Key Constraints Research Articles

How great is the Great Glen Fault?

A popular conceptual tectonic model envisages the Great Glen Fault to be part of a sinistral strike-slip system active during the mid-Silurian through early Devonian with c. 700 km of displacement. Here we use sedimentological, geochemical and detrital zircon age data to show that restoring 250–300 km of displacement suffices to fulfil key geological constraints and reveal three new pre-strike-slip relationships: (i) Paleoproterozoic Makkovik-Ketilidian crust becomes placed proximal to numerous immature sandstone units in the Grampian and Northern Highlands of Scotland and County Mayo, Ireland, that are marked by single-mode peaks of 1.8–1.6 Ga detrital zircons sourced from that crust; (ii) the two most concentrated occurrences of appinite and metadolerite/gabbro in the Scottish-Irish Caledonides become matched; and (iii) the Donegal and Argyll granite suites can be paired. That amount of displacement provides, at least in part, the separation required between the Northern and Grampian Highlands to account for Scandian-age (Silurian) deformation in the former and its absence in the latter.

A novel double stator hybrid-excited Halbach permanent magnet flux-switching machine for EV/HEV traction applications

This research paper introduces the Double Stator (DS) Hybrid Excitation (HE) Halbach Permanent Magnet (HPM) Flux Switching (FS) machine. The machine construction and its optimization specifically designed for electric vehicle (EV)/hybrid electric vehicle (HEV) traction applications are investigated. The optimization using a multi-objective Genetic Algorithm is conducted following a sensitivity analysis-based identification of key optimization parameters and constraints. The finite element results are compared with the performance of a state-of-the-art benchmark FSPM machine having identical PM volume and winding current densities. The proposed design is shown to outperform the benchmark with 16.2% increase in back-electromotive force and 14.7% reduction in cogging torque. Furthermore, the average torque is improved at flux-enhancing operation by 20.8%, and the torque ripple is reduced by 9.9%. Notably, the proposed machine also is capable of flux regulation thereby having the ability to operate in a wide speed range. A detailed explanation of the reasons for the significant improvements in the proposed machine structure is provided to offer a comprehensive understanding of its rationale. These research findings indicate that this innovative DS-HE-HPM-FS machine can enhance the performance of EVs and HEVs.

Thermal and electromechanical performance in BaSnO3-modified potassium sodium niobate piezoceramics via two-step sintering

In view of industrial applications requiring high piezoelectric activity, KNN-based ceramics face two key constraints: insufficient density and temperature sensitivity. To address these challenges, this study first introduces BaSnO3 and employs two-step sintering method (TSS) for fabrication, thereby synthesizing ternary 0.975K0.5Na0.5NbO3-0.025Bi0.5K0.5TiO3-xBaSnO3 (KNN-1000xBaSn; x = 0, 0.3 %, 0.6 % and 0.9 %) with superior piezoelectricity (d33 = 217–257 pC/N; d33* = 265–330 pm/V; S = 0.16–0.21 %), high Curie temperature (TC = 325–349 °C) and densification (4.3–4.5 g/cm3; relatively density ∼96 %). In one respect, the TSS allows minimal volatilization of alkali metals while promoting grain homogenization. In another respect, the introduction of BaSnO3 enhances the mobility of domain walls, meanwhile fosters diffuse phase transitions (DPT) and widens dielectric peaks without significantly impairing TC. Moreover, the KNN–6BaSn obtain not only reinforced d33 (256 pC/N) with high TC (325 °C) and ε′ (1016), but also fatigue resistance and extreme-temperature endurance with excellent d33* (445 pm/V at 90 °C; 300 pm/V at 180 °C). This work provides a resultful dual-strategy for the emergence of lead-free piezoelectric products.

