Acrylic Sheet Research Articles

Sky Cultivation Using Remote and Solar Power Source

Abstract— How to grow more food in less space with less water is the main concept involved in this project work. The former who doesn’t have more land can adopt this system by which more land can be created to produce more food than existing land. Rolling type of sky container garden concept is presented here which can be exposed to the sun with water and fertilizer feeding accessibility.A mini module of giant wheel structure is constructed with 8 compartments for cultivating the crops, the idea of choosing this kind of mechanism is to grow more crops in less ground place/area. This rotary type of multi soil containers attached to the main structure of wheel mechanism operates on a simple wheel mechanism that can minimize the ground area or volume required for cultivating the food items like vegetables, grains, etc. The wheel mechanism is attached to the shaft of high torque DC motor at its centre point at certain height, now this motor is controlled through a remote control unit designed with RF modules and mini embedded systems. The control circuit built with 89C2051 chip & relays is designed to rotate the wheel either in clock wise or in anti-clock wise such that hanging containers attached to this mechanism can be positioned to the ground level accessible point for watering and other maintenance activities. Hanging containers filled with soil are constructed with acrylic sheets. Since it is a prototype module, the basic concept of 8 hanging type of small soil containers are used and are attached to the moving wheel for demo purpose. But for real time applications giant wheels can be constructed with less expenditure. The structure of mechanism occupies very less ground place such that the vacant place also can be used for cultivation. Solar energy is used to drive the wheel, for this purpose, 10W panel is used and its output is used to charge the battery such that in absence of Sun also the mechanism can be activated.

Mechanism for tension adjustment in tendon driven remote center-of-motion mechanism for minimally invasive surgery

Tendon drive is used for transmission design in applications ranging from wearable rehabilitation and surgical robots to industrial robots. For their efficient operation, one of the principal design requirements is to have adequate tension in the tendon element. This paper introduces a novel mechanism for tension adjustment using a secondary cable-pulley arrangement via a lever mechanism. An adjustment in a tension spring applies a force in the tendon element meant for the transmission of remote centre-of-motion (RCM) mechanism for medical robotic application. Thereafter, the current work presents the kinematic and force analyses of the proposed concept along with a series of plots of various mechanism parameters. The variation of these parameters is in good agreement with the physical motion of the devised mechanism. As compared to the conventional methods of tension adjustment, the proposed concept is a better solution for problems that arise due to low manufacturing tolerances and the need for independent tension adjustment in a multi degrees-of-freedom tendon driven RCM mechanism. In the preferred embodiment, it is proposed to use cables (wire-ropes) as tendon elements to drive a mechanically constrained double-parallelogram-based RCM mechanism which is extensively used for Minimally Invasive Surgery. From this implementation, it is learnt that the presented mechanism can be implemented in several configurations. However, this paper presents the preferred embodiment only which meets the demand, of invariant tendon length, of the RCM mechanism under consideration. An initial prototype is made from acrylic sheets, PLA material, and standard elements (like bearings, pulleys, aluminum pins, 0.5 mm stainless-steel wire-rope, etc.) using laser micromachining and 3D printing.

Testing and Performance Validation of Ordinary Evacuated Tube Based Parabolic Trough Collector for Low Enthalpy Process.

In this paper, a parabolic trough collector is designed and fabricated, and its thermal performance is evaluated for hot water generation. Theparabolic trough collector was built with a 90o rim angle with a small concentration ratio of 5.5, and the collector aperture area is1.7 m2.Both side open ordinaryevacuatedglass tube and acrylic sheet were usedas a receiver and reflective surface,respectively.Siemens NX has been used to simulate the maximum wind load of 1000 N. The thermal output of the collector is evaluated for close and open circuits as per ASHRAE 93 1986 (RA 91) standard. The achieved maximum efficiencies

Root-TRAPR: a modular plant growth device to visualize root development and monitor growth parameters, as applied to an elicitor response of Cannabis sativa

