Low-cost Model Research Articles

Performance enhancement of electrodialysis regeneration of deep eutectic solvent for liquid desiccant air conditioning systems

Despite the promising energy-saving potential of the electrodialysis regeneration technique for liquid desiccant regeneration in air conditioning systems, there are still issues that need to be resolved in electrodialysis separation systems, such as the high initial cost owing to the complexity of the cell gaps, over-limiting current, and electro-osmotic flow effects. This study utilized stereolithography (SLA) 3-D printing technology to manufacture a low-cost scalable model of an electrodialysis system. An electrodialysis system with a cell gap of 5 mm and serpentine flow feed spacers was investigated to regenerate deep eutectic solvent (DES) developed from choline chloride and ethylene glycol as a bio-friendly liquid desiccant for air conditioning systems. Ammonium chloride electrode rinsing solution with about 250 mS/cm electric conductivity was utilized to enhance the conductive properties of the system. The optimum parametric operating conditions for the system are found to be around 0.0058 m/s for the circulation flow rate, 0–4 wt.% for the concentration difference of the diluted and regenerated solutions' cells, and 6–8 V voltage supply energy input. In 60 minutes of operation, the current efficiency value of the constructed model was discovered to be as high as 65.82%. Matching the performance threshold of the commercial electrodialysis equipment described in the literature for regenerating lithium chloride conventional liquid desiccant.

Vanillic Acid Improves Stress Resistance and Substantially Extends Life Span in Caenorhabditis elegans.

Aging is the root cause of several pathologies like neurological and cardiovascular diseases. Identifying compounds that improve health span and extend life span, called geroprotectors, could be crucial to preventing or at least delaying the onset of age-related diseases. In this regard, the nematode Caenorhabditis elegans (C.elegans) is emerging as an easy, efficient, low-cost model system to screen natural products and identify novel geroprotectors. Phenolic acids can be found in a wide range of natural products that are part of the human diet. Vanillic acid (VA) is a phenolic acid that has previously been attributed with antioxidant, anti-inflammatory, and neuroprotective features. To determine whether these beneficial health effects amount to an extension of health span and life span, in this work, we thoroughly explore the effect of VA on C.elegans stress resistance and life span. We found that VA increases thermotolerance (19.4%), reduces protein aggregation (between 30% and 40%), improves motility, and extends life span by almost 50%, an extent hardly ever achieved with a natural compound. The increased thermotolerance induced by VA is independent of the insulin/insulin-like growth factor-1 signaling pathway but requires heat shock factor-1 and is associated with increased heat shock protein-4 (HSP-4) and hsp-16.2 expression. These results provide new insight into understanding the therapeutical properties of VA and warrant further investigation of VA as a novel geroprotector.

In search of sustainable strategies for low-cost long-haul airlines

This paper explores whether some guiding principles exist to make the low-cost long-haul airline model work (LCLH). Few airlines using the LCLH model have survived, raising questions about the transferability of the low-cost model to long-haul operations. The article contributes by bringing together strategic thinking and various characteristics of past LCLH attempts. The findings suggest that LCLH airlines should seek cost advantages through optimum stage lengths by employing a hub strategy; to facilitate self-connections of relevant customer segments by reducing passengers' perceived connection risk; to operate efficient single-type aircraft on underserved routes at fares that stimulate the “Southwest Effect”; and to optimize productivity through flexible operations. Achieving and maintaining a fragile cost model like LCLH requires innovation, clear trade-off decisions to sustain fit, managed growth, and a competent workforce that cements the high fit needed.

A low-cost prosthetic orbital simulation model for endoscopic anterior ethmoid artery ligation.

This study aimed to develop and evaluate a low-cost orbital prosthesis for simulation of endoscopically assisted intra-orbital anterior ethmoidal artery ligation. A low-cost orbital prosthesis was built and evaluated by ENT surgical trainees. Feedback was given following the assessment in the form of a face validity questionnaire. Results were scored on a Likert scale of 1-7 (low to high). Trainees had limited exposure to the procedure (40 per cent) and predominantly low levels of confidence (mean, 3.67) that correlated with a lack of first-hand experience. The anatomy and likeness to human tissue of the prosthesis were both ranked highly, with mean scores of 5.0 and 4.93, respectively. The results of this study support the idea that a simple anatomical prosthesis for the simulation of endoscopic anterior ethmoidal artery ligation can be created with potential value to otolaryngology surgical training. To the authors' knowledge, this is the first documentation of simulated surgical epistaxis management using an artificial anatomical model.

