Inexpensive Apparatus Research Articles

Unchained Catenaries

Summary Catenaries are the curves formed by a uniform chain or cable suspended from two ends. They are seen in the natural world in structures such as spider webs, and they also occur in engineered structures, including bridges and overhead power lines. Catenaries and catenary arches are also employed in architecture for their beauty and strength. In this article, we look at catenaries where a chain is fixed at one endpoint but free to move over the other. Such catenaries will either be supported by the weight of the tail end of the chain and hence be “stable,” or else unwind off the free end and adopt the configuration of a vertically hanging chain. We develop two models, which are analyzed to determine the conditions under which a particular system will be either stable or unstable and determine the widest span for which a stable catenary exists. The predictions made here may be explored experimentally with relatively inexpensive apparatus. The models presented also invite extensions, such as more general free point locations and the addition of friction, which could dissipate the system energy.

Development of a multipurpose heat treatment apparatus favorable for the growth of solution-based large-size crystal

An inexpensive temperature-controlled apparatus has been developed with the intention to use it during the growth of any solution-based crystal. It consists of a metallic cell and an application-specific, stand-alone, and programmable electronic controller. That can purposely deliver unequal heating power independently to its three individual heating channels. The system was designed with the aid of an Arduino-Uno board. It was indigenously built within the laboratory with limited in-campus facilities and using locally available standard electronic modules and components. It may have diverse applications for controllable synthesis processes in scientific laboratories and its structural as well as electronic design can be modified easily according to any specific user requirement.

Electropolishing of Aluminum at Room Temperature Using a Green DES of Choline Chloride and Propylene Glycol.

For applications of aluminum where the smoothness or reflectivity of the aluminum matters, electropolishing is necessary to polish the aluminum surface sufficiently. This electropolishing is traditionally done with hazardous solutions in non-ideal conditions, such as low-temperature perchloric acid-ethanol mixtures. Here, we describe electropolishing of aluminum using a deep eutectic system composed of propylene glycol and choline chloride, with polishing accomplished at room temperature and using an inexpensive apparatus. This polishing was performed using both 99.5 and 99.99% pure aluminum, and scanning electron microscopy images show substantial improvement with both purities of aluminum. In addition, reflectivity measurements show significant improvement over sanding of aluminum. This method provides a simple, green method for electropolishing aluminum that can be used in any research where careful polishing of aluminum is necessary.

Exploiting microdistillation and smartphone-based digital-image colorimetry for determination of protein in foods

Because of their nutritional importance and industrial interest, determination of proteins is usual in food quality control. The Kjeldahl method, the most usual for protein determination and a reference to other indirect methods, is time-consuming and generates significant amounts of waste. Aiming to circumvent these drawbacks, this work proposes a simple, cost-effective, and more environmental friendly procedure based on microdistillation of the ammonium from Kjeldahl digests, absorption on an acid-base indicator solution, and digital-image colorimetry for protein determination in food. Microdistillation was carried out in a simple and inexpensive lab-made apparatus. The digital images were acquired by a smartphone camera under controlled illumination and the intensity of the reflected radiation was converted to the RGB color system using a free app (PhotoMetrix®). Measurements were based on the color change of phenol red from yellow to pink and the G channel (corresponding to the complementary color of the dissociated indicator) was taken as analytical response. A linear response was achieved within 5.0–50.0 mg/L ammonium, equivalent to 0.003–0.03 % protein (r = 0.996), as confirmed by the lack-of-fit test at the 95 % confidence level. Coefficient of variation (n = 10) and limit of detection (99.7 % confidence level) were estimated at 2.3 % and 2 mg kg−1 protein, respectively. A sample throughput of 12 h−1 was achieved with simultaneous sample processing. Protein amounts determined in foods of animal (milk) and vegetal (beans and lentils) origin yielded results in agreement with the micro-Kjeldahl reference procedure at the 95 % confidence level.

