Suspended System Research Articles

A modified trap design for sampling subterranean habitats for central Texas Eurycea salamanders

In this paper, we describe modifications to a sampling technique for surface, stream-dwelling salamanders for use in subterranean settings. Leaf litter bags are an effective and commonly used trap for salamanders, and their construction purposefully allows animals to move freely in and out of the trap. However, this presents a problem in subterranean deployment because retrieving the trap over long vertical distances, such as well sampling, allows time and space for the animals to escape. To overcome this challenge, we enclosed a leaf litter bag in a suspended net system contained by a lanyard to sample a 3-meter deep well. Our trap modifications resulted in the live capture of adult and immature federally threatened Salado Salamanders (Eurycea chisholmensis) from the well in addition to aquatic invertebrates. This represents a novel trapping technique within a habitat system for which stygofauna sampling options are limited.

Test-Based Assessment of the Seismic Response of Bracing Systems for Concealed Grid Suspended Ceilings

ABSTRACT Despite not directly contributing to a structure’s load-bearing capacity, non-structural elements like partitions, cladding, ceilings, floor finishes, and facades play a pivotal role in the overall building design and occupant safety. Their susceptibility to damage during seismic events, however, can lead to substantial economic losses, business interruptions, and potential risks to occupants. Focusing on concealed grid suspended ceiling systems, this study focuses on enhancing their seismic resilience introducing and experimentally evaluating two innovative bracing systems (Typology N and Typology W) that utilize steel members, already used in non-seismic application, as braces. Unlike prior research using shake tables, this study employs a specially designed set-up on a universal testing machine, offering a cost-effective and efficient approach for cyclic testing and considering the spatial variability of seismic loads. As a complementary task, component-level tests were conducted on the compressed strut to extend the results for suspended ceiling systems having suspension height up to 2 meters. The results show that Typology N performs better than Typology W, with 1.7 times greater resistance and 2.5 times greater stiffness on average, demonstrating the importance of considering different directions of horizontal seismic loading in the performance assessment. The study provides valuable insights, including design resistance values and a step-by-step procedure for determining the maximum ceiling area that a single bracing system can cover, aiding in optimizing bracing system selection and mitigating seismic vulnerability in concealed grid suspended ceilings for seismic-prone regions.

Simultaneous nitrification and denitrification framework for decentralized systems: Long-term study utilizing rope-type biofilm media under field conditions

This research introduces a novel approach to achieve simultaneous nitrification-denitrification (SND) under dynamic load conditions using a cost-effective rope-type biofilm technology. The approach represents a significant advancement in wastewater treatment, particularly beneficial for remote and decentralized communities. The biofilm-based SND process was developed using a pilot-scale flow-through reactor by implementing upstream carbon management with constant-timer-based aeration control versus dynamic-sensor-based aeration control strategies. The findings indicate that adding an upstream anaerobic pretreatment process to handle excess carbon plays a substantial role in achieving a sustainable SND process under a dynamic load environment using simple aeration on-off control. The most optimal nitrification performance of 0.32 g NH3-N/m2/d (89 % removal) was achieved under a 1-hour ON/30-minute OFF aeration. The process sustained an average bulk liquid DO of 5.16 mg/L and 3.80 mg/L during the aeration ON and OFF periods, respectively, facilitating a 0.13 g N/m2/d (41 %) total inorganic nitrogen (TIN) removal, notably, implementing advanced aeration strategies driven by DO, NH3, and NO3 sensors enhanced TIN removal efficiency to 72 %. The nitrification performance remained comparable (89 % removal), resulting in 3 and 10 mg N/L effluent ammonia and TIN concentration, respectively. Additionally, utilizing two multivariate approaches accounting for 82 % and 64 % of the variance, this study discerned patterns in monitored variables and performance. Additionally, the analysis underscored the difference of bulk liquid DO levels in the biofilm versus suspended systems inhibiting the SND process. Distinct bacterial communities were established in biofilms under aerobic, anaerobic, and SND conditions, with the SND reactor showing a hierarchy of functional group and enzymes, enriched sequentially from heterotrophs to denitrifiers, nitrifiers, and anammox bacteria. These innovations underline the potential of tailored control strategies to enhance a passive biofilm-based SND process efficiency under dynamic conditions, providing scalable solutions for diverse target water quality demands in remote communities and decentralized systems.