BackgroundPlant growth devices, for example, rhizoponics, rhizoboxes, and ecosystem fabrication (EcoFAB), have been developed to facilitate studies of plant root morphology and plant-microbe interactions in controlled laboratory settings. However, several of these designs are suitable only for studying small model plants such as Arabidopsis thaliana and Brachypodium distachyon and therefore require modification to be extended to larger plant species like crop plants. In addition, specific tools and technical skills needed for fabricating these devices may not be available to researchers. Hence, this study aimed to establish an alternative protocol to generate a larger, modular and reusable plant growth device based on different available resources.ResultsRoot-TRAPR (Root-Transparent, Reusable, Affordable three-dimensional Printed Rhizo-hydroponic) system was successfully developed. It consists of two main parts, an internal root growth chamber and an external structural frame. The internal root growth chamber comprises a polydimethylsiloxane (PDMS) gasket, microscope slide and acrylic sheet, while the external frame is printed from a three-dimensional (3D) printer and secured with nylon screws. To test the efficiency and applicability of the system, industrial hemp (Cannabis sativa) was grown with or without exposure to chitosan, a well-known plant elicitor used for stimulating plant defense. Plant root morphology was detected in the system, and plant tissues were easily collected and processed to examine plant biological responses. Upon chitosan treatment, chitinase and peroxidase activities increased in root tissues (1.7- and 2.3-fold, respectively) and exudates (7.2- and 21.6-fold, respectively). In addition, root to shoot ratio of phytohormone contents were increased in response to chitosan. Within 2 weeks of observation, hemp plants exhibited dwarf growth in the Root-TRAPR system, easing plant handling and allowing increased replication under limited growing space.ConclusionThe Root-TRAPR system facilitates the exploration of root morphology and root exudate of C. sativa under controlled conditions and at a smaller scale. The device is easy to fabricate and applicable for investigating plant responses toward elicitor challenge. In addition, this fabrication protocol is adaptable to study other plants and can be applied to investigate plant physiology in different biological contexts, such as plant responses against biotic and abiotic stresses.

The effect of surface tension on the color Doppler ultrasound twinkling artifact

Imaging crystalline structures with Doppler ultrasound can produce a rapid color shift, termed the twinkling artifact, that can assist in diagnosing pathological mineralizations such as kidney stones, heterotopic ossification, gout, and breast microcalcifications. Twinkling is theorized to arise from scattering off surface crevice microbubbles, which are affected by the surface tension between the bubble and surrounding medium. In this study, we evaluated the effect of surface tension on twinkling in pure crystals. Cholesterol, calcium phosphate, and uric acid crystals were grown in vitro (n = 5 each) and imaged with a Philips/ATL L7-4 transducer and Vantage-128 research ultrasound system. Crystals were imaged in water while varying surfactant concentration (0%–4%) leading to surface tensions that ranged from 45–72 mN/m. Surface tension of the solution was determined by measuring the contact angle of 0.1-mL droplet on an acrylic sheet exposed to air. As the concentration of surfactant increased, twinkling was found to decrease by ∼20% for cholesterol and calcium phosphate and ∼10% for uric acid. These results continue to support the crevice bubble theory of twinkling and suggest the importance of surface tension when evaluating minerals with the twinkling artifact. [Work supported by NSF-CAREER-1943937 and NSF-GRFP-DGE1255832.]

Evaluating impact of medium variation on dose calculated through planning system in a low cost in-house phantom

