Tandem Bicycle Research Articles

Fen-Orchids, a Garden, and a Tandem in the (Post-)Jungle: Unsettling Care and Control in the European Borderscape

The purpose of this article is to unsettle and thicken the increasing attention that has recently been given to care in design research. I do this by looking to both the contents and the conditions of making a two-screen video with a tandem bicycle in the so-called “Jungle” refugee camp in Calais, northern France, and in the eco-park that replaced the camp after it was cleared. In doing so, I make two arguments. First, that care for nature in the camp is simultaneously a form of control over access to the space. Second, using the tandem as an example, I discuss a speculative approach to care that is concerned with consequences and possibilities by designing vulnerability into objects. In doing so, the article foregrounds critical approaches to care in speculative design research, conceptualizing care beyond normative assumptions of inherent “goods” to tune in to the complex and troubling political and ecological relations that certain care practices produce.

Loading and structural stiffness of tandem bicycle frames

Tandem bicycles are used for all para-cycling events for visually impaired athletes. Tandems are structurally more challenging to design than solo bicycles: they must resist higher loading over a longer wheelbase, yet must still fit between the legs of the riders. Despite this, there is limited published work on tandem design. This paper presents a method for determining maximal loading of a tandem bicycle frame in racing scenarios. The only inputs required are the dimensions of the frame and the torques exerted by the riders. Outputs are the forces acting on the frame. The method is used to provide loads for structural analyses of tandem frames of different topologies. Twisting of the frame under a starting effort is shown to be the worst load case. The “double diamond” is shown to be the most efficient tubular frame design, on a stiffness per weight basis, but is only 2% superior to an “open” topology.

Power loss of the chain drive in a race tandem bicycle

Tandem cycling is a paralympic discipline, in which two cyclists ride on one tandem bicycle. Their performance can be improved by minimizing power losses. This study aimed to quantify power loss due to the chain drive of a tandem bicycle and influence of power input, location of power input, and rear chain wheel size. Power loss was determined by the difference between power input applied on the cranks (front or back rider) and power output measured at the rear wheel. Power output values were set from 100 to 400 W, with 50 W increments, and using two gear ratios, 53-11 and 53-13. Power input was generated at the back crank (with only the primary chain—solo bicycle—and with primary and secondary chain attached) and at the front crank (with primary and secondary chain attached). The power loss for the solo bicycle was 2.1% (± 1.5%). A significantly larger power loss was found for the tandem in the back (3.7 ± 2.4%, p < 0.001) and front positions (3.0 ± 1.8%, p < 0.001), with marginal differences between positions at higher power output. Power loss for the tandem was lower with gear 53-13 (2.9% ± 1.7%) compared to 53-11 (4.0 ± 2.8%, p < 0.001, effect size is medium). Therefore, findings suggest that back and front riders experience similar power losses due to the chain drive, but more than on a solo bicycle. Tandem cyclists can reduce their power loss in the chain drive by selecting larger gear ratios. Coaches may consider these findings for selecting and coaching their tandem cyclists.

SoTL in Human Movement Sciences: Moving Forward in South Africa

The Scholarship of Teaching and Learning (SoTL) is an emerging focus within South Africa (SA). In Human Movement Sciences (HMS) in SA, research is primarily discipline-specific, and many researchers are unfamiliar with SoTL. To explore how we (as HMS lecturers) could integrate SoTL into our research, we formed a community of practice (CoP). The SoTL unicycle depiction of Swart et al. (2016) suited our visual analogy since the focus of HMS is on the human body that is in motion. For us, the unicycle represented HMS SoTL in motion. Swart et al. (2016) viewed the SoTL movement as an academic’s individual journey, whereas we saw SoTL from a CoP perspective. Therefore, we adapted the unicycle into a tandem bicycle, representing our collaborative engagements. Participatory action learning and action research (PALAR) formed our theoretical framework. Through our dialogue, each tandem wheel’s focus emerged. The back wheel was about deciding to SoTL (or not). This became a linchpin of our critical dialogue during the relationship-building phase of our CoP. Once we committed, we needed to learn how to keep our CoP moving forward. This became the middle wheel of our tandem bicycle. Next, the front wheel and handlebar became our guide into what the future of SoTL would be for us. The tandem bicycle, therefore, represents our collective cycles of learning as we became SoTL researchers. We believe our learning can support others transitioning from discipline-specific research to engaging in SoTL. *Please note that this poster is best viewed in Adobe on a computer/laptop for interactivity. Click here to read the corresponding ISSOTL blog post.