Sub‐assemblage testing and fragility analysis of connections of continuous‐plasterboard suspended ceiling systems

AbstractPast earthquake reconnaissance reports highlighted extensive seismic damages to suspended ceiling components and connections, including instances of complete ceiling failures. The seismic qualification of these nonstructural elements typically requires comprehensive evaluation through full‐scale shake table testing. However, such experimental evaluation is ordinarily not possible for every change made in various components and connections of ceiling systems due to the cost and effort involved. A feasible alternative is to obtain the behavior of components and connections from sub‐assemblage testing and incorporate them in appropriate numerical ceiling models to derive mechanical responses for developing alternative or new installation schemes. This paper considers critical connections of three continuous‐plasterboard suspended ceiling systems that were evaluated using shake table‐generated motions. The connections were classified according to their attachment to typical floors and walls of building structures, and sub‐assemblage testing was conducted using both monotonic and cyclic displacement loading. The observed failure modes in each connection were detailed, and appropriate damage states were assigned as the basis for constructing connection fragility curves. The results of the sub‐assemblage testing were presented in terms of the hysteresis responses, envelope curves, nonlinear backbone curves, and cumulative energy dissipation curves. Additionally, multilinear models of the connections were derived by approximating nonlinear backbone curves’ initial‐ and post‐yield behaviors. These multilinear models were further idealized to derive three equivalent linearized models for simplified yet reasonably accurate results for linear structural analyses. Finally, fragility curves were derived for all connections, considering their cyclic displacement failure capacities.

A differentiation protocol for generating pancreatic delta cells from human pluripotent stem cells.

In this protocol, we detail a seven-stage differentiation methodology for generating pancreatic delta cells (SC-delta cells) from human pluripotent stem cells (hPSCs). In the first step, definitive endoderm is generated by activin A and CHIR99021, followed by induction of primitive gut tube and posterior foregut by treatment with FGF7, SANT1, LDN193189, PdBU, and retinoic acid (RA). The subsequent endocrine generation and directed SC-delta cell induction is achieved by a combined treatment of the FGF7 with FGF2 during stage 4 and 5, together with RA, XXI, ALK5 inhibitor II, SANT1, Betacellulin and LDN193189. The planar cultivation is converted to a suspended system after stage 5, allowing cells to aggregate into delta cell-containing spheroids. The differentiation takes approximately 4-5weeks for delta cell generation and an additional 1-2weeks for cell expansion and evaluation. We believe that this amenable and simplified protocol can provide a stable source of SC-delta cells from efficient differentiation, facilitating further investigation of the physiological role of delta cells as well as refinement of islet cell therapeutic strategies.

3D bioprinting of an intervertebral disc tissue analogue with a highly aligned annulus fibrosus via suspended layer additive manufacture.

Intervertebral disc (IVD) function is achieved through integration of its two component regions: the nucleus pulposus (NP) and the annulus fibrosus (AF). The NP is soft (0.3-5 kPa), gelatinous and populated by spherical NP cells in a polysaccharide-rich extracellular matrix (ECM). The AF is much stiffer (~100 kPa) and contains layers of elongated AF cells in an aligned, fibrous ECM. Degeneration of the disc is a common problem with age being a major risk factor. Progression of IVD degeneration leads to chronic pain and can result in permanent disability. The development of therapeutic solutions for IVD degeneration is impaired by a lack of in vitro models of the disc that are capable of replicating the fundamental structure and biology of the tissue. This study aims to investigate if a newly developed suspended hydrogel bioprinting system (termed SLAM) could be employed to fabricate IVD analogues with integrated structural and compositional features similar to native tissue. Bioprinted IVD analogues were fabricated to recapitulate structural, morphological and biological components present in the native tissue. The constructs replicated key structural components of native tissue with the presence of a central, polysaccharide-rich NP surrounded by organised, aligned collagen fibres in the AF. Cell tracking, actin and matrix staining demonstrated that embedded NP and AF cells exhibited morphologies and phenotypes analogous to what is observed in vivo with elongated, aligned AF cells and spherical NP cells that deposited HA into the surrounding environment. Critically, it was also observed that the NP and AF regions contained a defined cellular and material interface and segregated regions of the two cell types, thus mimicking the highly regulated structure of the IVD.