Purpose: In radiotherapy, accuracy in dose estimation of dose calculation methods is critical. The influence of deformity on radiation dose calculations derived by planning system is evaluated in present study. The goal of study was to create a low-cost inhomogeneous phantom for measuring absorbed dose using an Ionisation chamber and Gafchromic film, which was validated using treatment planning system (TPS) dose outcome. Methods:and Materials: The central axis dose calculations were computed using Pencil Beam Convolution algorithm (PBC), Collapsed Cone Convolution (CCC) and Monte Carlo (MC) algorithm in the Monaco treatment planning system using an In-house phantom (20 × 20 × 20cm3) made up of acrylic sheet containing water and inhomogeneous material wooden powder equivalent to lung. Phantom was scanned in Computed Tomography (CT) scanner and image set was sent to the planning workstation. The depth dose evaluations were performed using ionization chamber and Gafchromic film with same beam settings and monitor units in every setup. Following that, the calculated doses obtained from TPS and measured depth doses were compared. Results: The results was reported for photon energies 6MV, 10MV, 15MV, 6FFF and 10FFF at varying field sizes of 4 × 4 cm2, 5 × 5 cm2, 10 × 10 cm2, and 15 × 15 cm2. MC maximum dose variation predicted was 2.06% in 15MV of measured chamber dose and −2.06% of measured gafchromic film dose in 6MVFFF. CCC maximum dose variation predicted was 2.68% of measured chamber dose in 6MV and 3.31% of measured gafchromic film dose in 6MV whereas PB maximum dose variation predicted was −5.94% in 15MV of measured chamber dose and −11.6% of measured gafchromic film dose in 6MVFFF. Conclusion: Low-cost in-house phantoms can be utilised to assess point and planar doses during patient-specific quality assurance in centres that don’t have accessibility to phantoms due to the high cost of commercially available tools.

UV Disinfectant Médium

The objective was to design and create an airtight environment that disinfects objects and inactivates microorganisms with radiation, in addition to being easy to use and at a low cost. With a metallic structure, acrylic paint coatings, an acrylic sheet and a UV light lamp, which is controlled with a radiation sensor and another movement sensor. To be able to disinfect the interior of the box allowing to inactivate microorganisms at a low cost and easy handling. When using radiation as a disinfectant, microorganisms do not generate resistance and it is an easy- to-use method. The design was based on equipment used to disinfect, the design was carried out in design software, then an analysis of materials for its construction was carried out, taking into account radiation and other variables such as temperature. The results were the analysis of the correct function of the seals in the box, the power of the radiation to inactivate and the easy handling of the equipment.

The Do-It-Yourself (DIY) novel, safe and cost-effective ophthalmic cubicle (coronicle) in COVID-19 era

The coronicle (corona + cubicle) provides state-of-the-art features required for comprehensive ocular evaluation. Assembling this cubicle requires acrylic sheets, aluminum beading, fevicol, araldite paste, and a jigsaw cutting blade, which can be done in a do-it-yourself template. Dimensions of the cubicle are 16 × 16 × 8 feet with only a total area of 256 square feet; thus, restricting patient movement inside hospital premises. Social distancing norms with three feet distance between the machines were incorporated while installing the ophthalmic gadgets within the cubicle. The cubicle encompasses slit-lamps, auto refractometer, lensometer, fundus capture device, optical coherence tomography, optical biometry, manual keratometry, corneal topography, and noncontact tonometer. Customized openings in the cubicle were made in front of each device, for the patient's head and chin rest positioning during the examination, and can be closed with sliding doors during times of disuse. An acrylic groove was provided to accommodate the patient's feet. Coronicle has helped instil, both patient and medical personal safety during COVID-19 and has withstood the test of time since its inception in May 2020. In this manuscript, we have discussed the economics and validated the utility of the cubicle, in terms of the quantitative usage of ophthalmic gadgets present inside the cubicle versus outside the cubicle for the past 19 months, since the installation of the cubicle; along with the cubicle's additive highlights and its role after the pandemic is over.

Performance analysis of roof collector used in the solar updraft tower

The solar collector is the heart of the solar updraft tower as the solar updraft tower's performance depends on the generation of solar energy under the collector roof. Hence, the current research work's objective is to analyze the performance of various roof collector materials used in the solar updraft tower. An experimental set-up of a solar updraft tower was developed and installed in Nagpur, India, in the year 2018. Experimentation was carried out using different roof collector materials like glass, acrylic sheet, polycarbonate sheet and crystalline sheet at a chimney height of 4.8 m and 3.6 m. The results showed that by increasing the 33.33% height of the chimney from 3.6 m to 4.8 m, output power rises 37.92%, 36.13%, 16.78% and 32.18% for glass, acrylic, crystalline and polycarbonate sheet as the collector roof material respectively. The system's output power increases in the range of 5% to 15% with the glass as the roof collector material compared to the acrylic sheet, crystalline sheet, and polycarbonate sheet. The experimental values are compared with analytical values of the power developed, and these were found to be in good agreement, thus validating the experimentation.