Polymer-Based 3-D Printed 140 to 220 GHz Metal Waveguide Thru Lines, Twist and Filters

This paper demonstrates the current state-of-the-art in low-cost, low loss ruggedized polymer-based 3-D printed G-band (140 to 220 GHz) metal-pipe rectangular waveguide (MPRWG) components. From a unique and exhaustive up-to-date literature review, the main limitations for G-band split-block MPRWGs are identified as electromagnetic (EM) radiation leakage, assembly part alignment and manufacturing accuracy. To mitigate against leakage and misalignment, we investigate a ‘trough-and-lid’ split-block solution. This approach is successfully employed in proof-of-concept thru lines, and in the first polymer-based 3-D printed 90° twist and symmetrical diaphragm inductive iris-coupled bandpass filters (BPFs) operating above 110 GHz. An inexpensive desktop masked stereolithography apparatus 3-D printer and a commercial copper electroplating service are used. Surface roughness losses are calculated and applied to EM (re-)simulations, using two modifications of the Hemispherical model. The 7.4 mm thru line exhibits a measured average dissipative attenuation of only 12.7 dB/m, with rectangular-to-trapezoidal cross-sectional distortion being the main contributor to loss. The 90° twist exhibits commensurate measured performance to its commercial counterpart, despite the much lower manufacturing costs. A detailed time-domain reflectometry analysis of flange quality for the thru lines and 90° twists has also been included. Finally, a new systematic iris corner rounding compensation technique, to correct passband frequency down-shifting is applied to two BPFs. Here, the 175 GHz exemplar exhibits only 0.5% center frequency up-shifting. The trough-and-lid assembly is now a viable solution for new upper-mm-wave MPRWG components. With this technology becoming less expensive and more accurate, higher frequencies and/or more demanding specifications can be implemented.

Experimental investigation on rock thermal properties under the influence of temperature

The rock thermal parameters is of basic interest in geophysical, underground and engineering applications. The most relevant properties are thermal conductivity, specific heat capacity and thermal diffusivity. The present paper focuses on thermal properties of several rock types and minerals under the influence of temperature. On one hand, we provide a detailed review of rock thermal parameters and available correlations, and on the other hand, a series of laboratory measurements are presented and data are analyzed. For specific heat capacity measurements at atmospheric pressure and over a temperature range from 20 to 600 °C, the Differential Scanning Calorimetry (DSC) method is used and an indirect method is proposed. The results demonstrated an increase of specific heat capacity with a second order polynomial regression. The thermal conductivity and thermal diffusivity were investigated between 20 and 180 °C using the Hot Disk method. A logarithmic decrease with temperature was observed. In addition, a simple and inexpensive apparatus for measuring thermal conductivity at room temperature (20.0 ± 0.2 °C) is described and the results are compared with the commercial device. The results showed good performance with the estimated errors below 10%. To improve the applicability of the obtained results, empirical equations are developed to predict the thermal properties as a function of temperature and other physical properties. It was observed that the empirical relationships and the predicted values by the proposed equations are in agreement with the experimental data and with literature. Research results in this paper can be used as a support for rock engineering and a solution of a range of scientific and applied problems.

A New Optokinetic Testing Method to Measure Rat Vision.

Optokinetic nystagmus (OKN) is a reflexive eye movement initiated by the motion of visual stimuli in the field of vision. The head-tracking movement associated with OKN is commonly used as a measure of visual function in rodents. To record OKN responses in normal and experimental rats, a simple and inexpensive apparatus has been developed. This setup uses two tablet screens to display the OKN visual stimulus consisting of high contrast black and white stripes generated using the OKN Stripes Visualization Web Application, a freely available software. The rat is placed inside a clear Plexiglass holder that limitsmovement so that therat's head continuously faces the OKN display screen. The position of the rat holder can be changed to adjust the distance between the rat and the display screen. A micro-camera positioned above the rat holder is used to record the rat's visual activities. These recordings can be used for quantitative assessments. Based on the presence or absence of clear head-tracking, the OKN responses at different spatial frequencies can be determined. The collected data demonstrates a novel technique for reliable measurement of visual acuity in normal and retinal degenerate rats.

Augmenting a single-point laser Doppler vibrometer to perform scanning measurements

Laser Doppler vibrometers (LDV) are used for non-contact vibration measurements of various structures and are frequently used for stringed instrument measurements. Single-point LDVs can be used with the roving hammer or LDV method for mode shape measurements, but this is time-consuming and requires constant attention. Scanning LDVs exist but are expensive and often out of reach of musical acoustics researchers. An inexpensive apparatus to modify a common single-point LDV such that it can perform automated scanning measurements is presented. The augmentation consists of a mirror galvanometer, impact hammer controller, and 3D printed mounting hardware. The scanning system is controlled by a microprocessor and can be easily automated. The total cost of the system, excluding the LDV and impact hammer, is under two hundred dollars. Measurements of guitars are presented to validate the scanning system and discuss any shortcomings.