Dynamic features and wind-resistant strategy of suspended monorail vehicle-track beam systems subjected to turbulent wind

Suspended monorail vehicles (SMV), hung beneath box beams with open bottoms, exhibit significant transverse wobble when exposed to turbulent winds, markedly impacting passenger comfort. This study presents an effective methodology for comprehensively evaluating the dynamical behavior of suspended monorail vehicle-track beam systems (SMVTBS) under wind action. First, based on the multi-rigid body dynamics theory and finite element method, an integrated vehicle-track beam interaction model is established. Then, by applying the auto-regressive (AR) linear filtering method, a turbulent wind velocity field with inherent correlations is adequately simulated through a stochastic process, which is later converted into wind force acting on both the track beam and vehicles. On this basis, the vibration responses of the SMVTBS with and without wind actions are compared, and the effects of the wind load on the vehicle-track beam dynamical behavior are revealed. Furthermore, to improve the wind-resistant performance of the SMV, several crucial design parameters are reasonably selected and effective wind-resistant strategies are proposed. Finally, the dynamic performance of the SMV is evaluated under wind action, and suitable train running speeds were recommended at different wind velocities to guarantee vehicle riding comfort. The research results can provide useful guidance for the design and operation of SMVTBS against crosswinds.

Gain-enhanced suspended optomechanical system with tunable dissipative coupling strength

Active cavity optomechanical system provides an invaluable physical platform for cavity optomechanics research, particularly those involving dissipative coupling, which holds significant potential for advancing the field of quantum physics. In our previous work, an active levitated optomechanical system was established for the first time [Nat. Phys 19, 414 (2023)10.1038/s41567-022-01857-9]. Here we report a gain-enhanced suspended optomechanical system based on the dissipative coupling between the SiN membrane and the intracavity laser. This system has a high dissipative coupling strength which is widely tunable through simple mechanical adjustments. Moreover, the influence of pumping power and the propagation distance of the free-space beam on the maximum effective dissipative coupling strength is comprehensively investigated. Based on the numerical discussion, we propose effective methods to enhance the dissipative coupling experimentally. The active suspended cavity optomechanical system has great potential in realizing the cooling of the membrane to the quantum ground state or heating the membrane to produce phonon lasers, which can be applied to such cutting-edge fields as quantum precision measurements, macroscopic quantum state, and information transmission and processing.

Development and thermal performance testing of radiant conditioning ceiling panels

The past decades have seen an advancement from heavyweight radiant floors to lightweight conditioning ceiling systems. However, the performance of these lightweight systems are seldom comprehensively discussed in an informative manner for designers. This paper reviews lightweight radiant ceiling panel designs and conducts instrumental experiments to examine the thermal performance of different designs. Four distinct capillary hydronic panels have been designed and developed to assesses their thermal performance via empirical testing and measurement. Prototypes were built and integrated into a suspended ceiling system where they were tested in cooling mode. The response time, surface temperature, and energy transfer of the different panel designs were investigated. The experiment results show that higher thermal mass yields higher heat transfer and better surface temperature, but longer response time. A better thermal connection between the capillary tubes and the radiant surface also results in better conduction, faster response times, and improved surface temperature.

Adaptive control of quadrotor suspended load systems with variable payload and wind disturbances

AbstractThis paper introduces an adaptive control scheme for quadrotor suspended load systems, to track desired trajectory with variable payload and wind disturbances. The dynamic model of the quadrotor suspended load system is developed, taking into account the impact of the wind field described by the Dryden model. To attenuate the effects of payload variation and wind disturbances on the system, an adaptive control method based on disturbance observers is devised. Additionally, the uniform boundedness of all error signals is demonstrated. The effectiveness of the designed control method is verified through simulations, which serves to strengthen its applicability in practical applications.

Wind-induced creaking noise assessment of 3D full-scale assemblies of drywall system using multi-axis cyclic testing

The lateral wind load applied to high-rise buildings results in movements that can cause creaking noises in drywall partitions with suspended ceiling systems. These noises can be disruptive to the residents and impair the structure’s serviceability. In this study, a sequence of large-scale three-dimensional (3D) experiments was conducted on two assemblies of drywall partitions with a suspended ceiling system to address this serviceability issue. The goal was to explore the 3D response of these assemblies, with a key emphasis on validating the effectiveness of adhesives in mitigating noise introduced by screw fixings, not only for individual walls but also when interacting with neighbouring walls and ceilings, which represent the real-world conditions. The six-degree of freedom (6-DOF) Multi-Axis Substructure Testing (MAST) system at Swinburne University Technology was used to simulate realistic wind load conditions. Two sets of test specimens were constructed using different methods to fix the plasterboard wall lining to the cold-formed steel (CFS) frame, which was rigidly bolted to both the MAST crosshead and the floor below. The first set of specimens (Assembly 1) had the plasterboards screw-fixed to the steel frame, while the second set (Assembly 2) used adhesive-only or a combination of adhesive and screw-fixing methods. Additionally, the instrumentation employed for acoustic measurements was strategically chosen to capture the noise generated by the overall system-level response. This served as a means of validating the serviceability noise experienced by users/occupants. Sound pressure level measurements and an acoustic camera were used simultaneously to identify the noise sources. The creaking noise measurements were compared for different specimens of Assemblies 1 and 2 and the effects of different construction details (e.g. fixing method, plasterboard ceiling lining, etc.) on wind-induced creaking noises were discussed. The results of this study can provide valuable insights for manufacturers and designers to minimize creaking noises in drywall partition systems and propose new construction techniques to improve the serviceability of high-rise buildings.