PEMASARAN DAN BUDI DAYA BUNGA ANGGREK DI PAMULANG TANGERANG SELATAN

The orchid cultivation and marketing industry in South Tangerang has shown significant development within the horticultural sector. This study explores the general conditions of orchid cultivation, including environmental factors conducive to plant growth and common cultivation techniques. Additionally, the study delves into aspects of orchid marketing, covering strategies employed in marketing local orchid products and addressing challenges in both local and export markets. In the context of technology, the research highlights the role of modern technology in orchid cultivation development, from growth monitoring to harvest processing systems. Key constraints in the industry are also discussed, alongside case studies of successful farmers or companies navigating challenges and leveraging opportunities in the orchid cultivation and marketing industry. The findings aim to provide valuable insights for further development in the orchid industry in South Tangerang, serving as a foundation for sustainable policies and best practices to advance the sector

Power-Efficient Resource Allocation for Active STAR-RIS-Aided SWIPT Communication Systems

Simultaneous wireless information and power transfer (SWIPT) has emerged as a pivotal technology in 6G, offering an efficient means of delivering energy to a large quantity of low-power devices while transmitting data concurrently. To address the challenges of obstructions, high path loss, and significant energy consumption associated with long-distance communication, this work introduces a novel alternating iterative optimization strategy. The proposed approach combines active simultaneous transmission and reflection of reconfigurable intelligent surfaces (STAR-RIS) with SWIPT to maximize spectrum efficiency and reduce overall system energy consumption. This method addresses the considerable energy demands inherent in SWIPT systems by focusing on reducing the power output from the base station (BS) while meeting key constraints: the communication rate for information receivers (IRs) and minimum energy levels for energy receivers (ERs). Given complex interactions between variables, the solution involves an alternating iterative optimization process. In the first stage of this approach, the passive beamforming variables are kept constant, enabling the use of semi-definite relaxation (SDR) and successive convex approximation (SCA) algorithms to optimize active beamforming variables. In the next stage, with active beamforming variables fixed, penalty-based algorithms are applied to fine-tune the passive beamforming variables. This iterative process continues, alternating between active and passive beamforming optimization, until the system converges on a stable solution. The simulation results indicated that the proposed system configuration, which leverages active STAR-RIS, achieves lower energy consumption and demonstrates improved performance compared to configurations utilizing passive RIS, active RIS, and passive STAR-RIS. This evidence suggests that the proposed approach can significantly contribute to advancing energy efficiency in 6G systems.

Chirality-Induced Magnet-Free Spin Generation in a Semiconductor.

Electrical generation and transduction of polarized electron spins in semiconductors (SCs) are of central interest in spintronics and quantum information science. While spin generation in SCs is frequently realized via electrical injection from a ferromagnet (FM), there are significant advantages in nonmagnetic pathways of creating spin polarization. One such pathway exploits the interplay of electron spin with chirality in electronic structures or real space. Here, utilizing chirality-induced spin selectivity (CISS), the efficient creation of spin accumulation in n-doped GaAs via electric current injection from a normal metal (Au) electrode through a self-assembled monolayer (SAM) of chiral molecules (α-helix l-polyalanine, AHPA-L), is demonstrated. The resulting spin polarization is detected as a Hanle effect in the n-GaAs, which is found to obey a distinct universal scaling with temperature and bias current consistent with chirality-induced spin accumulation. The experiment constitutes a definitive observation of CISS in a fully nonmagnetic device structure and demonstration of its ability to generate spin accumulation in a conventional SC. The results thus place key constraints on the physical mechanism of CISS and present a new scheme for magnet-free SC spintronics.