A low-effort and inexpensive methodology to determine beam separation distance of multi-foci FLDI

A new method is presented to measure the separation distance between probing volumes of closely spaced multi-foci Focused Laser Differential Interferometers (FLDI). The accuracy and precision of this distance measurement directly translate into the quality of convection velocity measurements performed by means of arrays of FLDI. The suggested method is based on the detection of a propagating weak blast wave, generated with a simple and inexpensive apparatus using an automotive spark plug. Demonstration is conducted using an FLDI with two foci (D-FLDI). The generated blast wave is probed at multiple distances from its source to verify its weakening into an acoustic pulse, which offers ideal conditions to the proposed methodology. D-FLDI separation distance measurement using the new approach is compared to measurements using beam profiler images and to the alternative currently established in the literature, based on the FLDI response to a moving weak lens. Tests are made on varying internal configurations of the D-FLDI, while the distance between the two systems is kept constant. Results show the present method to have improved accuracy and robustness in comparison with the moving lens approach, while requiring significantly less effort. Measured separation distances obtained from blast wave detections in a single location are within 0.5 % of the reference value measured through the beam profiler. This procedure is therefore a practical and reliable alternative to the measurement using beam profiler imaging, with similar quality. Its advantages concern associated costs, flexibility when measuring in constrained spaces such as in proximity to walls, and applicability to systems in which beam imaging is not an option, such as multi-point line FLDI.

A New Method Based on LAMP-CRISPR-Cas12a-Lateral Flow Immunochromatographic Strip for Detection.

IntroductionCarbapenemase-mediated antimicrobial resistance is currently a hot spot of global concern. Carbapenem-resistant organisms are highly prevalent in hospitals associated with difficult-to-treat infections, resulting in poor clinical outcome due to limited treatment options. It is urgently needed to have a rapid, efficient, and convenient molecular assay for identifying such resistant strains.MethodsFor this end, we developed a new laboratory assay targeting Klebsiella pneumoniae carbapenemase (KPC) and New Delhi metallo-β-lactamase (NDM) based on loop-mediated isothermal amplification, CRISPR–Cas12a, and lateral flow immunochromatographic strip (CRISPR–Cas-LAMP-lateral flow strip). The method was designed to use a guide RNA (gRNA) to recognize the target DNA and guide Cas12a to cleave the target DNA, and simultaneously cleave any single-stranded DNA within the cleavage reaction system.ResultsThe cleavage products are visible to the naked eye on the lateral flow strip. This method is highly sensitive in direct detection of bacteria in samples containing at least 3×105 CFU/mL without the need for bacterial culture.DiscussionIt provides shorter turnaround time and higher specificity than the conventional bacterial culture and susceptibility testing method. This new assay is applicable for extensive use in hospital infection control, as well as identification and treatment of resistant strains due to simple operation and inexpensive apparatuses.

An Inexpensive Apparatus to Study Conservation of Angular Momentum in the Introductory Laboratory

While the three laws of conservation of energy, momentum, and angular momentum are all mentioned in introductory textbooks, there are few experiments through which students can investigate the conservation of angular momentum. Most experiments consist of collisions between rotating disks, in which one disk is dropped on another, or in which the rotational inertia of a single object is changed and the resulting change in angular velocity measured. This paper presents a method for studying collisions that centers on the conservation of angular momentum, and of rotational energy.

A simple laboratory flash apparatus for thermal diffusivity measurement: Modeling and application for composite material based on clay and straw