Context-Aware Surrogate Modeling for Balancing Approximation and Sampling Costs in Multifidelity Importance Sampling and Bayesian Inverse Problems

Multifidelity methods leverage low-cost surrogate models to speed up computations and make occasional recourse to expensive high-fidelity models to establish accuracy guarantees. Because surrogate and high-fidelity models are used together, poor predictions by surrogate models can be compensated with frequent recourse to high-fidelity models. Thus, there is a trade-off between investing computational resources to improve the accuracy of surrogate models versus simply making more frequent recourse to expensive high-fidelity models; however, this trade-off is ignored by traditional modeling methods that construct surrogate models that are meant to replace high-fidelity models rather than being used together with high-fidelity models. This work considers multifidelity importance sampling and theoretically and computationally trades off increasing the fidelity of surrogate models for constructing more accurate biasing densities and the numbers of samples that are required from the high-fidelity models to compensate poor biasing densities. Numerical examples demonstrate that such context-aware surrogate models for multifidelity importance sampling have lower fidelity than what typically is set as tolerance in traditional model reduction, leading to runtime speedups of up to one order of magnitude in the presented examples.

SimSpine: A Cost-Effective Spinal Endoscopy Training Prototype for Neurosurgical Residents Skills Training

To develop and compare the SimSpine (Indigenously developed, low-cost model) and EasyGo (Karl Storz, Germany) systems for simulation of endoscopic discectomy. 12 neurosurgery residents six PGY 1-4 or equivalent (junior) and PGY 5-6 or equivalent (senior) each were randomly allocated (1:1) to either EasyGo or SimSpine endoscopic visualization systems for endoscopic lumbar discectomy simulation on the same physical simulator. After the first excercise, they switched over to the other system and the exercise was repeated. Time taken to dock the system, time to reach annulus, time required for task completion, dural violation and volume of disc material removed were used for calculating objective efficiency score (Ef). Subjective scoring (NETS criteria)1 was performed by four blinded mentors based on recorded video at two separate occasions two weeks apart. Cumulative scoring (CS) was calculated based on Ef and NETS scores. Performance metrics were similar across the two platforms, irrespective of participant seniority (p>0.05). Time to reach disc space and discectomy time improved for both EasyGo (p=0.07 and p=0.03 respectively) and SimSpine (p=0.01 and p=0.04 respectively) between first and second exercises. Ef and CS were better (p=0.04 and p=0.03 respectively) when EasyGo was used as the first device compared to SimSpine. SimSpine is a cost-effective viable alternative to EasyGo endospine for endoscopic lumbar discectomy simulation-based training.

Autonomous flight insurance method of unmanned aerial vehicles Parot Mambo using semantic segmentation data

Autonomous navigation of unmanned aerial vehicles (UAVs) has become in the past decade an extremely attracting topic, also due to the increasing availability of affordable equipment and open-source control and processing software environments. This demand has also raised a strong interest in developing accessible experimental platforms to train engineering students in the rapidly evolving area of autonomous navigation. In this paper, we describe a platform based on low-cost off-the-shelf hardware that takes advantage of the Matlab/Simulink programming environment to tackle most of the problems related to UAV autonomous navigation. More specifically, the subject of this paper is the autonomous control of the flight of a small UAV, which must explore and patrol an indoor unknown environment. Objectives: to analyse the existing hardware platforms for autonomous flight indoors, choose a flight exploration scenario of unknown premises, to formalize the procedure for obtaining a model of knowledge for semantic classification of premises, to formalize obtaining distance to obstacles using data camera horizontally employment and building on its barrier map. Namely, we use the method of image segmentation based on the brightness threshold, a method of training the semantic segmentation network, and computer algorithms in probabilistic robotics for mobile robots. We consider both the case of navigation guided by structural visual information placed in the environment, e.g., contrast markers for flight (such as path marked by a red tape), and the case of navigation based on unstructured information such as recognizable objects or human gestures. Basing on preliminary tests, the most suitable method for autonomous in-door navigation is by using\ object classification and segmentation, so that the UAV gradually analyses the surrounding objects in the room and makes decisions on path planning. The result of our investigation is a method that is suitable to allow the autonomous flight of a UAV with a frontal video camera. Conclusions. The scientific novelty of the obtained results is as follows: we have improved the method of autonomous flight of small UAVs by using the semantic network model and determining the purpose of flight only at a given altitude to minimize the computational costs of limited autopilot capabilities for low-cost small UAV models. The results of our study can be further extended by means of a campaign of experiments in different environments.