White‐light visible light communications based on multiple photoluminescence of fluorescent acrylic sheets

A novel method that converts blue light into the white-light for illumination and provides the high-speed visible light communication link is introduced. Typical phosphors for creating white-light cause low bandwidths and restrictions on changing correlated colour temperatures. The proposed method deals with such issues by utilising combinations of photo-luminescence lights from cost-effective fluorescent acrylic sheets. Characteristics of the light generated from the proposed method show that white-lights with various correlated colour temperatures can be straightforwardly generated whilst providing orders of magnitude higher bandwidth than that from the conventional approaches using the phosphors. A high-speed white-light visible light communication demonstration based on a blue laser-diode and the fluorescent acrylic sheets is presented, showing the data-rate of 2.16 Gb/s with a bit-error-rate less than 3.8 × 10−3 by using an optical orthogonal frequency division multiplexing scheme.

Ecological light transmiting concrete made from glass waste and acrylic sheets

In this research, recycling of 100% glass waste was evaluated for the manufacture of self-compacting mortars for applications in translucent building systems. The glass waste (WG) was ground and used as a fine aggregate in mortar mixtures with cement:WG proportion of 1:1.5, 1:1,75 and 1:2.0 with different water/cement (W/C) ratios. Properties such as fluidity, compressive strength, density, porosity, absorption, thermal properties, and characterization of the microstructure by SEM were analyzed. The results showed that as the WG content increases from 1:1.5 to 1:2.0 the compressive strength of the mortar decreases a maximum of 2.8% in samples with W/C:0.47, and this is due to the formation of microcracks and porosities, which cause the formation of a weakened and sparse interfacial zone which could be identified in the SEM tests. Nevertheless, the compressive strengths were between 20.6 MPa − 32.07 MPa, water absorption for mortars was between 12,92–14,74% and porosities from 23.02% to 25.93%. The thermal conductivity of the mortars was between 0.64 and 0.71 W/m.K. Additionally, the results of the spectrophotometry test for light transmission and the simulation in MATLAB allowed to obtain the brightness in the samples, it was possible to observe that the brightness varies according to the shape of the openings of the blocks, being the A design which allowed a greater passage of light (16%), and the materials developed could be classified as green building materials.

An experimental method to correct low-frequency concentric artifacts in photon counting CT

Large-area photon counting detectors (PCDs) are usually built by tiling multiple semiconductor panels that often have slightly different spectral responses to input x-rays. As a result of this spectral inconsistency, experimental PCD-CT images of large, human-sized objects may show high-frequency ring artifacts and low-frequency band artifacts. Due to the much larger width of the bands compared with the rings, the concentric artifact problem in PCD-CT images of human-sized objects cannot be adequately addressed by conventional CT ring correction methods. This work presents an experimental method to correct the concentric artifacts in PCD-CT. The method is applicable to not only energy-discriminating PCDs with multiple bins but also PCDs with only a single threshold controller. Its principle is similar to the two-step beam hardening correction method, except that the proposed method uses pixel-specific polynomial functions to address the spectral inconsistency problem across the detector plane. The pixel-specific polynomial coefficients were experimentally calibrated using 15 acrylic sheets and 6 aluminum sheets of known thicknesses. The pixel-specific polynomial functions were used to convert the measured PCD-CT projection data to acrylic- and aluminum-equivalent thicknesses that are energy-independent. The proposed method was experimentally evaluated using a human cadaver head and multiple physical phantoms: two of them contain iodine and one phantom contains dual K-edge contrast materials (gadolinium and iodine). The results show that the proposed method can effectively remove the low-frequency concentric artifacts in PCD-CT images while reducing beam hardening artifacts. In contrast, the conventional CT ring correction algorithm did not adequately address the low-frequency band artifacts. Compared with the direct material decomposition-based correction method, the proposed method not only relaxes the requirement of multi-energy bins but also generates images with lower noise and fewer concentric artifacts.