In this work. we have developed and tested a flash apparatus for thermal diffusivity measurement of building materials. After the test on homogeneous materials, this very inexpensive apparatus was then used to estimate the thermal diffusivity of some local materials based on clay and straw. To estimate this quantity, the measured temperature rise at the rear face of the sample was processed by solving analytically the transient heat equation based on a one-dimensional model with time-dependent convective boundary conditions. The obtained mathematical model takes into account the temporal shape f(t) of the heat pulse used to excite the front sides of the samples as well as four unknown parameters ie: the thermal diffusivity, the two Biots numbers related to the heat losses on the rear and the front sides and the maximum adiabatic temperature. For this purpose, the excitation form performed via a flashlight was experimentally measured and f(t) properly modeled by a first square form followed by a short exponential waning phase attributed to the thermal inertia of the used halogen lamps. Finally, the simultaneous estimation of the remaining unknown parameters was carried out by minimizing the sum of the quadratic differences between the mathematical model and the measured thermogram on the back faces of the samples. The precision and accuracy of the apparatus results were also examined by measuring the thermal diffusivity of several homogeneous building materials. The standard deviation in thermal diffusivity for the studied samples doesn’t exceed 4.72 %. Then, five samples from clay mixed with different mass fractions of straw are prepared and their thermal diffusivities are measured. The thermal conductivity and the heat capacity of these composite materials are experimentally achieved and their values are reported for comparative purposes. The thermal characterization shows a decrease of about 27.5 % in thermal diffusivity, 43.32 % in thermal conductivity and 4.40 % in heat capacity versus the increase of the straw mass fraction.

Inexpensive Apparatus for High-Quality Imaging of Microbial Growth on Agar Plates.

The ability to capture images of results or processes is an important tool in the biologist’s tool kit. In microbiology, capturing high-quality images of microbial growth on agar plates is difficult due to the reflective surface of the plates and limitations in common photography techniques. Equipment is available to overcome these challenges, but acquisition costs are high. We have developed and tested an inexpensive and efficient apparatus for high-quality imaging of microbial colonies. The imaging box, as we have named the apparatus, is designed to eliminate glare and reduce reflections on the surface of the plate while providing uniform, diffuse light from all sides. The imaging box was used to capture hundreds of images in research and teaching lab settings.

Comparative experimental study of sand and binder for flowability and casting mold quality

A good sand mold is an indispensable prerequisite to obtaining a good metal casting. Although sand casting is one of the oldest metal forming technique known to humans, it still has a lot to discover. In a bid to meet the ever-growing demand for quality, economics and increasing environmental restrictions, research is still ongoing to optimize for example the process of making the sand mold. This paper presents a comparative study of six different foundry sands for flowability using simple inexpensive apparatus and some quality parameters achieved by these sands when used with three different types of binder, two organic and one inorganic. The study aims to facilitate the choice of mold materials with a more extensive outlook into their characteristics through a serious of sand and mold tests. A good comparison of already existing materials provides a good reference point when novel materials are investigated. All the sands exhibited ‘good’ flow property according to the simple flowability tests done. However, not the same consensus for flowability rank is reached by all the flow tests. The mold quality tests reveal the strength, loss on ignition and permeability values achieved with each of the binder and sand combination which can also be used in mold material selection.

Monitoring the formation of polyurethane foams with an infrared camera: Classroom activity

Foams prepared with polyurethanes (PU), a polymer with units in the main chain joined by urethane linkages, are commonly used in isolation panels, seals, automative seats, and bedding. The reaction causing the formation of polyurethane foams is a conventional, yet spectacular, way to attract the attention of polymer chemistry students. Infrared cameras are a relatively inexpensive apparatus that allow for semi-quantitatively temperature monitoring at the surface of objects. Because the formation of polyurethane is exothermic, the polymerization reaction and the expansion of the foam can be easily detected by an infrared camera. Information such as volume expansion, maximum temperature, temperature distribution in time and space, and reaction time can be retrieved from short videos. These data can be correlated and discussed in relationship with the reactivity of the components for synthesizing the foam. The primary goal of this activity was to investigate the exothermic reaction of polyurethane foam using an infrared camera which has been successfully used for monitoring the exothermic formation of polyurethane foams. These values can be discussed in term of reactivity of isocyanates (aromatic and aliphatic/cycloaliphatic) for a given formulation of polyols. The highly visual content of such experiments is attractive for children and students. Chemicals for performing the experiments can be donated either individually or as ready sets (“polyols”) from the industry. It is anticipated that the investment required for buying the infrared camera can be redeemed by using it for other types of exo- or endothermic reactions and for teaching heat transfer in physics class.

