Transportation Costs Research Articles

Vehicle logistics intermodal route optimization based on Tabu search algorithm

With the development of logistics enterprises and the adjustment of some relevant laws and regulations, the profit space of vehicle logistics enterprises has been further compressed. To reduce vehicle logistics transportation cost and increase the profit space of vehicle logistics, the vehicle logistics multimodal transport network is constructed and the graph traversal algorithm is used to screen the feasible paths in the vehicle logistics multimodal transport network. Then, the Tabu search algorithm can optimize vehicle logistics multimodal transport route model. Results showed that Tabu search performed better than other methods in solving route optimization problems. The cost of Tabu search algorithm after convergence was 1.2 yuan/km × per set. The performance of Tabu search algorithm on NGSIM data set was better than other methods. On this data set, the area under the curve of Tabu search algorithm was much higher than that of other methods. The optimization results of Tabu search for vehicle logistics intermodal routes were effective. Among the 15 routes, only four routes were not optimized, and other routes were optimized. After optimization, the profits have increased, and the profit of Route 9 had the largest increase, which was 18%. The research successfully constructs the optimization model of vehicle logistics intermodal route, and completes the solution to increase the profit space of vehicle logistics enterprises.

Forestry electric vehicle energy routing and mapping GIS tool

ABSTRACT In the United States, new laws and regulations in several states require increasing percentages of vehicles produced in the future to be zero emission to address climate-related issues. Manufacturers are producing more Electric Vehicles (EVs), but potential customers are hesitant to adopt EVs due to range anxiety. Log truck owners are particularly hesitant to invest in electric log trucks (ELTs) due to forest harvest operations remote nature. However, regenerative braking utilizing gravitational potential energy provides the opportunity to increase the range of ELTs. This manuscript presents the workflow for calculating and mapping energy transportation cost on an ELT using a GIS-enabled tool and demonstrates the tool’s applicability through a case study. The study area, the McDonald Dunn Research Forest, included 5,607 ha of forest stands partitioned into 357 harvest polygons averaging 15.7 ha, 326 harvest landings and 295 km of road. Using remotely sensed data from the study site, the tool digitalizes the wood supply chain and optimizes routing based on minimum energy expenditure, providing results such as trip energy cost, distance, and time. The results show the tools forest operations planning potential, applicability as a GIS navigation system, and provides EV buyers with a tool to make informed decisions when investing in technology that could combat climate-related issues. EV adoption will reduce reliance on fossil fuels and potentially ameliorate other environmental problems.

Enhancing Logistics Optimization

With the expansion of the logistics network, enterprise logistics distribution faces increasing challenges, including high transportation costs, low distribution efficiency, and unstable distribution networks. To address these issues, this study focuses on optimizing enterprise logistics distribution using a double-layer (DL) model. In this paper, we propose a DL model for optimizing enterprise logistics distribution. The DL model is designed to find the optimal solution using the particle swarm optimization (PSO) algorithm. By leveraging location data from the region, the DL model evaluates and compares alternative distribution centers to determine the most efficient distribution strategy. The results demonstrate that the DL site selection model developed in this study effectively addresses the tasks of logistics center location and distribution optimization among alternative distribution centers. Comparison tests reveal that the distribution path proposed by the DL model is more accessible and cost-effective compared to alternative approaches.