Life cycle and efficiency assessment of fixed-bed bioreactor using recycled shredded plastics compared with conventional activated sludge bioreactor for dairy wastewater treatment

Adopting a highly efficient and low-cost bed bioreactor for the treatment of high-strength dairy wastewater has received unprecedented significance. Therefore, the concept of “waste as a resource” was brought up in this study and recycled shredded plastics (RSPs) were used to structure a fixed bed for activated sludge expansion. The performance of the RSP-attached growth system (AGS) and conventional suspended growth system (SGS) with intermittent anaerobic/aerobic conditions were scrutinized for dairy wastewater treatment. In addition, their environmental repercussions, greenhouse gas (GHG) emissions, and ecological footprint were explored to provide innovative insights into the field of research. The AGS system outperformed with substantial COD, nitrate, and phosphorus removal efficiencies (>89 %) in hydraulic retention time of 4 h, aeration time of 27 min, and COD/P ratio of 120. Notably, the SGS system outcompeted in the environmental impacts and energy usage, which accounted for 1.03–4.38 times higher than that for the AGS system. The electricity consumption and wastewater treatment process had striking roles in human carcinogenic toxicity, freshwater/marine ecotoxicity, and human health. The most required energy for AGS and SGS operations was supplied by fossil fuels, which increment GHG emissions from 4.31 to 8.77 kg CO2 eq for the AGS and SGS, respectively. Moreover, the reduction of electricity usage dramatically decreased human carcinogenic toxicity and marine ecotoxicity. Summing up, this study sheds light on the RSPs' capability to support activated sludge and ensure alignment with environmental criteria for dairy wastewater treatment.

Fate and partition of perfluoroalkyl acids (PFAAs) driven by particles in mangrove ecosystems: Mechanistic insights and environmental implications

A critical gap in understanding emerging pollutants in mangrove ecosystems should be addressed. Despite their ecological importance, the state of environmental quality in fragmented mangrove patches, especially emerging contaminants, remains largely uncharted. Our research presented an in-depth analysis of the distribution of perfluoroalkyl acids (PFAAs) across porewater, suspended particles, and sediment in these small, fragmented mangroves, revealing the mechanisms behind their distribution. The findings indicated that PFAA concentrations in sediments were generally lower than in suspended particles, except for C12–C14 perfluorinated carboxylic acids (PFCAs) and C4–C6 perfluorinated sulfonic acids (PFSAs). A comparison of contamination levels in different mangrove patches concurred with conventional water quality assessments and crab burrow surveys, showing that large artificially planted patches were less contaminated, while areas with intense human activity were more polluted. Notably, no significant differences were observed in the concentrations of long-chain PFAAs and PFCAs between patches (p > 0.1). Elevated crab burrowing activity and higher concentrations of perfluorobutanoic acid (PFBA) and perfluorohexane sulfonic acid (PFHxS) in suspended particles in low intertidal zones suggested that seafood, particularly crabs and shellfish, might be at risk of PFAA pollution. Rainfall-runoff was identified as the primary source of PFAA pollution in porewater and suspended particle systems in these areas. The transport of PFAAs and organic carbon in mangroves was influenced by the concentrations and properties of suspended particles. These insights were critical for developing targeted environmental management strategies to mitigate the impact of PFAAs and preserve the ecological integrity of mangrove ecosystems.