Uncovering the Triple Synergy of New-Type Urbanization, Greening and Digitalization in China

The in-depth discussion and analysis of the synergistic effect of new-type urbanization, greening and digitalization (NUGD) is important for the achievement of sustainable social, ecological and economic development. Therefore, in this study, an evaluation index system composed of these three subsystems was constructed for Chinese cities from 2011 to 2021. The comprehensive and collaborative development levels of each subsystem were measured by means including the entropy weight method and the coupling coordination model, respectively. Then, methods such as ESDA and the Dagum Gini coefficient were applied to investigate the spatiotemporal evolution and spatial differences in the triple synergy effect of the NUGD system in Chinese cities. Finally, the constraining factors of the triple synergy effect were revealed using the obstacle degree model. The findings demonstrated the following: (1) Overall, the NUGD subsystems and their comprehensive levels were increasing, with moderate overall development levels. (2) The synergistic development of the NUGD system exhibited an upward trend. Spatially, the synergistic development level showed distinct differentiation, being higher in the east and lower in the west. The multidimensional dynamic variation characteristics obtained through kernel density estimation revealed that the triple synergy level exhibits high stability. (3) The differences within the east and between the eastern and western areas were the largest, with the intensity of transvariation as the main source. (4) The five criterion layers, including social and spatial urbanization variables, were the key constraints that affected the triple synergy of the NUGD in Chinese cities, and the restrictive role of factors such as the proportion of urban construction land and the per capita postal business volume should not be ignored. This study provides a valuable reference and decision-making guidance to promote China’s acceleration toward a new urbanization path supported by both digitalization and green transformation.

3D lithiophilic collector coated by amorphous g-C3N4 enabling Ultra-Stable cycling Li metal batteries

Lithium metal batteries (LMB) are thought of the most promising candidates for the next generation of high energy density batteries, but the problems of interface instability and uncontrollable dendrite growth are key constraints to the commercial application. Herein, we constructed an amorphous graphitic carbon nitride (g-C3N4) “outerwear” modified lithiophilic 3D Au/CoO nanoarray matrix (CACM) as a multifunctional dual-layer host, achieving dendrite-free and cycling stabilized Li metal anode. The density functional theory (DFT) calculations show that the reaction between CACM and Li atoms has a strong binding energy and a large amount of charge transfer. The lithiophilic 3D host induces Li metal uniform deposition with a low nucleation barrier within the 3D skeleton. The amorphous g-C3N4 “outerwear” can effectively avoid direct contact between the electrolyte and Li and reduce the irreversible side reaction. Meanwhile, the g-C3N4 layer has abundant Li ion transport channels, which facilitated fast Li+ transfer and modulate the ion concentration over the anode surface. Thus, the half-cell equipped with the CACM electrode has ultra-high cyclic stability, maintaining a CE value of 99.6 % over 230 cycles at 1 mA cm−2 with 1 mAh cm−2. The symmetric-cell can maintain a low overpotential stable run 1300 cycles at 10 mA cm−2. Similarly, the full cell also showed outstanding long-term cycle stability (capacity maintained at 96.3 % after 400 cycles at 1C) and superior rate capability. The in-situ visualization cell test and ex-situ SEM also demonstrated that the multifunctional host inhibits volume expansion and the dendritic growth of Li.

Interaction structure constrains the emergence of conventions in group communication

Real-world communication frequently requires language producers to address more than one comprehender at once, yet most psycholinguistic research focuses on one-on-one communication. As the audience size grows, interlocutors face new challenges that do not arise in dyads. They must consider multiple perspectives and weigh multiple sources of feedback to build shared understanding. Here, we ask which properties of the group's interaction structure facilitate successful communication. We used a repeated reference game paradigm in which directors instructed between one and five matchers to choose specific targets out of a set of abstract figures. Across 313 games (N = 1,319 participants), we manipulated several key constraints on the group's interaction, including the amount of feedback that matchers could give to directors and the availability of peer interaction between matchers. Across groups of different sizes and interaction constraints, describers produced increasingly efficient utterances and matchers made increasingly accurate selections. Critically, however, we found that smaller groups and groups with less-constrained interaction structures ("thick channels") showed stronger convergence to group-specific conventions than large groups with constrained interaction structures ("thin channels"), which struggled with convention formation. Overall, these results shed light on the core structural factors that enable communication to thrive in larger groups.