Decentralized Online Order Fulfillment in Omni-Channel Retailers

We consider an order fulfillment problem of an omni-channel retailer that ships online orders from its distribution center (DC) and brick-and-mortar stores. Stores use their local information, not observed by the retailer, that can lead them to accept or reject fulfillment requests of items in an online order. We investigate the problem of sequencing requests to stores and inventory rationing decisions at the DC to minimize expected costs under uncertain store acceptance behavior and when items are indistinguishable in terms of shipping. First, under the scenario that stores are used only when the DC has insufficient inventory, we propose a Markov Decision Process formulation and analyze the performance of myopic policies that are preferable because of their interpretability. We show that the performance rate of a myopic approach that orders stores by cost only depends on the number of items in an order, which is small in practice. We also determine conditions for the range of acceptance probabilities for the myopic policy to be optimal for small-sized orders. Using optimality conditions for a special case of the problem, we develop an adaptive variant of the myopic policy, and propose a new degree-based strategy that balances shipping costs and acceptance probabilities. Numerical testing suggests that the best-performing sequencing policy is within 1% of optimality on average. Moreover, using two years of data from a large omni-channel retailer in North America, we observe that adaptive policies, albeit more complex, are beneficial in reducing costs and split deliveries if acceptance rates can be estimated accurately. Second, we determine when the retailer should ship from stores or ration the inventory at the DC. We show that for single-item orders, the optimal policy has a threshold structure, where, remarkably, the highest priority region is also subject to rationing. We then consider the novel multi-unit-single-item rationing problem, and leverage the structure of the single-unit model to develop a heuristic. We numerically establish the efficacy of rationing models and our heuristic.

Logistics vehicle routing optimisation with synchronised transfer

This paper presents a synchronized transfer strategy in which operators can schedule logistics vehicles among employees and arrange the transfer of commodities. The transfer time consists of the vehicle waiting time and commodity transition time. By adopting the strategy, logistics vehicles can visit fewer communities, resulting in savings in transportation cost under ensuring punctual delivery. An integer programming model based on a space-time-state network is proposed to describe the complex transfer process. To simplify the model, time window and vehicle capacity constraints are embedded into the network. The alternating direction method of multipliers (ADMM) is designed to solve the model. In the ADMM-based solution framework, the original model can be converted into a series of shortest-path searching subproblems and iteratively solved using a dynamic programming (DP) algorithm. Our computational results show that the proposed model and algorithm are efficient and competitive.

Key fuel characteristics and techno-economic aspects of torrefied rubberwood biomass pellets produced by incorporating various cassava-based binders at varied doses.

Improving energy content and hydrophobic nature of woody biomass can be pursued through torrefaction. This gives torrefied biomass with a low bulk density, potentially increasing storage and transport costs. To overcome this issue, densifying the torrefied biomass is necessary. However, poor binding of particles makes densification challenging without using a binder. Therefore, the aim of this study was to investigate the physicochemical characteristics and techno-economic aspects of torrefied rubberwood biomass (TRWB) when pelletized using various cassava-based binders at different blending ratios. The selected binders included cassava starch (CS), cassava pulp (CP), and cassava chip (CC). Each binder at 5%, 10%, or 15% (wt.) was mixed with TRWB and water before pelletizing using a flat die machine. The results revealed that pelletizing TRWB with different cassava-based binders at various blending ratios influenced the physicochemical characteristics of the TRWB pellets, particularly dimensions, bulk density, fuel and atomic ratios, and energy content. The TRWB pellets demonstrated energy densities in the range of 7.95-11.39 GJ/m3, and their mechanical durability and fine content fell within acceptable ranges. The TRWB pellets maintained their shape during 120min of water soaking, with water absorption levels varying by binder dose. The pelletizing ability, material, and energy costs of TRWB pellets depend on binder type and dose. CP can be applied as a binder for pelletizing torrefied rubberwood biomass. However, the mechanical durability of the product needs to be above the user requirement or standard.

#1002 End of life healthcare utilisation and costs of older patients receiving kidney replacement therapy—analysis of Dutch health insurance claims data