Capturing the Complexities of Collaborative Partnerships in Early Childhood Through Metaphor

AbstractWithin an early childhood setting strong collaborative partnerships between the service and the family are critical to the success of a child’s development and learning. Collaborative interactions with families are considered indicators of quality within early childhood services. Whilst the value and importance of collaborative partnerships are widely agreed upon, the plethora of terms utilised to describe collaborative partnerships, and the multitude of models for its enactment have muddied the waters for successful interpretation and application in practice. This paper employs metaphor as a way of creating conceptual clarity of the complex issues surfaced in the literature related to collaborative partnerships and their intended implementation in curriculum and policy, and what practices occur in services globally. Findings highlight a mismatch between discourse and practice and elucidate the missed opportunities for collaborative partnerships towards improving service quality. Insights identified in this paper are relevant to the early childhood sector, highlighting a call for further clarity and interpretation of the term and mechanisms of quality collaborative partnership to inform practices in the field. This paper suggests new ways of thinking that rupture taken for granted viewpoints, offering the metaphor of a tandem bicycle to reflect the collaborative partnership between educators and families. This article provides a powerful provocation for the early childhood field to encourage reflection and refinement to existing conceptualisations of family-educator relationships.

Sulfonyl radical-triggered two/three-component tandem bicyclization of CN-containing 1,6-enynes under transition metal- and base-free conditions

Sulfonyl radical-triggered two/three-component tandem bicyclization of CN-containing 1,6-enynes.

"Baby, You can Ride my Bike"

We envision a future where self-driving bicycles can take us to our destinations. This allows cyclists to use their time on the bike efficiently for work or relaxation without having to focus their attention on traffic. In the related field of self-driving cars, research has shown that communicating the planned route to passengers plays an important role in building trust in automation and situational awareness. For self-driving bicycles, this information transfer will be even more important, as riders will need to actively compensate for the movement of a self-driving bicycle to maintain balance. In this paper, we investigate maneuver indications for self-driving bicycles: (1) ambient light in a helmet, (2) head-up display indications, (3) speech feedback, (4) vibration on the handlebar, and (5) no assistance. To evaluate these indications, we conducted an outdoor experiment (N = 25) in a proposed tandem simulator consisting of a tandem bicycle with a steering and braking control on the back seat and a rider in full control of it. Our results indicate that riders respond faster to visual cues and focus comparably on the reading task while riding with and without maneuver indications. Additionally, we found that the tandem simulator is realistic, safe, and creates an awareness of a human cyclist controlling the tandem.

The aerodynamic assessment of tandem cyclists in preparation for the 2021 Paralympic Games: A case study

Reducing the level of aerodynamic drag (CdA) via use of a wind tunnel will ultimately improve a competitive cyclists performance. Whilst this tool is widely considered a ‘gold standard’, previous studies have centred on single riders or scale models to evaluate aerodynamic drag. No study to date has assessed the precision of wind tunnel testing with the additional perceived complexity of a tandem bicycle with a pair of competitive paracyclists. The first part of this investigation evaluated the use of a wind tunnel in the assessment of tandem paracyclists. A male and female team of paracyclists riding tandem versions of either a time trial track bicycle or a road/time trial bicycle undertook a series of measurement intervals in a wind tunnel. Three different combinations of these riders and bicycles obtained a Coefficient of Variation of their mean CdA of 1.8%–2.6%. The second part of this investigation acted as a case study by implementing a range of aerodynamic interventions to potentially reduce the male team’s CdA. For example, progressive efforts reduced a team’s CdA from the baseline of 0.338 m2 to ultimately 0.321 m2 predominately by lowering both tandem riders heads Whilst tandem cyclist performance enhancement has recieved scant attention in the past, this case study only highlights the value of doing so in the future.

Learning about the European borderscape on a tandem bicycle

Learning about the European borderscape on a tandem bicycle

Radical Tandem Bicyclization Triggered by the α-Position of α,β-Unsaturated Ketones Bearing Nonterminal 1,6-Enynes: Synthesis of the 5H-Benzo[a]fluoren-5-one Skeleton.

A novel method for the synthesis of 5H-benzo[a]fluoren-5-one from inactive nonterminal 1,6-alkynes through a free radical tandem bicyclization process has been established. This process achieved a continuous cyclization triggered rarely by the α-position of α,β-unsaturated ketones. The reaction constructed three C-C bonds in one step with the readily accessible substrates and excellent substrate compatibility.

Effect of a High-Intensity Tandem Bicycle Exercise Program on Clinical Severity, Functional Magnetic Resonance Imaging, and Plasma Biomarkers in Parkinson's Disease.