Green Wave Control Model Simultaneously Considering Passenger Cars and Buses in Closed Road Networks

Existing green wave control methods for passenger cars and buses mainly focus on maximizing bandwidths at the arterial level. There is little research on green wave control for both at the closed road network level, which makes it difficult to improve the efficiency of the entire area. To address this, a green wave control model that considers both passenger cars and buses in closed road networks is presented in this paper. The objective function of the model is to maximize the sum of the weighted bandwidths of passenger cars and buses on each segment of the road network. The relationships between car green bands, bus green bands, offsets, phase sequences, red time, green time, etc. are analyzed on the level of arterials and road networks, respectively, using time–space diagrams. Based on these analyses, the key constraints of the model are constructed accordingly. In addition, 0/1 variables and a sufficiently large positive number M are introduced to relax some of the constraints to ensure that the presented model has feasible solutions. The results of the numerical example demonstrate that compared with the fixed phase sequence schemes 1, 2, and 3, the total weighted bandwidth generated by the presented model increased by 9.5%, 16.4%, and 17%, respectively. Compared with the model without constraint relaxation, the presented model can still find a global, optimal solution when the common cycle time is fixed, while the model without constraint relaxation has no feasible solution.

Green innovation ecosystem evolution: Diffusion of positive green innovation game strategies on complex networks

The essence of the evolution of the green innovation ecosystem is the process by which the positive strategy of green innovation spreads in a complex network. In this study, the "Object-Technology-Environment-Management-Culture (OETMC)" structure paradigm of innovation ecosystems is presented, and a causal analysis framework of green innovation ecosystem evolution based on green innovation behavior strategy, supported by green innovation efficiency and focused on green innovation ecosystems is developed. Based on this framework, the structure of the green innovation ecosystem and the diffusion process of positive green innovation in the network are discussed. The results reveal the following. (1) The complexity of the green innovation ecological network has visibly improved, but numerous blank connections remain. These are the key constraints that hinder structural evolution. (2) The appearance of a large number of long-range connections weakens the constraint of geographical distance but also hinders edge nodes from joining the network. (3) The existence of preference attachment and power law distribution of the green innovation ecological network leads to the incomplete convergence of positive green innovation strategy at any initial strategy ratio. (4) Default cost and pollution tax rate ensure the enthusiasm of green innovation actors to seek innovation cooperation by increasing opportunity costs, thus accelerating the formation and reconstruction of the green innovation ecological network. These conclusions provide a decision-making reference for governments to encourage green innovation subjects to formulate targeted policies.

An experimental parametric study assessing the effect of a certain initial geometric imperfection on cylinder buckling

Given the sensitivity of axially-loaded cylinder buckling to geometric imperfections, the advent of additive manufacturing provides a compelling platform to assess subtle changes in initial configuration from an experimental perspective. The cylindrical form is ubiquitous in many load-bearing contexts, from soda cans to submarines to rocket fuel tanks. Despite the relative simplicity of the shape, it is striking how the assessment of buckling loads continues to pose strong challenges to the designers of these load-bearing components, often in a situation where weight-saving is a key constraint. Furthermore, this type of buckling typically corresponds to a sudden, severe, catastrophic event, and in addition to posing serious consequences in practice, this also presents challenges for those conducting high-fidelity experiments, especially in terms of repeatability. Any conditions that deviate from a pristine cylindrical shape, and purely axial loading, are the root-cause of the buckling variability. Typically, the slight deviations from the pristine (perfect) conditions are somewhat random and unpredictable in nature. 3D-printing now provides the experimentalist with the ability to produce cylindrical specimens to a very high degree of geometric fidelity, thus allowing a degree of control of the form of subtle geometric imperfections. This paper focuses attention on a specific form of deviation from a pristine cylindrical shape, in which the longitudinal sides follow a mild cosine wave form. The amplitude of this shape is varied (in both directions, i.e., inwards and outwards), and its effect on both the buckling load and buckling mode shape assessed experimentally, using the outcome of finite element analysis as a guide.