Abstract Background and Aims The increasing prevalence of chronic kidney disease (CKD), an aging population and advancements in treatment options collectively contribute to a rise in older patients with a functioning kidney transplant (KTX) or undergoing dialysis. These treatments are associated with extensive healthcare utilisation, placing substantial demands on both patients and the healthcare system. Healthcare utilisation typically increases near the end of life, and is associated with increased costs. However, little is known about the end-of-life healthcare utilisation of patients receiving kidney replacement therapy (KRT). Therefore, our study aims to assess healthcare utilisation and costs during the last year of life. Method We analysed Dutch health insurance claims data from patients aged >65 years on KRT who deceased between June 2016 and December 2021. We matched each patient with two controls, defined as individuals who died within the same calendar year without any insurance claims related to CKD or KRT. Matching was performed on sex, age and socio-economic status. The primary outcomes were healthcare utilisation and costs in the last twelve months of life for patients treated with different KRT modalities and compared to matched controls. Healthcare utilisation was detailed at hospital and intensive care unit (ICU) admissions, emergency department (ED) and outpatient department (OPD) visits, hospital daycare and institutionalised care. Healthcare costs encompassed costs related to primary care, hospital care (inpatient and outpatient), mental care, institutionalised care, prescription medication, transportation and other costs. Hospital care costs were categorised as KRT-related and -unrelated costs. Results In total 7279 decedents were included; 4614 haemodialysis patients (HD), 766 peritoneal dialysis (PD) patients and 1899 KTx recipients. KRT patients had a mean age of 77.6 ± 6.6 years, with 64% being male, and had significantly more comorbidities than the control group. In the year preceding death, KRT patients had significantly more hospital admissions, ICU admissions, ED visits, outpatient visits, hospital daycare and institutionalised care than controls (see Fig. 1). When comparing across KRT-modalities, KTx patients were more often admitted to the ICU than HD and PD patients (p = 0.001 and p = 0.024, respectively). For both HD, PD and KTx patients, the mean number of days admitted to the hospital and ICU, as well as ED visits and OPD visits significantly increased in last three months preceding death, compared to the initial nine months of the last year of life (p < 0.0001). Mean total healthcare costs in the last year of life were €59.489 for KTx patients, €108.294 for PD and €117.520 for HD patients, compared to €19.820 for the controls. The majority of costs for dialysis patients were attributed to KRT, accounting for 55.5% (€65.216) and 60.0% (€64.559) of the total expenditures for HD and PD patients, respectively. In contrast, KRT-related costs constituted 25.7% (€15.262) of the total expenses in KTx patients. Besides substantial KRT-related costs, KRT-patients also incurred higher costs for specialist care in the hospital, primary care, medication and transport, compared to controls. Conclusion Healthcare utilisation is substantial for older KRT patients and intensifies during the last year of life. This is accompanied with elevated costs. Further research is necessary to evaluate the impact of healthcare utilisation on the quality of life and whether advanced care planning could prevent overutilisation.

Black soldier fly larvae feed suitability for chicken and prospects for economic valuation and viability aspects

Abstract Utilization of black soldier fly larvae (BSFL) emerges as a promising avenue for organic waste recycling and production of protein rich biomass. The current study explored the suitability of BSFL protein feed for chicken and economic facets associated with BSFL rearing facilities, encompassing costs of goods sold (COGs), operating expenditure (OpExp), and capital costs (CapExp). Research revealed that incorporation of BSFL feed for chicken did not exert discernible influences on overall meat quality. However, the amino acid content variation of chicken meat particularly concerning polyunsaturated fatty acids (PUFA), are correlated with the fatty acid composition of the BSFL feed, showed substrate-specific characteristics. The recommended BSFL dosage ranges up to 13% (defatted larvae), 12% (partially defatted BSFL), 14% (dried larvae), and 48% (for whole larvae), which did not affect the chicken body weight and physiological traits, except for the fatty acids profile. However, complete substitution at 100% proved detrimental to body weight. The establishment of a BSFL rearing facility is deemed economically viable, considering large production scales and supply chain development in collaboration with waste material managers. Such collaboration is envisioned to curtail substantial portions of expenses, primarily attributed to transport and labor costs, which constitute 60-70% of the financial outlay in the developing countries context. Based on the operational, capital, and marketing expenditures, the cost for BSFL rearing setup in Asian countries (Pakistan) ranged from US $50,762 to US $100,000, while the estimated profit was US $10,762 to US $51,121. These figures may vary based on cost per product, net price and profit per product, number of products sold, and market share and growth traction facets.

Simulation Method of Decarbonization of International Shipping for Evaluating the Impact of Possible Regulation Limiting GHG Intensity of Marine Fuels

This study explored how the GHG fuel standard (GFS) regulation affects international shipping quantitatively by simulating future fleet transformation, fuel consumption, and well-to-wake GHG emissions based on an inputted GHG fuel intensity pathway and scenario of transportation demand, fuel availability and costs, and technology availability. The method comprisesthree steps: calculating the amount of scrapped and built ships, allocating fuel type and mix, and calculating fuel consumption. We simulated how the regulation changes fleet composition and the mix of fuel consumption. From the perspective of feasibility and alternative fuels’ availability, some meaningful insights to implement the GFS regulation were delivered.