An inexpensive apparatus for up to 97% continuous-flow parahydrogen enrichment using liquid helium

Nuclear spin hyperpolarization derived from parahydrogen can enable nuclear magnetic resonance spectroscopy and imaging with sensitivity enhancements exceeding four orders of magnitude. The NMR signal enhancement is proportional to 4xp-1, where xp is the parahydrogen mole fraction. For convenience, many labs elect to carry out the ortho–para conversion at 77 K where 50% enrichment is obtained. In theory, enrichment to 100% yields an automatic three-fold increase in the NMR signal enhancement. Herein, construction and testing of a simple and inexpensive continuous-flow converter for high para-enrichment is described. During operation, the converter is immersed in liquid helium contained in a transport dewar of the type commonly found in NMR labs for filling superconducting magnets. A maximum enrichment of 97.3±1.9% at 30 K was observed at 4.5 bar and 300 mL/min flow rate. The theoretically predicted 2.9-fold increase in the signal enhancement factor was confirmed in the heterogeneous hydrogenation of propene to propane over a PdIn/SBA-15 catalyst. The relatively low-cost to construct and operate this system could make high parahydrogen enrichment, and the associated increase in the parahydrogen-derived NMR signals, more widely accessible.

A viability assay for individual Lactobacillus cells based on their electro-orientation between indium-tin-oxide electrodes

Lactic acid bacteria are widely used as probiotic products, making viability assessment of these bacteria an important parameter in the quality control procedures followed during the processing and preservation. In this study, we developed a rapid and easy single-cell viability assay for rod-shaped Lactobacillus casei that uses an alternating current (AC) electric field to induce electro-orientation (EO). Lactobacillus cells were sandwiched between two optically transparent indium-tin-oxide plate electrodes. An AC voltage of 2 V at 15 MHz was applied to a narrow electrode gap of 17 μm, corresponding to maximum cell length. We immediately identified opposite EO positions for living and dead cells using a light microscope; living cells stood upright, appeared as perfect dots, and oriented parallel to the electric field line, whereas dead cells lay flat, appeared as bars, and oriented perpendicular to the field. Besides saving time and labor, this method allowed easy viability estimation through automatic counting of dots or bars on the microscopic images using an image processing software. This simple and inexpensive apparatus provides a rapid and easy method for the assessment of the viability in Lactobacillus cells without chemical reagents.

Inexpensive apparatus for ultrasonographic examination of the nail unit and fingers

Inexpensive apparatus for ultrasonographic examination of the nail unit and fingers

Construction of virtual reality system for radiation working environment reproduced by gamma-ray imagers combined with SLAM technologies

The Fukushima Daiichi Nuclear Power Station (FDNPS), operated by Tokyo Electric Power Company Holdings, Inc., experienced a meltdown as a result of a large tsunami caused by the Great East Japan Earthquake on March 11, 2011. At that time, it was necessary to understand the aspects of the decommissioning working environment inside the FDNPS, such as establishing how the radioactive substances were distributed across the site, for work to be done efficiently without exposure to large amounts of radiation. Therefore, virtual reality (VR) emerged as a solution. There have been previous reports done on a technique for visualizing the distribution of radioactive substances in three dimensions utilizing a freely moving gamma-ray imager combined with simultaneous localization and mapping (SLAM) technology. In this paper, we introduce imaging technologies for the acquisition of image data from radioactive substances and three-dimensional (3D) structural models of the working environment, using a freely moving gamma-ray imager combined with SLAM technology. For this research, we also constructed a VR system and displayed the 3D data in a VR space, which enables users to experience the actual working environment without radiation exposure. In creating the VR system, any user can implement this method by donning an inexpensive head-mounted display apparatus and using a free, or low-cost, application software.

Highly efficient cataluminescence gas sensor for acetone vapor based on UIO-66 metal-organic frameworks as preconcentrator

Metal-organic frameworks (MOFs) showed a significant sorption potential in the gas capture and preconcentration during recent years because of its super porosity. Herein, we fabricated a simple and inexpensive home-made adsorption apparatus based on UIO-66 as the preconcentrator, which was firstly coupled with a rapid cataluminescence (CTL) sensor to determine acetone vapor. The CTL emission was enhanced by 25 times after the preconcentration of UIO-66, indicating the UIO-66 preconcentrator could efficiently ameliorate sensitivity. As for the adsorption mechanism of UIO-66 for acetone molecules, we deduced that acetone molecules were preferentially located on the Zr clusters with high hydrophilicity. The proposed CTL sensor in combine with UIO-66 adsorption granted a detection limit of acetone down to 2.79 ppm, and demonstrated good selectivity, simplicity, rapidity, and recyclability. This study provides appealing perspectives of UIO-66 as the preconcentrator for the improvement of analytical performance, and the prospect of a miniaturized portable acetone sensor.