FOSTERING COMPETITIVE ENVIRONMENTS FOR ENTREPRENEURS: INSIGHTS AND BEST PRACTICES

Today, it is critical fostering competitive environments in nurturing entrepreneurial success. In an era characterized by dynamic market landscapes, this study delves into key insights and best practices that contribute to creating an ecosystem conducive to the growth and sustainability of entrepreneurial ventures. This research investigates the challenges and perspectives in fostering a competitive environment for entrepreneurship, focusing on individual and institutional barriers faced by entrepreneurs. Drawing on a combination of qualitative data from semi-structured interviews and insights from existing literature, the study identifies key constraints such as regulatory barriers, legal uncertainties, financial challenges, human resource management issues, and inner fears and insecurities among entrepreneurs. Through a systematic analysis, the research proposes recommendations for policymakers and stakeholders to address these constraints and create a conducive environment for entrepreneurial activity. These recommendations include simplifying regulatory procedures, enhancing financial support mechanisms, improving talent development programs, fostering a supportive organizational culture, and combating corruption effectively. The study emphasizes the importance of a holistic approach that addresses both individual and institutional barriers to entrepreneurship, highlighting the need for collaboration between the public and private sectors. By implementing these recommendations, countries can unlock entrepreneurial potential, drive innovation, and achieve sustainable economic development. Keywords: entrepreneurial activity, competitive environment, challenges, solution, Kazakhstan.

“This is an illness. No one is supposed to be treated badly”: community-based stigma assessments in South Africa to inform tuberculosis stigma intervention design

BackgroundThough tuberculosis (TB)-related stigma is a recognized barrier to care, interventions are lacking, and gaps remain in understanding the drivers and experiences of TB-related stigma. We undertook community-based mixed methods stigma assessments to inform stigma intervention design.MethodsWe adapted the Stop TB Partnership stigma assessment tool and trained three peer research associates (PRAs; two TB survivors, one community health worker) to conduct surveys with people with TB (PWTB, n = 93) and caregivers of children with TB (n = 24) at peri-urban and rural clinic sites in Khayelitsha, Western Cape, and Hammanskraal, Gauteng Province, South Africa. We descriptively analyzed responses for each stigma experience (anticipated, internal, and enacted), calculated stigma scores, and undertook generalized linear regression analysis. We conducted 25 in-depth interviews with PWTB (n = 21) and caregivers of children with TB (n = 4). Using inductive thematic analysis, we performed open coding to identify emergent themes, and selective coding to identify relevant quotes. Themes were organized using the Constraints, Actions, Risks, and Desires (CARD) framework.ResultsSurveys revealed almost all PWTB (89/93, 96%) experienced some form of anticipated, internal, and/or enacted stigma, which affected engagement throughout the care cascade. Participants in the rural setting (compared to peri-urban) reported higher anticipated, internal, and enacted stigma (β-coefficient 0.72, 0.71, 0.74). Interview participants described how stigma experiences, including HIV intersectional stigma, act individually and together as key constraints to impede care, leading to decisions not to disclose a TB diagnosis, isolation, and exclusion. Stigma resilience arose through the understanding that TB can affect anyone and should not diminish self-worth. Risks of stigma, driven by fears related to disease severity and infectiousness, led to care disengagement and impaired psychological well-being. Participants desired counselling, identifying a specific role for TB survivors as peer counselors, and community education.ConclusionsStigma is highly prevalent and negatively impacts TB care and the well-being of PWTB, warranting its assessment as a primary outcome rather than an intermediary contributor to poor outcomes. Multi-component, multi-level stigma interventions are needed, including counseling for PWTB and education for health workers and communities. Such interventions must incorporate contextual differences based on gender or setting, and use survivor-guided messaging to foster stigma resilience.