#Discreetshipping: Selling E-cigarettes on TikTok.

Youth and young adult use of e-cigarette products continues to remain high despite regulatory approaches to reduce youth access. This study sought to examine TikTok content regarding the sale and distribution of e-cigarettes. TikTok videos (n = 475) and metadata posted between June 2022 and August 2023 were scraped using a TikTok application programming interface and popular hashtags used to sell vaping products (ie, #discreetshipping [40.8 million], #puffbundle [14.8 million], #hiddennic [1.0 million]). After watching the 25 most viewed videos (39600-868800 views), a codebook was developed. All metadata were annotated using 11 unique codes: Small business, brand, cannabis, bundled, hidden, fake, international sales, no ID, order via Instagram, order via another method, and cost. Overall, 367 videos (with an average of 2017 likes) were deemed relevant. Videos advertised popular vaping brands (50.4%) that included cannabis products (45%). Products were described as bundled (28.6%), hidden (8.7%), and able to be shipped internationally (6%) without age verification (45.2%). Some videos (8.2%) evaded algorithms' detection of illegal activity by describing the post as "Fake." Customers were directed to other social media platforms (most often Instagram, 57.5%) and/or other websites/links (58.3%) to purchase products; 22.1% advertised discounts, free shipping, or low costs (ranging from $25-$35). Social media platforms, such as TikTok and Instagram, are being used to circumvent e-cigarette regulatory policies. Regulatory agencies should expand enforcement strategies to include social media platforms where users are illegally selling and distributing e-cigarettes internationally to young audiences. TikTok users across the globe are violating local, state, and federal laws by selling e-cigarettes concealed inside other products or bundled in packages that avoid detection. TikTok videos posted by self-proclaimed small business owners advertise discreet shipping practices that evade age verification in order to sell nicotine and cannabis bundles worldwide. Accounts used phrases describing the post to be "fake" to avoid detection by algorithms or TikTok administrators. E-cigarette regulatory agencies can partner with social media platforms to close regulatory gaps.

Minimization of metabolic cost of transport predicts changes in gait mechanics over a range of ankle-foot orthosis stiffnesses in individuals with bilateral plantar flexor weakness

Neuromuscular disorders often lead to ankle plantar flexor muscle weakness, which impairs ankle push-off power and forward propulsion during gait. To improve walking speed and reduce metabolic cost of transport (mCoT), patients with plantar flexor weakness are provided dorsal-leaf spring ankle-foot orthoses (AFOs). It is widely believed that mCoT during gait depends on the AFO stiffness and an optimal AFO stiffness that minimizes mCoT exists. The biomechanics behind why and how an optimal stiffness exists and benefits individuals with plantar flexor weakness are not well understood. We hypothesized that the AFO would reduce the required support moment and, hence, metabolic cost contributions of the ankle plantar flexor and knee extensor muscles during stance, and reduce hip flexor metabolic cost to initiate swing. To test these hypotheses, we generated neuromusculoskeletal simulations to represent gait of an individual with bilateral plantar flexor weakness wearing an AFO with varying stiffness. Predictions were based on the objective of minimizing mCoT, loading rates at impact and head accelerations at each stiffness level, and the motor patterns were determined via dynamic optimization. The predictive gait simulation results were compared to experimental data from subjects with bilateral plantar flexor weakness walking with varying AFO stiffness. Our simulations demonstrated that reductions in mCoT with increasing stiffness were attributed to reductions in quadriceps metabolic cost during midstance. Increases in mCoT above optimum stiffness were attributed to the increasing metabolic cost of both hip flexor and hamstrings muscles. The insights gained from our predictive gait simulations could inform clinicians on the prescription of personalized AFOs. With further model individualization, simulations based on mCoT minimization may sufficiently predict adaptations to an AFO in individuals with plantar flexor weakness.

