facility supply capacity and introduces the selection probability function based on the two-step floating catchment area (2SFCA) method. In addition, in order to approximate the residents' acceptance of different types of hospitals for long-distance medical treatment in real situations, different levels of search radius were set for the different levels of hospitals, and ArcGIS was used to measure the accessibility and evaluate the spatial layout of medical facilities in the main urban area of Xi'an. The results show that there is a significant difference in the accessibility of medical facilities in the main urban area of Xi'an, and the accessibility tends to decrease gradually from the central city to the periphery. The inequity in the allocation of medical facilities in the main urban area of Xi'an is more obvious, with about 81.64% of people having access to 54.88% of medical resources. The accessibility evaluation model established by the improved 2SFCA method can obtain more accurate and objective evaluation results. This study can provide a reference basis for urban medical facilities' planning and rational spatial layout.

Microbial Profiles of Meat at Different Stages of the Distribution Chain from the Abattoir to Retail Outlets.

Meat has been found to be a prime vehicle for the dissemination of foodborne pathogens to humans worldwide. Microbial meat contaminants can cause food-borne diseases in humans. The threat to consumers by microbial meat contaminants necessitates the studying of meat microbial loads to prevent potential illnesses in consumers. Studies investigating the meat microbial loads in South Africa are limited. The objective of this study was to compare microbial contamination of different meat types from low-throughput (LTA) and high-throughput abattoirs (HTA) at three stages of the distribution chain from abattoir to retail outlets. Beef, pork, and mutton (n = 216) carcasses were sampled: during the loading process at the abattoirs, when off-loading at the supply points and during marketing. All samples were subjected to total bacterial count (TBC), coliform count (CC), presumptive Escherichia coli (E. coli) (PEC) and Staphylococcus aureus (S. aureus) detection. In mutton, TBC dominated at loading, CC was similar across distribution chain stages, PEC was the predominant microbial contaminant at the offloading stage at the HTA, but TBC was affected at loading, CC was similar across distribution chain stages, PEC was affected at loading, and S. aureus was affected at the display stage at the LTAs. In beef, TBC had similar levels at loading; CC and PEC dominated at the display stage for the HTAs. However, TBC was affected at the display stage; CC was similar across stages; PEC was affected at the offloading stage at the LTAs. In pork, higher contamination levels were discovered at the display stage, CC dominated at the loading stage, with PEC detected at offloading at the HTAs but TBC, CC, PEC and S. aureus were similar across stages at the LTAs. TBC, CC and PEC were affected by the storage period and meat supplier to meat shop distance whereas distance affected the TBC, CC and PEC. Meat supplier to meat shop distance negatively correlated with meat distribution chain stage but positively correlated with TBC, CC and PEC such as temperature. Temperature positively correlated with meat distribution chain stage and shop class. Meat distribution chain stage was negatively correlated with storage period, TBC, CC and PEC but positively correlated with shop class. Shop class negatively correlated with storage period, TBC, CC and PEC. Storage period positively correlated with TB, CC and PEC. TBC and meat type positively correlated with CC and PEC. CC positively correlated with PEC but negatively correlated with S. aureus such as PEC. In conclusion, mutton, pork and beef meat are susceptible to microbial contamination at distribution chain stages in abattoirs.

Impact of transport and storage practices on the microbiological quality of drinking water in Godomey district (Abomey‐Calavi municipality) in the Republic of Benin

AbstractThe aim of this study was to assess the risk of drinking water contamination during transportation and storage at the household level of Godomey district in Benin. A survey carried out in 175 households was followed by a microbial analysis of water samples at the point of supply and after transport and storage in households over a period of 4 days. The results of the surveys showed that households obtain their supplies in water mostly from the network of the National Water Company of Benin (SONEB). In addition, they used private boreholes and wells as source of the drinking water. People who did not have direct access to water sources traveled a few meters with different materials (cans, plastics, basins) to obtain water and store it in households for their daily needs. This water was used for several days (1–7) before the renewal of the storage. The microbiological results revealed an increase in microbial contamination, specifically total germs and total coliforms, after transport and storage when compared with the point of supply, and as time passed. The fecal contamination was expressed by the presence of Escherichia coli. According to the study, 17% of well samples are polluted on the first and second days and are classified as dangerous quality. After 4 days, this pollution had spread to 50% of well samples. In addition, 17% of borehole water samples were found to be of poor quality, and none of the SONEB samples were contaminated with E. coli.

Integrated mathematical optimisation approach for the tower crane hook routing problem to satisfy material demand requests on-site

Optimising decisions around the location and operation of tower cranes can improve the workflow in construction projects. Traditionally, the location and allocation problems involved in tower crane operations in the literature have been solved separately from the assignment of material supply points to demand points and the scheduling of the crane’s activity sequence across supply and demand points on a construction site. To address the gap, this paper proposes a binary integer programming problem, where location of the tower crane, allocation of supply points to material-demanding regions, and routing of hook of the crane based on activity sequencing of the hook across supply and material-demanding regions on site are optimised. The novelty in this work is in the way the crane’s activity scheduling is modelled via mathematical programming, based on routing the hook movement to meet material demand, through minimising tower crane operating costs. A realistic case study is solved to assess the validity of the model. The model is contrasted with results obtained from other solving algorithms commonly adopted in the literature, along with a solution proposed by an experienced practitioner. Results indicate that all instances can be solved when compared to other meta-heuristics that fail to achieve an optimum solution. Compared to the solution proposed by the practitioner, the results of the proposed model achieve a 46% improvement in objective function value. Planners should optimise decisions related to the location of the crane, the crane’s hook movement to meet service requests, and supply points’ locations and assignment to material-demanding regions simultaneously for effective crane operations.