Rationale: The optimal modality, intensity, duration, frequency, and dose–response of exercise as a therapy for Parkinson's Disease (PD) are insufficiently understood.Objective: To assess the impact of a high-intensity tandem bicycle program on clinical severity, biomarkers, and functional MRI (fMRI) in PD.Methods: A single-center, parallel-group clinical trial was conducted. Thirteen PD patients aged 65 or younger were divided in two groups: a control group and an intervention group that incorporated a cycling program at 80% of each individual's maximum heart rate (HR) (≥80 rpm), three times a week, for 16 weeks. Both groups continued their conventional medications for PD. At baseline and at the end of follow-up, we determined in all participants the Unified Parkinson's Disease Rating Scale, anthropometry, VO2max, PD biomarkers, and fMRI.Results: VO2max improved in the intervention group (IG) (+5.7 ml/kg/min), while it slightly deteriorated in the control group (CG) (−1.6 ml/kg/min) (p = 0.041). Mean Unified Parkinson's Disease Rating Scale (UPDRS) went down by 5.7 points in the IG and showed a small 0.9-point increase in the CG (p = 0.11). fMRI showed activation of the right fusiform gyrus during the motor task and functional connectivity between the cingulum and areas of the frontal cortex, and between the cerebellar vermis and the thalamus and posterior temporal gyrus. Plasma brain-derived neurotrophic factor (BDNF) levels increased more than 10-fold in the IG and decreased in the CG (p = 0.028). Larger increases in plasma BDNF correlated with greater decreases in UPDRS (r = −0.58, p = 0.04).Conclusions: Our findings suggest that high-intensity tandem bicycle improves motor function and biochemical and functional neuroimaging variables in PD patients.Trial registration number: ISRCTN 13047118, Registered on February 8, 2018.

Rh(III)-Catalyzed Tandem Bicyclization of 2-Arylimidazo[1,2-a]pyridines with Cyclic Enones for the Construction of Bridged Scaffolds.

An efficient Rh(III)-catalyzed bicyclization of 2-arylimidazo[1,2-a]pyridine with cyclic enones has been developed for the synthesis of bridged imidazopyridine derivatives in excellent yields up to 95%. The reaction proceeds through a sequential conjugate addition of ortho-C-H bond of aryl group followed by an intramolecular C3-alkylation of imidazopyridine ring in a highly regioselective manner.

GROUPS CAN KNOW HOW

Abstract One can know how to ride a bicycle, play the cello, or collect experimental data. But who can know how to properly ride a tandem bicycle, perform a symphony, or run a high-energy physics experiment? Reductionist analyses fail to account for these cases strictly in terms of the individual know-how involved. Nevertheless, it doesn’t follow from non-reductionism that groups possess this know-how. One must first show that epistemic extension cannot obtain. This is the idea that individuals can possess knowledge even when others possess some of the epistemic materials (e.g. evidence possessed, abilities exercised) generating it. I show that only knowledge-that can be epistemically extended, not knowledge-how. Appeal to epistemic extension is a viable way of avoiding group knowledge-that ascriptions but not group knowledge-how ascriptions. Therefore, groups can know how.

On the effects of crosswinds in tandem aerodynamics:An experimental and computational study

Abstract Aerodynamics has been an important research aspect in cycling science, with aerodynamic apparel and equipment, athlete postures, and race strategies all taking advantage of scientific aerodynamics knowledge. Crosswinds occur when cyclists travel at a non-zero angle to the direction of the wind. Research into crosswinds has yielded race strategies for able-bodied cyclists such as staggered drafting, and wind conditions are recognised as a key factor to consider for cyclist safety. The impact of crosswinds on tandem para-cyclists is less understood. Within the tandem para-cycling discipline, two athletes compete as a team on a single bicycle with a high degree of flow interaction between both athletes. Wind tunnel experiments and computational fluid dynamics were utilised in this research to investigate the drag and lateral forces at yaw angles between 0°–20°. No single turbulence model was found superior for all yaw angles investigated, with the SST k- ω and k-kl- ω turbulence models providing good results for separate yaw ranges. The individual drag and lateral forces experienced by both athletes and the tandem bicycle were investigated to provide further clarity on the distribution of wind loads for each yaw angle tested, and to aid in identifying potential locations for aerodynamic optimisation. 15° yaw was found to be the critical yaw angle where the maximum drag area of 0.337 m2 was experienced. The lateral force exceeded the drag force by 52.8% at a yaw angle of 20°.

Acid-Promoted Bicyclization of Diaryl Alkynes: Synthesis of 2 H-Indazoles with in Situ Generated Diazonium Salt as Nitrogen Source.