Dual hesitant fuzzy set in multi-objective transportation problems in time sequence frame work

Decision makers may have different information in different situations when making decisions about the same attributes, depending on the circumstances. A time-sequential framework is necessary for navigating these kinds of circumstances. We established the notion of a Time-sequential dual hesitant fuzzy set (TS-DHFS) to illustrate the significance of time sequence in decision-making with the aid of a dual hesitant fuzzy set (DHFS), one of the important tools to handle the uncertainty embedded in the real world. The proposed set describes the hesitant situations more accurately by inducing a time sequence framework. We defined the fundamental operations, two score function for ranking and a series distance measures for the proposed set. For the pragmatic application of our proposed set, we devised the mathematical model in three different types of Time-sequential dual hesitant fuzzy multi-objective transportation problems (TS-DHF-MOTPs). The proposed three models are classified based on the nature of the parameters such as transportation cost (TC), transportation time (TT), availability, and demand. The goal of the proposed transportation systems is TC and TT simultaneously in a single framework. We established an approach utilizing one of the ranking functions that have been proposed, followed by the fuzzy programming (FP) and weighted sum technique (WST), to optimize the constructed models. Additionally, numerical computations are also carried out to emphasize the efficiency and benefits of MOTP under the TS-DHF environment.

A Study on the Effect Mechanism of Pectin Modification on the Carrot Cell Wall’s Texture Formation under Ultrasonic and Infrared Drying

The carrot has a high water content, and dehydration is an important means to extend its edible period and reduce storage and transportation costs. In the case of infrared (IR) drying, the porosity of the product is low and the structure is compact; the textural properties of the product are improved by using combined ultrasound and infrared (US-IR) drying; however, there is a lack of reports on the mechanism of this. Pectin has an important influence on the formation of the textural properties of fruit and vegetable tissues. In order to investigate the mechanism of the change in endogenous pectin properties in the carrot cell wall under US-IR drying on the improvement of the textural properties of the product, different fractions of pectins (water-soluble pectin, chelating pectin, alkali-soluble pectin) of the carrot were extracted, separated, and analysed. The thermal stability, component and content changes, Fourier infrared (FTIR), X-ray diffraction (XRD), esterification degree, molecular weight, monosaccharide composition, Ca ion content, and atomic force microscopy (AFM) of the pectins were determined. The results showed that the changes in the contents and properties of the carrot pectins under US-IR conditions had a positive effect on the improvement of the textural properties of the carrot tissues.

On-site hydrogen refuelling station techno-economic model for a fleet of fuel cell buses

Fuel cell electric buses (FCBs) have proven to be a technically viable solution for transportation, owing to various advantages, such as reliability, simplicity, better energy efficiency, and quietness of operation. However, large-scale adoption of FCBs is hindered by the lack of extensive and structured infrastructure and the high cost of clean hydrogen. Many studies agree that one of the significant contributors to the lack of competitiveness of green hydrogen is the cost of electricity for its production, followed by transportation costs. On the one hand, to reduce the investment cost of the electrolyzer, high operating hours should be achieved; on the other, as the number of operating hours decreases, the impact of the electricity costs declines. This paper presents an innovative algorithm for a scalable hydrogen refuelling station (HRS) capable of successfully matching and identifying the most cost-efficient levelized cost of hydrogen (LCOH) produced via electrolysis and connected to the grid, based on the HRS components' cost curves and the hourly average electricity price profile. The objective is to identify the least-cost range of LCOH by considering both the electric energy and the investment costs associated with a hydrogen demand given by different FCB sizes and electrolyzer rated powers. In addition, sensitivity analyses have been conducted to quantify the technology cost margins, and a cost comparison between the refuelling of an FCB fleet and the recharging infrastructure required for an equivalent fleet of Battery Electric Buse (BEB) has been performed. An LCOH of around 10.5 €/kg varying from 12 €/kg (2 FCB) to 10.2 €/kg (30 FCB) has been found for the best-optimized configurations. The final major conclusion of this paper is that FCB technology is currently not economically competitive. Still, a cost contraction of the electric energy price and the electrolyzer capital investment would lead to a 50% decrease in the LCOH. Furthermore, increasing renewable energies into the grid may shift the electricity cost curve, resulting in higher prices when the BEB recharging demand is more significant. This impact, in addition to the peak power load and longer recharging times, might contribute to bridging the gap with FCBs.