Characterization of Non-linear Internal Waves Using PIV/PLIF Techniques

Internal waves are ubiquitous in the ocean. They often form in regions of high temperature or salinity variability as the pycnocline oscillates to form the wave (Phillips, 1966). They can be generated either from the interaction of tidal currents with submarine bathymetry (Garrett and Kunze, 2007) or by wind stress at the ocean surface (Munk and Wunsch, 1998). The current study addresses non-linear internal waves due to their importance in the mixing and dynamics of both atmospheric and oceanographic flows. Due to the significance of this phenomena, numerous investigations have been conducted to obtain satisfactory theoretical solutions for internal waves in several types of fluid systems. The verification of these models requires precise and accurate experimental data. It should be noted that such models generally assume simple two-layer stratified system separated by a sharp interface. In reality, there is a gradient of density at the interface of the two layers, which can make both experimental and theoretical analysis more challenging. To date, most experimental studies for several types of internal waves have been performed using ultrasonic probes, conductivity probes, resistance-type wave gauges, or salinity-sensor-type wave gauges, as given by Davis and Acrivos (1967),Koop and Butler (1981),Michallet and Barthelemy (1998) and Umeyama (2002). There is one recent study that used the particle image velocimetry (PIV) technique to determine the Eulerian velocity field of internal waves, but it lacks the detailed density measurements necessary to fully understand the flow (Umeyama and Matsuki, 2011). The current work aims to fully understand the dynamics of internal waves by measuring the density and velocity fields, and then comparing the experimental results with the theoretical non-linear wave solution. A laboratory-scale apparatus was created to replicate the flow characteristics of internal waves in a twolayer stratified system. An experimental configuration is presented with a density jump of 1.1 and 1.5 σt separately. Experiments are conducted in the tank (2.438 m × 50 cm × 50 cm), which was constructed from clear acrylic sheets with thickness of 1.905 cm. The schematic of the internal wavemaker apparatus is shown in Fig. 1(a) (Mohaghar et al., 2020). A line diffuser (PVC) was installed along the middle of the tank floor to be used to fill the tank. A half-cylinder plunger-type wavemaker was used to create a perturbation at the pycnocline represented by the interface between the density layers. On each revolution of the drive mechanism, the switch sent a voltage signal to the external trigger port of a pulse generator. By precisely controlling the delay following the external trigger signal, the pulse generator sent a signal to the Nd:YAG laser and the camera to capture an image at a targeted phase of the wave cycle. Images are recorded with a high resolution 29 MP CCD camera, (14-bits, 6600 × 4400 pixels). PIV was used to measure the velocity field, and the fluids in both layers were seeded with neutrallybuoyant particles. The seeded particles were illuminated using a dual-cavity New Wave Research Gemini PIV laser at wavelength of 532 nm, which is diverged into a sheet. Light entering the PIV camera passed through a 532 nm bandpass filter. The image pairs were processed with Insight 4GTM software using a 32 × 32 pixel final spot size with 50% overlap. A sample of PIV vector field for the case of ∆ρ = 1.5σt is shown in Fig. 1(b). In order to measure the density fields, the flow is visualized using the planar laser-induced fluorescence (PLIF) method for scalar visualization. A laser-fluorescing dye, Rhodamine 6G, is mixed into the heavier layer and the light sheet is used to fluoresce the dye. Following the procedures outlined by Mohaghar (2019), the dye concentration is then inferred from the digital images. In order to capture only fluorescence emitted by Rhodamine 6G, the camera is equipped with a notch filter blocking the 532 nm wavelength of light. A sample of a final processed PLIF image for the case of ∆ρ = 1.5σt is shown in Fig. 1(c). The interface location, density gradient, wave amplitude and period, velocity and vorticity fields, kinetic energy and shear strain rate are quantified by several phases in one wave cycle and subsequently compared with the corresponding predictions based on third-order Stokes internal-wave theory.