Physics-informed data-driven discovery of constitutive models with application to strain-rate-sensitive soft materials

AbstractA novel data-driven constitutive modeling approach is proposed, which combines the physics-informed nature of modeling based on continuum thermodynamics with the benefits of machine learning. This approach is demonstrated on strain-rate-sensitive soft materials. This model is based on the viscous dissipation-based visco-hyperelasticity framework where the total stress is decomposed into volumetric, isochoric hyperelastic, and isochoric viscous overstress contributions. It is shown that each of these stress components can be written as linear combinations of the components of an irreducible integrity basis. Three Gaussian process regression-based surrogate models are trained (one per stress component) between principal invariants of strain and strain rate tensors and the corresponding coefficients of the integrity basis components. It is demonstrated that this type of model construction enforces key physics-based constraints on the predicted responses: the second law of thermodynamics, the principles of local action and determinism, objectivity, the balance of angular momentum, an assumed reference state, isotropy, and limited memory. The three surrogate models that constitute our constitutive model are evaluated by training them on small-size numerically generated data sets corresponding to a single deformation mode and then analyzing their predictions over a much wider testing regime comprising multiple deformation modes. Our physics-informed data-driven constitutive model predictions are compared with the corresponding predictions of classical continuum thermodynamics-based and purely data-driven models. It is shown that our surrogate models can reasonably capture the stress–strain-strain rate responses in both training and testing regimes and improve prediction accuracy, generalizability to multiple deformation modes, and compatibility with limited data.

How to indigenise the blue economy in Aotearoa New Zealand

ABSTRACT Māori, as substantial stakeholders in the fishery sector, must play a major role in any imagined or proposed transition to a blue economy. This paper provides the results from a project examining how to indigenise the blue economy in Aotearoa New Zealand, outlining the underlying theory and providing results from five case studies. The paper explores three key thematic constraints identified in consultation with the Māori fishing sector, namely: centralisation of power; quota fragmentation; and product commodification. It concludes that there is a need to focus on: redressing the imbalance between iwi and hapū by providing quota for hapū while providing wrap around financial and capacity support, incorporating local experts in decision making, and creating community clusters; overcoming fragmentation through joint ventures and hybrid governance structures and a focus on quota optimisation; and increasing market differentiation through research, innovation, and branding and marketing initiatives.

Agricultural Commodity Markets in Pakistan: Analysis of Issues

EXECUTIVE SUMMARY Agriculture markets in Pakistan are still primarily based on a colonial-era model and have not modernised with changing times. This has increased unnecessary costs in the supply chains that put growers and end-consumers at a disadvantage. Additionally, price and supply volatility causes insecurity for policy-makers as information about prices, supply and demand is not structured, timely or reliable. For decades, agricultural markets have functioned without government focus on innovation. Recent initiatives from various federal and provincial agencies provide hope that this vital area can now finally be addressed. Numerous constraints need to be resolved to bring meaningful change to the ecosystem. The process must start with a fresh policy look and commitment to adopt modern themes. This policy process can be supported by technology and successful lessons from other countries as well as developments in other sectors within the country. There is a need to develop a certain level of coordination between various federal and provincial agencies. The increasingly fragmented nature of agriculture markets might be useful for some stakeholders as they can innovate according to their needs but it leaves most of the sector at a continually suboptimal level. The lack of progress in modernising core markets has also made it difficult for some innovative solutions to succeed. A rapid assessment of the current environment, key constraints and recommendations for possible development areas is presented in this report.