Determinants of Marketing of Handloom Products Across Heterogeneous Weaving Business Units: A Study of Rural Assam

Success in marketing plays an important role in the growth and extension of rural non-farm informal sectors. The present study made an attempt to understand the marketing success among diverse groups of handloom weaving business units and factors determining the marketing of handloom products through the lens of weaving business units in rural Assam. Besides descriptive and inferential statistics, multiple linear regression method was applied for the analysis of data. The results of the study show that the success of marketing in terms of sales volume and revenue was significantly higher among the master weavers. Factors like years of schooling of handloom weaving entrepreneurs, business experience, working hours, storage capacity, advance payment requirement, number of handloom competitors in village, transportation cost, communication expense, and proximity to market significantly influenced the marketing across heterogeneous weaving business units in the study area. Steps towards the improvement of rural market infrastructure and road connectivity by taking a slew of suitable policies by Central and state governments may allow the rural handloom weavers to get better access to the market, which in turn, may assist in the promotion of sales.

The content optimization of supplementary cementitious materials in coral sand-seawater cement mortar: A focus on mechanical properties and transportation costs

This study examines how supplementary cementitious materials (SCMs) such as fly ash (FA), blast furnace slag (BFS), and metakaolin (MK) affect the mechanical properties and transportation costs of coral sand-seawater cement mortar (CSSC). The Dinger-Funk equation was used to obtain the most densely packed design and preparation of coral sand and cementitious materials. The mechanical properties of CSSC were assessed utilizing the RMT testing apparatus. A thorough examination of the mechanical properties and transportation costs of CSSC was undertaken using the principle of value engineering and the effectiveness coefficient approach. Research results show that BFS10 has outstanding mechanical qualities in the binary cementitious system. Within the ternary cementitious system, the mechanical qualities typically exceed those of the binary system, with FA15BFS15 demonstrating the highest performance. The best appropriate mix ratio is FA15BFS15, as determined by a thorough examination and cost-benefit analysis. This ratio offers temporal sensitivity and maximized transit capacity. The SVR model is highly proficient in forecasting the compressive strength of CSSC, showcasing accurate prediction and data interpretation abilities. The research findings provide practical evidence for optimizing the proportion of CSSC in calcium sulfoaluminate cement, considering transportation expenses and algorithm prediction needs.

If it is adequate, it is not affordable: stakeholder perceptions on opportunities and constraints for pension reform in Indonesia

PurposeThe purpose of the study is to emphasise the urgent need for pension policy reform within Indonesia’s social security system.Design/methodology/approachThe methodology employed in this research includes qualitative techniques such as in-depth interviews and thematic content analysis.FindingsThe findings suggest various measures for pension reform, including revising eligibility criteria, adjusting benefit designs to cover housing and transportation costs, promoting Defined Benefit Plans, enforcing compliance, addressing insufficient contributions, advocating for transparency, and aligning social assistance programs with pension system enhancements. However, there is a trade-off between the adequacy of pension benefits and the amount of resources required.Research limitations/implicationsThis study is limited by the need for more individuals knowledgeable about pension issues in Indonesia, primarily due to their high-ranking positions, making access challenging and potentially compromising the small sample size in research.Practical implicationsThe research underscores the importance of maintaining policy consistency. It proposes a gradual increase in pension contributions as a pivotal strategy to ensure sustained financial security for retirees, particularly in the face of fiscal constraints. Also, the government should undertake comprehensive reforms, encompassing the revision of eligibility criteria, adjustment of minimum benefit designs, encouragement of employer contributions and effective management of compliance issues.Social implicationsSocial implications emphasise the importance of enhancing the financial security of retirees within Indonesia’s ageing population.Originality/valueThe originality and value of the research lie in guiding pension reform from the viewpoint of key policymakers involved in Indonesia’s pension system.