Trinseo will buy acrylic sheet firm Aristech Surfaces

Trinseo will buy acrylic sheet firm Aristech Surfaces

Levantamento de obras de arte em chapa acrílica em coleções Portuguesas

Acrylic sheet, also known by the commercial names Plexiglas or Perspex, consists of poly(methyl methacrylate) (PMMA). Attractive to artists since its development in the 1930s, it became especially popular during the 1960s. In Portugal, knowledge about its use by artists and its condition is scarce. In this work, the main Portuguese art collections were surveyed with the goal of gaining an overview of the use of acrylic sheet in the Portuguese art context and its current condition. The paper describes the methodology used and the results obtained regarding 137 artworks by 69 different artists registered as containing acrylic. Results show that this material is being used by Portuguese artists at least since the 1960s. It has been used in several artistic forms, from painting and sculpture to photography, installation, objects/reliefs, and artist books. Most of the artworks were in good or fair condition. The main problems observed were dust and dirt deposits, abrasion, and scratches.

Swimming against the Tide: Thoughts on Managing an Art Profession

Charles Gaines, Numbers and Faces: Multi-Racial/Ethnic Combinations Series 1: Face #7, Eduardo Soriano-Hewitt (Black/Filipino), 2020, acrylic paint, acrylic sheet, and photograph, 38 x 32 x 3½ in. ...

Impact of aerosol box on anxiety of the anaesthesiologist for intubation during COVID-19 pandemic: A single-blinded observational study.

Sir, Reports of healthcare workers (HCWs) getting infected during the coronavirus disease-19 pandemic are disturbing and tragic. The risk posed to HCWs especially anaesthesiologists during aerosol generating procedures (AGPs) is critical. Innovation of the aerosol box (AB) (made of acrylic or transparent polycarbonate sheet) may help to address this issue.[1] AB is a transparent plastic cube designed to cover a patient's head and has two circular ports through which the clinician's hands are passed to perform the airway procedure. It is a barrier device useful as an anti-splash or against direct cough from patient into the face of the proceduralist.[2] We conducted a survey from July 2020 to December 2020 to evaluate whether the AB really played a vital role in allaying anxiety of the anaesthesiologist regarding the risk of direct aerosol exposure or was it a hurdle in smooth working. The survey was distributed to experienced anaesthesiologists, who were routinely doing cases in general anaesthesia. After prior consent, we distributed the online survey to anaesthesiologists through their institutional emails, social media and WhatsApp messenger in our city. No data which could breech personal information was collected. They filled the questionnaire which enquired about their awareness, experiences, adventures and misadventures during induction and extubation with the AB [Table 1].Table 1: The questionnaireNinety anaesthesiologists responded to the survey questions. Only 29.60% of the participants had prior experience with the AB [Table 2]. Almost 70.40% of the study population was unaware of the use of this innovative barrier device. 46.30% participants came to know about AB from colleagues, whereas the rest came to know from social media and other sources. Thus, the results depicted that no first-hand experience or hands-on training for anaesthesiologists was present prior to using this box. 11.10% of the participants had an overall nice experience with use of AB while performing intubation and 85.20% felt that though it was helpful, it was a hurdle for intubation. 3.70% of the participants found it to be hazardous. Bag and mask ventilation was found to be easy by 14.80%, while 57.40% found bag and mask ventilation difficult with use of the box [Table 2]. Ease with endotracheal intubation was reported by 9.30%, while 83.30% of the participants faced difficulty. The majority (70.40%) of the participants agreed that AB prevented contamination with aerosol particles, whereas 13% disagreed about the efficacy. Use of AB made 68.50% of the participants mentally composed, while the rest were anxious. 7.40% of the participants felt that nothing can affect the composure of an anaesthesiologist. 55.60% of the respondents were more comfortable working with level 3 personal protective equipment (PPE) without AB. Almost 72.2% of the participants agreed to recommend AB to other colleagues for AGPs. During extubation, 37.0% of the participants were under-confident in use of the box, while 18.5% of the participants felt that it did not affect their psychology during extubation.Table 2: Summary of responses to all questionsOverall experience of the anaesthesiologists as per our survey was that the box acts as a hurdle for intubation and made bag and mask ventilation and intubation difficult. However, 70% of the study population felt that it prevented contamination with aerosol during AGPs, which was in compliance with the study conducted by Dalli et al.[3] This was in contrast to the study by Wakabayashi et al.,[4] who concluded that the effect of AB on endotracheal intubation difficulty is clinically irrelevant when an experienced anaesthesiologist intubates the trachea in normal airway conditions. The survey was inconclusive with regards to the confidence of the anaesthesiologist during extubation as per the meta-analysis by Sorbello et al.[5] The survey could also not conclude on the comfort with the use of the box as compared to level 3 PPE and was lacking in views on chances of accidental extubation and the box acting as an oxygen and virus reservoir.[6] We concluded from the survey that though the AB allays the anxiety of the anaesthesiologist, it acts as a hurdle for intubation during AGPs. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest. Acknowledgment The authors thank Dr Saifullah Tipu for his help in conducting the study.