Atacama Large Aperture Submillimeter Telescope (AtLAST) science: Resolving the hot and ionized Universe through the Sunyaev-Zeldovich effect

An omnipresent feature of the multi-phase “cosmic web” — the large-scale filamentary backbone of the Universe — is that warm/hot (≳ 105 K) ionized gas pervades it. This gas constitutes a relevant contribution to the overall universal matter budget across multiple scales, from the several tens of Mpc-scale intergalactic filaments, to the Mpc intracluster medium (ICM), all the way down to the circumgalactic medium (CGM) surrounding individual galaxies, on scales from ∼ 1 kpc up to their respective virial radii (∼ 100 kpc). The study of the hot baryonic component of cosmic matter density represents a powerful means for constraining the intertwined evolution of galactic populations and large-scale cosmological structures, for tracing the matter assembly in the Universe and its thermal history. To this end, the Sunyaev-Zeldovich (SZ) effect provides the ideal observational tool for measurements out to the beginnings of structure formation. The SZ effect is caused by the scattering of the photons from the cosmic microwave background off the hot electrons embedded within cosmic structures, and provides a redshift-independent perspective on the thermal and kinematic properties of the warm/hot gas. Still, current and next-generation (sub)millimeter facilities have been providing only a partial view of the SZ Universe due to any combination of: limited angular resolution, spectral coverage, field of view, spatial dynamic range, sensitivity, or all of the above. In this paper, we motivate the development of a wide-field, broad-band, multi-chroic continuum instrument for the Atacama Large Aperture Submillimeter Telescope (AtLAST) by identifying the scientific drivers that will deepen our understanding of the complex thermal evolution of cosmic structures. On a technical side, this will necessarily require efficient multi-wavelength mapping of the SZ signal with an unprecedented spatial dynamic range (from arcsecond to degree scales) and we employ detailed theoretical forecasts to determine the key instrumental constraints for achieving our goals.

Experimental examination on electrochemical machining of Mg/FeCoCrNiMn composite

ABSTRACT The current study explores the effectiveness of the ECM process when machining newly developed high entropy alloy (HEA)-reinforced magnesium composites. To evaluate the machinability, the study focuses on two key output constraints: surface roughness (Ra) and material removal rate (MRR). Experimental trials involve adjusting variables such as feed rate (FR), current, Electrolyte concentration (EC), & voltage in which experiment design is done through Taguchi method. Results highlights voltage as the most important input parameter governing Ra, followed by current. Similarly, voltage emerges as the primary influencer for MRR, with current being the second most influential. Furthermore, artificial neural networks (ANN) yielded predictions closely aligns with the experimental data. The optimal parameter set identified through CRITIC-WASPAS method included 5 Wt.% HEA, 15 V Voltage, 2 Amps current, 0.3 mm/min feed, and 25 g/lit electrolyte concentrations, resulting in a surface finish of 3.47 µm and a production rate of 0.039 mg/min.

Public transportation means as seen by citizens: Approaching the case of the Dominican Republic

Especially in lowand middle-income countries, key constraints such as dense traffic flows, jams, and pollution constitute frequent issues that potentially explain many negative consequences in terms of (e.g.) efficiency, sustainability, and mobility safety. In this regard, recent evidence supports the idea that fostering public transportation is crucial to offering solutions for this difficult panorama. However, transport mode-related choices and shifts have been proven to depend highly on key perceptions and needs of potential users. The aim of this study was to analyze a set of key users’ perceptions, usage, and perceived quality of public transportation in the Dominican Republic, as well as to explore the most relevant features for Dominicans from the “desired quality” paradigm. For this research at a national level, data retrieved from a nationwide sample of 1254 inhabitants of the Dominican Republic was used, proportional to the ONE census in terms of sex, age, habitat, and region. Overall, the results show that the general quality of transportation is 6.70 points out of 10. The use of public transportation in the Dominican Republic has a medium-low rating and is very focused on urban buses (41 %) and public cars (27.1 %). Nonetheless, the metro remains the most highly rated means of transport (M = 8.75). Concerning the quality variables analyzed, the highest scores are for accessibility (M = 7.08) and frequency of service (M = 6.99). Further, Dominicans focus on improving comfort, vehicle conditions, and safety. This study constitutes a first approximation to the desired quality of public transportation for Dominican Citizens, which may help policymakers scope user-based needs in public transportation systems and encourage a more frequent (and friendlier) public transport use in the country.