Sustainable gains from inland waterway investments at port-city interface

The objective of this research is to identify and quantify the sustainable impacts resulting from transportation investments at the port-city interface. These investments encompass two main components: 1) restoring the local inland waterway fairway for navigation, and 2) constructing a new railway bridge that traverses the primary waterway at the entrance of the seaport. The study is centered on the local transportation system in the northwestern region of Poland. Sustainability is assessed using an analytical tool derived from societal cost-benefit analysis and simulation in the relevant market transport performance in options with and without investment. Economic effects are evaluated in terms of savings in generalized transportation costs, which include transport operating expenses and travel durations. Environmental considerations encompass transport-related air pollution, greenhouse gas emissions, and well-to-tank emissions. Social aspects focus on issues like transport congestion, traffic noise, and transport-related accidents. Each type of investment yields distinct sustainable gains and distributes them among stakeholders differently. Additionally, the enhanced capacity of the rail bridge reveals the potential for a modal shift in the local passenger transport system, wherein passengers may transition from buses/cars to a fast railway. Tangible gains expressed in monetary terms allow for a sustainable assessment of transport investments. The elaborated research scheme can be employed to assess the sustainable ramifications arising from investments in intermodal transport at any port-city interface. It provides decision-makers with comprehensive insights into the economic, environmental, and social implications of various transport policies and interventions.

Hydrophobic micro-crosslinked sulfonated polystyrene flame retardant for simultaneous fire safety, transparency and high performance of polycarbonate

Sulfonate is considered to be the best flame retardant, which can endow polycarbonate (PC) excellent flame retardancy with low addition. Unfortunately, the water absorption and solubility of sulfonate will increase the cost of transportation and storage. In addition, sulfonate flame retardant is easy to migrate and precipitate from PC composites resulting in a negative impact on the sustainable use of PC materials. To ameliorate this issue, a sulfonate flame retardant (CSPS) with unparalleled hydrophobicity and thermal stability was synthesized through the incorporation of sodium p-styrene sulfonate as the main chain of crosslinked polystyrene. The PC/CSPS composites could pass UL 94 test V-0 rating with 0.3 wt.% CSPS addition, and the LOI is increased from 24.5 % to 31.4 %. Simultaneously, the PC/CSPS composites preserve their initial transparency. Moreover, the combustion test results indicated that the peak of heat release rate (PHRR) and the peak of smoke production rate (PSPR) of PC/CSPS-0.3 composites decreased by 40 % and 41 % respectively, and the time to reach PHRR and PSPR increased by 35.8 % and 56.5 % respectively. These results were attributed to the catalytic char formation and gas phase limitation of CSPS, which made PC composites with higher fire safety. Importantly, the PC/CSPS-0.3 composites can maintain tensile strength similar to that of PC. This research proposes a simplified and efficient methodology for fabricating PC composites with outstanding water resistance, flame retardancy, transparency, and mechanical fortitude, which is of considerable importance for the application of PC composites in emerging fields.

A competitive heuristic algorithm for vehicle routing problems with drones

We propose a heuristic algorithm capable of handling multiple variants of the vehicle routing problem with drones (VRPD). Assuming that the drone may be launched from a node and recovered at another, these variants are characterized by three axes, (1) minimizing the transportation cost or minimizing the makespan, (2) the drone is either allowed or not allowed to land while awaiting recovery, and (3) single or multiple trucks each equipped with a drone. In our algorithm, we represent a VRPD solution as a set of customer sequences and evaluate it via local search procedures solving for each sequence a problem that we refer to as the fixed route drone dispatch problem (FRDDP). Given a sequence of customers to be served by a single truck and its drone, the FRDDP selects a subset of customers to be served by the drone and determines drone launch and recovery nodes, while ensuring that each such customer is positioned between two nodes in the initial sequence. We introduce a heuristic dynamic program (HDP) to solve the FRDDP with reduced computational complexity compared to an exact solution algorithm for the problem. We reinforce our algorithm by developing filtering strategies based on the HDP. We benchmark the performance of our algorithm on nine benchmark sets pertaining to four VRPD variants resulting in 932 instances. Our algorithm computes 651 of 680 optimal solutions and identifies 189 new best-known solutions.