Embryo Development and Behavior in Sea Urchin (Tripneustes gratilla) Under Different Light Emitting Diodes Condition

This study aims to evaluate the effect of light-emitting diodes (LEDs) of different wavelengths on the embryonic development, covering behavior, righting behavior, and phototaxis of collector urchins (Tripneustes gratilla). The collector urchins were divided into three groups according to the type of LED illumination they received: full-spectrum (400–750 nm wavelength), red light (630 nm), or blue light (450 nm). The results of the embryonic development experiment indicated that the blue LED group had the highest proportion of embryos reaching the prism stage at the 24th hour and the highest proportion of embryos entering the 4-arm pluteus stage, but it also had the highest death rate at the 48th hour. The full-spectrum and red LED groups exhibited similar speeds of embryonic development. In the experiment on covering behavior performed on adult urchins, our findings indicated that the blue LED group gripped the most acrylic sheets for cover, exhibiting the most covering behavior, followed by the full-spectrum group and then the red LED group. Moreover, behavior varied with coloration, as collector urchins with a lower level of melanin exhibited more covering behavior than those with a higher melanin level. In addition, the righting behavior experiments demonstrated that the blue LED group spent the longest time righting themselves. It is possible that the relatively strong stimulation from the blue LED illumination led to a higher level of stress in the collector urchins and hence slowed their righting. The phototaxis experiment revealed the most significant negative phototactic response in collector urchins when they were under the blue LED light, followed by the full-spectrum light; the red LED light did not induce any positive or negative phototactic response in the collector urchins. This experimental result verified collector urchins’ high sensitivity to and dislike of the blue LED light. The study results confirmed that the blue LED light environment accelerated the embryonic development of collector urchins; however, the relatively strong stimulation from that light also caused them to engage in covering behavior or move away from the light. These results indicate that short-wavelength irradiation significantly affects the embryonic development and behavior pattern of this species.

Smartphone-based technique for the determination of a titration equivalence point from an RGB linear-segment curve with an example application to miniaturized titration of sodium chloride injections

A smartphone-based technique for determining the titration equivalence point from a linear-segment curve was developed for the first time. In this method, a titrant in an increasing microliter-volume was added to a set of sample aliquots containing an indicator covering both sides of the equivalence point. The solutions were subsequently photographed in one shot, in a dark box using a smartphone camera and an illuminating screen of a tablet or light emitting diode lamps arranged below a white acrylic sheet as a light source. After the colors of the solutions were delineated to Red, Green, and Blue (RGB) values, 1/log G was used to construct a plot in which the equivalence point was located at the intersection of the two lines in the region before and after the equivalence point. The technique was successfully applied to the miniaturized titration of sodium chloride injections, showing the good linear relationship of equivalence points to the sodium chloride concentration in the range of 0.4163–0.9675% w/v (R2 of 0.9998). The assay was accurate (% recovery of 98.92–100.52), precise (% relative standard deviation ≤ 1.20), and unaffected by the use of different types of microplates, smartphones, and RGB analysis tools. Additionally, it required no expensive nor complicated equipment and offered the possibility of performing analysis on a single smartphone device when it was used with a mobile application developed to aid data processing and immediate production of reports of analytical results.