Sustainable concrete structures by optimising structural and concrete mix design

ABSTRACT Sustainable concrete construction can be achieved by combining optimised structural designs with low-carbon concrete (LCC). This paper demonstrates the importance of sustainable construction by analysing various design options for a typical suspended slab system in high-rise buildings. Pearson (2020) noted that concrete slabs make up approximately 47% of the embodied carbon (EC) in commercial and residential structures, with slabs alone comprising around 70% of the total concrete volume in residential buildings. This presents an opportunity to reduce EC through structural design choices. The analysis in this paper involved designing a post-tensioned (PT) flat slab system for a residential development in Sydney and then re-designing it as a reinforced concrete (RC) slab by adjusting slab thickness and reinforcement system. A key finding was that transitioning from an RC to a PT slab resulted in a 44% total EC reduction when using a 100% General Purpose Cement (GPC) blend. Further EC reductions can be achieved by implementing LCC. The chosen LCC blend for this study is 23% Fly Ash, 23% Ground Granulated Blast Furnace Slag, and 54% Cement (FA/GGBFS/GPC), demonstrating a 36% reduction in EC compared to a 100% GPC blend while maintaining acceptable workability, constructability, mechanical, and durability properties.

Life Cycle Assessment of Immobilised and Slurry Photocatalytic Systems for Removal of Natural Organic Matter in Water

This study investigates the environmental impacts caused by the scaling up of the photocatalytic purification of drinking water using ultraviolet light-emitting diode technology. The life cycle assessment methodology was utilised to estimate the environmental impacts of two different reactor setups commonly used in lab-scale studies: an immobilised and a suspended TiO2 catalytic system. The functional unit adopted was the treatment of 1 L of water with an initial 7.8 mg/L concentration of natural organic matter, achieving a final 1 mg/L concentration. The use of a suspended photocatalyst was found to have an environmental footprint that was 87% lower than that of the immobilised one. From the sensitivity analysis, the environmental hotspots of the treatment process were the electricity usage and immobilised catalyst production. Therefore, alternative scenarios investigating the use of a renewable electricity mix and recyclable materials were explored to enhance the environmental performance of the photocatalytic treatment process. Using a renewable electricity mix, a decrease of 55% and 15% for the suspended and immobilised catalyst, respectively, was observed. Additionally, the process of recycling the glass used to support the immobilised catalyst achieved a maximum reduction of 22% in the environmental impact from the original scenario, with 100 glass reuses appearing to provide diminishing returns on the environmental impact savings.

A Suspended, 3D Morphing Sensory System for Robots to Feel and Protect.

Artificial sensory systems with synergistic touch and pain perception hold substantial promise for environment interaction and human-robot communication. However, the realization of biological skin-like functional integration of sensors with sensitive touch and pain perception still remains a challenge. Here, a concept is proposed of suspended electronic skins enabling 3D deformation-mechanical contact interactions for achieving synergetic ultrasensitive touch and adjustable pain perception. The suspended sensory system can sensitively capture tiny touch stimuli as low as 0.02Pa and actively perceive pain response with reliable 5200 cycles via 3D deformation and mechanical contact mechanism, respectively. Based on the touch-pain effect, a visualized feedback demo with miniaturized sensor arrays on artificial fingers is rationally designed to give a pain perception mapping on sharp surfaces. Furthermore, the capability is shown of the suspended electronic skin serving as a safe human-robot communication interface from active and passive view through a feedback control system, demonstrating potential in bionic electronics and intelligent robotics.

An effective secondary suspension system for isolating the high-frequency vibrations of suspended monorail vehicle running on a flexible track beam

ABSTRACT Secondary suspension system is a core component of a suspended monorail vehicle (SMV), which plays a vital role in suppressing the car-body vibrations. This article aims to investigate the vibration isolation performance of an external secondary system (ESSS) for the SMV. Firstly, the structural features and mechanical mechanism of the ESSS are elaborated, which are compared with those of an existing internal secondary suspension system (ISSS) in the SMV. Then, an effective analysis method for the vehicle-track beam interaction of the suspended monorail system (SMS) is established based on the rigid-flexible coupling dynamics theory, in which the main modal information of the track beam is considered. Furtherly, applying the established analysis method, the vehicle-track beam vibrational responses between the ISSS and ESSS are compared under the local irregularity of beam-end junction and random track irregularity, and the superiorities of adopting the ESSS are revealed. Finally, by comprehensively considering the vehicle-track beam vibrational responses, several crucial parameters of the ESSS are selected appropriately. Results show that the ESSS has a significant advantage in isolating the high-frequency vibrations of the SMV compared with the existing used ISSS; simultaneously, it could also effectively decrease the track beam vibration. To guarantee good vehicle riding comfort, the vertical stiffness and damping with the ESSS are recommended to be 0.05∼0.2 MN/m and 10∼30 kN·s/m, respectively. Highlights ➢ Structural features and mechanical mechanisms of an effective ESSS for the SMV are introduced. ➢ A high-efficiency analysis method for vehicle-track beam interaction of the SMS is established. ➢ By a comparison with the commonly used IEEE, the advantages and significance of the ESSS are revealed ➢ Several crucial design parameters of the SMV with ESSS are selected appropriately.