Effectiveness of a novel low-cost pelvic organ prolapse quantification system simulation model

Effectiveness of a novel low-cost pelvic organ prolapse quantification system simulation model

THE CONSTRUCTION METHOD AND EXPRESSION OF EXTERIOR/INTERIOR FINISHES IN THE WOODEN HOUSES DESIGNED BY TSUCHIURA KAMEKI BEFORE WWII

This paper analyzes the construction method and expression of exterior and interior finishes in the houses designed by Tsuchiura Kameki before WWII. Tsuchiura proposed a wooden dry construction system in the 1930s as a low-cost modern urban housing model and applied new materials such as slate board and fiberboard. In many houses, Tsuchiura painted the exterior white to make the joints unobtrusive impression and painted the interior in pale colors to soften the walls as the background of living space. Such exterior and interior presence are unique compared to other architect's dry construction houses.

Evaluation of an Equine Nasogastric Intubation Model for Training Veterinary Students.

Simulation in veterinary education is an important means of providing a safe, welfare-friendly way for students to hone their skills prior to performing procedures on live animals. Students may not get many chances to practice passing a nasogastric tube and checking for reflux in live horses during clinical rotations and extra-mural studies. A low-cost equine nasogastric intubation model was created at the University of Surrey, allowing students to practice passing a tube and checking for reflux. Thirty-two equine veterinarians evaluated the model for realism, and its potential usefulness in teaching. Veterinarians found the model to be realistic, supported its use as a teaching aid, and provided helpful feedback for possible improvements. In addition, 83 year 4 veterinary students rated their level of confidence before and after using the model for nine specific aspects of nasogastric intubation. Students showed significantly increased confidence levels in all nine aspects after using the model, and reported that they appreciated being able to practice the skill in a safe environment prior to performing it on a live horse. The results of this study suggest that both clinicians and students considered that this model has educational value, which supports its use for training veterinary students prior to clinical placements. The model provides an affordable, robust educational aid that can be used in clinical skills teaching, increases student confidence, and allows students to practice the skill repeatedly.

Patient-Specific 3D-Printed Low-Cost Models in Medical Education and Clinical Practice.

3D printing has been increasingly used for medical applications with studies reporting its value, ranging from medical education to pre-surgical planning and simulation, assisting doctor-patient communication or communication with clinicians, and the development of optimal computed tomography (CT) imaging protocols. This article presents our experience of utilising a 3D-printing facility to print a range of patient-specific low-cost models for medical applications. These models include personalized models in cardiovascular disease (from congenital heart disease to aortic aneurysm, aortic dissection and coronary artery disease) and tumours (lung cancer, pancreatic cancer and biliary disease) based on CT data. Furthermore, we designed and developed novel 3D-printed models, including a 3D-printed breast model for the simulation of breast cancer magnetic resonance imaging (MRI), and calcified coronary plaques for the simulation of extensive calcifications in the coronary arteries. Most of these 3D-printed models were scanned with CT (except for the breast model which was scanned using MRI) for investigation of their educational and clinical value, with promising results achieved. The models were confirmed to be highly accurate in replicating both anatomy and pathology in different body regions with affordable costs. Our experience of producing low-cost and affordable 3D-printed models highlights the feasibility of utilizing 3D-printing technology in medical education and clinical practice.

Making Headway in Surgical Education at Home and Abroad: Use of an Inexpensive Three-Dimensional Learning Model to Improve Plastic Surgery Resident Confidence in Mohs Defect Assessment and Closure Planning.

The development of simulation, particularly low-cost models, has become a focus of interest within plastic surgery education. Current simulators for Mohs reconstruction are either expensive or not reusable. The authors hypothesize that using a Styrofoam head model during an interactive teaching session will positively affect plastic surgery trainee comfort in designing Mohs reconstructive options. A cohort of integrated plastic surgery residents at a single institution performed a preactivity questionnaire to obtain baseline comfort in defect assessment and design for five Mohs defects. They subsequently underwent an interactive learning session and were instructed to design flaps on life-size Styrofoam heads with feedback from the senior author (M.L.B.). A postactivity questionnaire was completed to assess improvement in comfort in defect assessment and flap design. Three attending surgeons then compared trainee designs with the senior author's design to assess accuracy. All surveys were based on a five-point Likert scale. When analyzing all defects, average postactivity scores increased by 0.63 (SD, ±0.24) ( P = 0.008). Junior residents ( n = 8) had a greater increase in average score responses [mean, 1.07 (0.5 to 1.75)] compared with senior residents ( n = 9) [mean, 0.27 (0 to 1)] ( P < 0.001). When assessed by senior-level surgeons, senior residents had significantly greater accuracy in design for each defect ( P < 0.05) except cheek advancement flap ( P = 0.08). Participation in an interactive educational activity using a Styrofoam head model demonstrated significant improvements in trainee assessment and design of reconstructive options for Mohs defects.