An unprecedented transition-metal-free tandem bicyclization of diaryl alkynes has been disclosed, which provides a streamlined access to a range of polycyclic 2 H-indazoles in high to excellent yields. The salient features of this reaction include readily available starting materials, good functional group compatibility, mild reaction conditions, no column chromatography, high bond-formation efficiency, and ease in further transformations. Notably, this is the first example for the synthesis of 2 H-indazoles with in situ generated diazonium salt as the nitrogen source, and a mechanistic rationale involving an acid-promoted tandem diazonium salt formation/bicyclization process is discussed.

Aerodynamic drag in competitive tandem para-cycling: Road race versus time-trial positions

An athlete's riding posture is a key element for aerodynamic drag in cycling. Tandem cycling has the complication of having two athletes in close proximity to each other on a single tandem bicycle. The complex flow-field between the pilot and stoker in tandem cycling presents new challenges for aerodynamic optimisation. Aerodynamic drag acting on two tandem road race setups and two track time-trial setups were analysed with computational fluid dynamics (CFD) simulations. For validation purposes, wind tunnel measurements were designed providing drag measurements from both tandem athletes simultaneously using a quarter-scale model. A max drag force deviation of 4.9% was found between the wind tunnel experiments and CFD simulations of the quarter-scale geometry. Full-scale CFD simulations of upright, crouched, time-trial and frame-clench tandem setups were performed. The drag force experienced by individual athletes in all investigated tandem setups was compared to that of solo riders to enhance understanding of the aerodynamic interaction between both tandem athletes. The most aerodynamic tandem setup was found to be the frame-clench setup which is unique to tandem cycling and had a CDA of 0.286 m2, and could provide an advantage of 8.1 s over a standard time-trial setup for a 10 km time-trial event.

Changes in physiological responses to tandem bicycle exercise during the 5 hour endurance race in Okayama International Circuit.

Changes in physiological responses to tandem bicycle exercise during the 5 hour endurance race in Okayama International Circuit.

Bicyclization of Azomethine Ylide: Access to Highly Functionalized 3H-Pyrrolo[2,3-c]quinolines.

A tandem bicyclization of azomethine ylides with methyleneaminochalcones was developed for the straightforward and facile synthesis of 2-substituted polyfunctionalized pyrrolo[2,3-c]quinolines. Both an unusual reactivity profile of azomethine ylide and a novel strategy for the construction of the tricyclic framework by the successive construction of the pyridine and pyrrole rings were exhibited in this domino reaction. Two intermediates are isolated in the control experiments, and thus a tandem bicyclization/elimination/oxidative aromatization process is proposed for the reaction mechanism.

A Tandem Cycling Program: Feasibility and Physical Performance Outcomes in People With Parkinson Disease.

Individuals with Parkinson disease (PD) have motor and nonmotor impairments that interfere with exercise participation. The purpose of this study was to examine the feasibility and physical performance outcomes of a community-based indoor tandem cycling program that was designed to facilitate a higher cadence, consistency, and intensity of training. Forty-one participants with mild to moderate PD were enrolled. A high-cadence cycling protocol using mechanically augmented (or forced) exercise on a tandem bicycle was adapted for our program. Participants cycled 3 times per week for 10 weeks. Feasibility measures included program retention, attendance, and adverse events, as well as the ability to reach training goals for heart rate (HR) and cadence. Physical performance outcomes included the Berg Balance Scale (BBS), Short Physical Performance Battery (SPPB), Five-Times-Sit-to-Stand (FTSTS) Test, Timed Up and Go (TUG), and gait parameters during usual and fast-paced walking. Program feasibility was demonstrated with a high attendance rate (96%) and retention rate (100%). There were no adverse events. The majority of participants reached their exercise training goals for target HR (87%) and cadence (95%). Statistically significant physical performance improvement (P < 0.05) was observed across domains of gait, balance, and mobility, suggesting a slowing or reversal of functional decline as a result of this cycling program. Program feasibility and improved physical performance outcomes were demonstrated in individuals with mild to moderate PD participating in a community-based indoor tandem cycling program.Video Abstract available for more insights from the authors (see supplemental digital content 1, http://links.lww.com/JNPT/A146).

Tandem Prins Cyclization for the Stereoselective Synthesis of Bridged Benzopyran Derivatives

AbstractA tandem bicyclization strategy has been developed for the stereoselective synthesis of 3,4‐dihydro‐2 H,6H‐2,6‐methanobenzo[b][1,5]dioxocine derivatives in good yields and selectivities through the cyclocondensation of 2‐(1‐hydroxy‐3‐methylbut‐3‐en‐1‐yl)phenol with various aldehydes by using 10 mol % BF3⋅OEt2. This is the first reported stereoselective construction of a bridged tricyclic skeleton through a cascade Prins cyclization procedure. This process constitutes an elegant strategy for the quick construction of tricyclic architectures in a single step.