The construction of a microalgal-bacterial biofilm reactor for enhanced swine wastewater treatment

Traditional biological wastewater treatment methods face challenges in treating swine wastewater with a low carbon-to‑nitrogen ratio. Microalgae show great potential in low-cost swine wastewater treatment for nutrient recovery. This study investigated the effects of altering the carbon/nitrogen/phosphorus (C:N:P) ratio in swine wastewater and immobilizing microalgae for enhancing treatment using Desmodesmus sp. A C:N:P proportion of 106:16:1 was determined to be optimal for treatment. The implementation of an inclined plate bioreactor facilitated microalgal adherence, forming a biofilm that improved treatment efficiency. The biofilm exhibited removal rates of 92 % for ammonia nitrogen (NH4+-N), 98 % for total phosphorus (TP), and 99 % for chemical oxygen demand (COD). The harvested biomass from the biofilm was 7.6 times higher than that from the suspended system with a high content (63 %) of fatty acids (C16:0, C18:0, C18:1n9c and C18:2n6c) suitable for biodiesel production. Proteobacteria were dominant in the biofilm, while Firmicutes and Bacteroidetes contributed to effective organic matter and nitrogen removal. These findings present a promising technology for cost-effective swine wastewater treatment and resource recovery.

A sensor-augmented pump with a predictive low-glucose suspend system could lead to an optimal time in target range during pregnancy in Japanese women with type 1 diabetes.

It is challenging for pregnant women with type 1 diabetes to maintain optimum glucose level to attain good neonatal outcomes. This study evaluated the efficacy of sensor-augmented insulin pump (SAP) with a predictive low-glucose suspend (PLGS) system in pregnant Japanese women with type 1 diabetes. SAP with PLGS was used in 11 of the 22 women with type 1 diabetes who delivered between 2011 and 2021 at the two medical institutions in Japan. Glucose management, insulin delivery suspension time (IST) and neonatal outcomes were retrospectively studied. In SAP with PLGS cases (n = 11), average glycated hemoglobin levels were < 6.5% throughout the pregnancy, and the time in range (TIR, 63-140mg/dl) was > 70% in the second and third trimesters. PLGS was safely used without inducing ketoacidosis. Positive correlation was observed between IST and TIR (r = 0.62, p < 0.01). Negative correlation was observed between IST and time below range (TBR) (r = - 0.40, p = 0.02), and IST and time above range (TAR) (r = - 0.45, p = 0.01). Total daily insulin dose was adequately increased without increasing hypoglycemia. There was only one heavy-for-date HFD) infant among the 11 newborns in SAP with PLGS cases. In cases without SAP (n = 11), target glycemic levels were difficult to achieve and there were 5 HFD infants among the 11 newborns. SAP with PLGS was safely and effectively used in pregnant women with type 1 diabetes to achieve target glucose levels without increasing the risk of hypoglycemia, which may have led to good neonatal outcomes. The online version contains supplementary material available at 10.1007/s13340-024-00716-7.

A Field Study of Individual, Energy-Efficient, and Human-Centered Indoor Electric Lighting: Its Impact on Comfort and Visual Performance in an Open-Plan Office Part 1

In this field study, we examined the impact of human-centered lighting on an open-plan office environment, involving the participation of sixty office workers. The objective was to investigate the effects of the Circadian Stimulus (CS) and Equivalent Melanopic Lux (EML) metrics. This study took place at Istanbul Technical University in Istanbul, Turkey. The office was equipped with single Correlated Color Temperature (CCT) light emitting diode (LED) sources, featuring two different light beam distributions: Direct Suspended Linear (L1) and Direct and Indirect Suspended Linear (L2). To minimize energy consumption, we proposed simulations for a suspended individual lighting system. The office workers were invited to complete visual cognitive performance tests, proofreading tasks, and the Karolinska Sleepiness Scale (KSS) test to measure alertness. Additionally, participants were asked to provide feedback on the comfort criteria associated with the designed human-centered lighting concept. The preliminary findings from part 1 of this field study shed light on the potential of office lighting modifications in enhancing energy efficiency and meeting the standards set by WELL v2 2023 Q4 and UL Design Guideline 24480 (2019). Part 2 of this study will further optimize the proposed lighting quality concept to determine the most suitable individual lighting solution for office workers.