Size-Resolved Field Performance of Low-Cost Sensors for Particulate Matter Air Pollution.

Particulate matter (PM) air pollution is a major health hazard. The health effects of PM are closely linked to particle size, which governs its deposition in (and penetration through) the respiratory tract. In recent years, low-cost sensors that report particle concentrations for multiple-sized fractions (PM1.0, PM2.5, PM10) have proliferated in everyday use and scientific research. However, knowledge of how well these sensors perform across the full range of reported particle size fractions is limited. Unfortunately, erroneous particle size data can lead to spurious conclusions about exposure, misguided interventions, and ineffectual policy decisions. We assessed the linearity, bias, and precision of three low-cost sensor models, as a function of PM size fraction, in an urban setting. Contrary to manufacturers' claims, sensors are only accurate for the smallest size fraction (PM1). The PM1.0-2.5 and PM2.5-10 size fractions had large bias, noise, and uncertainty. These results demonstrate that low-cost aerosol sensors (1) cannot discriminate particle size accurately and (2) only report linear and precise measures of aerosol concentration in the accumulation mode size range (i.e., between 0.1 and 1 μm). We recommend that crowdsourced air quality monitoring networks stop reporting coarse (PM2.5-10) mode and PM10 mass concentrations from these sensors.

Surrogate Aerodynamic Wing Modeling Based on a Multilayer Perceptron

The aircraft conceptual design step requires a substantial number of aerodynamic configuration evaluations. Since the wing is the main aircraft lifting element, the focus is on solving direct and reverse design problems. The former could be solved using a low-cost computational model, but the latter is unlikely, even for these models. Surrogate modeling is a technique for simplifying complex models that reduces computational time. In this work, a surrogate aerodynamic model, based on the implementation of a multilayer perceptron (MLP), is presented. The input data consist of geometrical characteristics of the wing and airfoil and flight conditions. Some of the MLP hyperparameters are defined using evolutionary algorithms, learning curves, and cross-validation methods. The MLP predicts the aerodynamic coefficients (drag, lift, and pitching moment) with high agreement with the substituted aerodynamic model. The MLP can predict the aerodynamic characteristics of compressible flow up to 0.6 M. The developed MLP has achieved up to almost 800 times faster in computing time than the model on which it was trained. The application of the developed MLP will enable the rapid study of the effects of changes in various parameters and flight conditions on flight performance, related to the design and modernization of new vehicles.

A real-time digital twin approach on three-phase power converters applied to condition monitoring

This paper describes a methodology based on the digital-twin concept applied to the condition monitoring of three-phase power electronics converters. The proposed solution does not need additional hardware circuits or sensor calibration. The digital replica acts as a permanent watchdog, working in parallel with the converter control system and providing in real-time the signals to be monitored. An application for a Three Leg Neutral Point Clamped (3L-NPC) converter is demonstrated including theoretical analysis for the digital model, practical considerations about the real-time execution of the virtual representation, and experimental verification. The combination of two optimization algorithms (Particle Swarm Optimization (PSO) and a genetic algorithm (GA)) working in series is employed to estimate the circuit parameters of interest, specifically the degradation of the output LC filter. The results shown in this paper serve as a first step for attaining a low-cost and robust parallel digital-twin model as a basis for its application to the concepts of monitoring and reliability.

Physical Analysis of a Waterproof Temperature Sensor Responsiveness for Agricultural Applications

This work analysis the responsiveness, accuracy and precision of a low-cost waterproof temperature sensor model DS18B20 and shows that simple procedures can allow these parameters analysis for other common temperature sensors. The water temperature is a parameter highly relevant for agriculture and aquaculture, and besides it has scientific, social and economic aspects that justify the present work, whose results are presented with quantitative parameters and justified according to solid measurement theories. This sensor has a digital design and requires only a very simple hardware to allow its connection to processors and, besides, it presented a very good accuracy and precision in the work tests.

Comparative validity of three simulation platforms for objective assessment of otoscopy skills.