Reusable Capillary Flow-Based Wax Switch Valve for Centrifugal Microfluidics

Introduction: This paper presents a new repeatable Open-Close switch valve (SV) for the CD microfluidic platforms. The SV is designed by using a combination of controlled phase change and capillary flow of Ferrowax. The phase change of the wax is controlled using a laser. When the wax is illuminated with a laser, the energy of the laser is absorbed by the Ferro particles embedded inside the wax, causing the wax to melt. The melted wax can spontaneously wick through capillary channels due to its low contact angle. The Open-Close nature of the valve is attained by rationally designing the capillary flow path of the wax. The capillary flow path design is such a way that the melted wax is directed to the open fluidic path (Normally open configuration) to block the channel (Close configuration). The reversal of the blocking is achieved by remelting the wax and driving it to the overflow chamber downstream. A unique wax flow path is also designed to enhance the capillary flow and the response time of the valve. Background: Centrifugal platform-based CD fluidics has created a new paradigm of inexpensive point-of-care diagnostics[1]. It is now widely used in applications like polymerase chain reaction assays, blood plasma separation, etc.[2,3] Since CD fluidics has presented an innovation in point-of-care diagnostics, it is essential to have a proper valving system for reliable opening/closing of the channels. Currently, there are two main types of valves in the CD platform: laser valves and z-axis wax valves. Both of these valves are good for one-time use only and have complex fabrication routes. Therefore, there is a need for simple, reusable SV in CD fluidic platforms. Theory: The capillary pressure drives the capillary flow in a channel. The capillary pressure difference between atmosphere and the liquid meniscus inside a rectangular microchannel (Pc) is given by Young-Laplace’s equation:-Pc = 2γ(cosθ)(1/w+1/h) (1)where γ is the surface tension, θ is the contact angle with the channel material, w is the width of the channel, and h is the height of the channel. In this design, the resistance offered by the trailing liquid is given by the equation:Rhyd = 12μL/(h3w*(1-0.63(h/w)) (2)For capillary flow, the flow rate (Q) can be obtained byQ = wh(dL/dt) = -Pc/Rhyd (3)For a shallow channel (h<<w), we can neglect the terms containing 1/w, giving the following simplified equation for the flow velocitydL/dt = γ(cosθ)h/(6μL) (4)Upon integration, the fluid length at an instant t is obtainedL = √(γht(cosθ)/3μ) = W√t (5)where W is the Washburn’s constant. We use a new channel design and a flexible adhesive film, and the modified channel shows significant improvement in the capillary flow velocity. A modified empirical model capturing this effect is currently being developed. Materials and Method: The channels and the chambers are milled on an acrylic sheet of thickness 3 mm using Tormac PCNC CNC milling machine (Fig 1a). The Ferro-wax is prepared by mixing Sigma Aldrich Paraffin wax (MP 53 - 37oC) with Ferrofluid (Ferrotec EFHI 60 cc) at the ratio of 2:1 and stirring the mixture at 65oC for 12 hours. The mixture is brought down to room temperature and placed inside the designated chamber. Then, the CD is laminated using a single side pressure-sensitive adhesive (Fig 1a). To achieve Close configuration (Fig 1b), the wax inside the CD is heated up for 5 minutes at 65oC. The melted wax flows to the reagent flow path and solidifies to block the channel. Remelting the wax and directing the melted wax to the overflow chamber brings the valve back to the Open configuration (Fig 1b). The unique channel edges for enhanced capillary flow are fabricated by applying two layers of tape (Fig 1a). Experimental Results:- Experimental characterization of SV was performed by fabricating channels having cross-section areas ranging from 0.05 to 0.625 mm2. A 2.32 W laser placed at a distance of 3 mm from the top surface of the CD is used for heating the Ferrowax. The Normally Close configuration (Fig 1b) is achieved by heating the wax inlet chamber for 5 minutes at 65oC. The wax is driven to the reagent channel by moving along the edge gaps of the wax chamber. The solidified wax prevents the fluid from moving downstream. The sequential release of the reagent is achieved using SV as shown (Fig 1c, 5). A ‘teeth’ design is used at the bottom of the wax inlet to avoid bubble formation inside the chamber. This teeth design also ensures a large number of Open-Close operations for a given amount of wax. Finally, we demonstrate the fidelity of the SV closure (Close configuration) on the CD platform on upwards of 7000 RPM. A parametric study of the air gap is being carried out to determine an optimized design for a faster response.