To assess the face, construct and content validity of three different platforms for otoscopy skills assessment, using a traditional otoscope with manikin, digital otoscope (Tympahealth) with manikin, and traditional otoscope with a low-cost model ear (SimEar). Prospective mixed methods study. Tertiary hospital. Postgraduate trainees and expert assessors. Face and Content validity based on expert assessor ranking on each model and their feedback from semi-structured interviews. Construct validity based on Objective Structured Clinical Examination scores. Each platform differed in face, construct and content validity scores, with no one platform consistently outperforming others. Three main themes were identified during thematic analysis of expert assessor interviews: ability to assess what is seen, anatomical reality, and ease of use. The low-cost model showed greatest potential, where modification to include a silicone ear could lead to high validity with marginal increase in cost. Several modalities for assessing otoscopy skills exist, each with advantages and disadvantages. Modifications to a low-cost model, for use with either a traditional or digital otoscope, could prove to be the best model.

Ultra-wideband integrated photonic devices on silicon platform: from visible to mid-IR

Abstract Silicon photonics has gained great success mainly due to the promise of realizing compact devices in high volume through the low-cost foundry model. It is burgeoning from laboratory research into commercial production endeavors such as datacom and telecom. However, it is unsuitable for some emerging applications which require coverage across the visible or mid infrared (mid-IR) wavelength bands. It is desirable to introduce other wideband materials through heterogeneous integration, while keeping the integration compatible with wafer-scale fabrication processes on silicon substrates. We discuss the properties of silicon-family materials including silicon, silicon nitride, and silica, and other non-group IV materials such as metal oxide, tantalum pentoxide, lithium niobate, aluminum nitride, gallium nitride, barium titanate, piezoelectric lead zirconate titanate, and 2D materials. Typical examples of devices using these materials on silicon platform are provided. We then introduce a general fabrication method and low-loss process treatment for photonic devices on the silicon platform. From an applications viewpoint, we focus on three new areas requiring integration: sensing, optical comb generation, and quantum information processing. Finally, we conclude with perspectives on how new materials and integration methods can address previously unattainable wavelength bands while maintaining the advantages of silicon, thus showing great potential for future widespread applications.

Investigating a Workflow for Obtaining Physical Models from Digital Twins Obtained through Photogrammetry and TLS: New Ways for a Sustainable Dissemination of Heritage

The objective of this article is to generate and validate a workflow that allows us to print physical twins (models) from digital twins obtained from unique buildings of our architectural heritage. These physical twins will guarantee the preservation and diffusion of the cultural asset, and will promote new pedagogical ways to spread the heritage. In addition, these physical cufflinks are an interesting tool to guarantee universal accessibility through low-cost and rapid distribution typological models. We can overcome physical barriers and reach many more users, regardless of their economic, physical, or location conditions. To obtain this workflow, digital twins of architectural elements of high cultural value obtained by photogrammetry or terrestrial laser scanner will be used. The digital twin will be optimized through different platforms, and an optimized exchange file will be generated for its dissemination and printing. A digital platform will be proposed that guarantees the free distribution of these digital twins to any user. Finally, the physical twins will be obtained. For the development of this work, we have chosen to use 3D resin printers with SLA technology (selective laser exposure to light by laser) due to their performance and high quality in the models obtained.

Toxicity and behavioural effects of ocfentanil and 2-furanylfentanyl in zebrafish larvae and mice

The introduction of the so-called New Psychoactive Substances represents a problem of global concern due to several factors, including multiplicity of structures, poorly known activity, short half-life in the market, lack of pure standards etc. Among these problems, of the highest relevance is also the lack of information about metabolism and adverse effects, which must be faced using simple and low-cost animal models. On these grounds, the present work has been carried out on 5 days post fertilization zebrafish (Danio rerio) larvae in comparison with adult mice (Mus musculus). Ocfentanil and 2-furanylfentanyl were administered at different concentrations to zebrafish larvae (1, 10 µM) and mice (0.1, 1, 6, 15 mg/kg). The behavioural assay showed a decrease in basal locomotor activity in zebrafish, whereas in mice this effect was evident only after the mechanical stimulus. Larva extracts and mice urine were analysed by using liquid chromatography coupled to high resolution mass spectrometry to identify the metabolic pathways of the fentanyl analogs. For 2-furanylfentanyl, the most common biotransformations observed were hydroxylation, hydration and oxidation in zebrafish larvae, whereas mice produced mainly the dihydrodiol metabolite. Hydroxylation was the major route of metabolism for ocfentanil in zebrafish larvae, while in mice the O-demethylated derivative was the main metabolite. In addition, a study was conducted to evaluate morphological effects of the two drugs on zebrafish larvae. Malformations were noticeable only at the highest concentration of 2-furanylfentanyl, whereas no significant damage was observed with ocfentanil. In conclusion, the two animal models show similarities in behavioral response and in metabolism, considering the different biological investigated.