Nylon Strings Research Articles

The Corrosion Behavior of Cnidoscolus aconitifolius (Chaya) Leaf Extract on Mild Steel in H2SO4 and Brine (NaCl Solution) Environments

The inhibition efficacies of extracts of Cnidoscolus aconitifolius (Chaya) leaves in the corrosion of mild steel were investigated in H2SO4, and NaCl media. Weight loss method was employed to determine corrosion rate. The ribbed mild steel rod was cut into forty (40) coupons, each measuring 16 mm (diameter) by 8 mm (length) and their initial weights taken and noted. Twenty (20) beakers containing 0.5M and 1.0M each of H2SO4 and NaCl solution separately with varying volumes of the extracts ranging from 5ml to 20ml were set up with four (4) coupons in each beaker fully immersed using nylon strings. The set up was allowed to stand for an exposure time of 672hrs with a coupon withdrawn from each beaker every 168 hours and processed using standard procedures before being reweighed using digital weighing balance. The weight difference for each coupon was obtained and used for corrosion rate calculation using the formula, CPR= K∆W/ρAt. Other corrosion parameters were also obtained using the relevant formulae: inhibition efficiency, IE%=(〖CR〗_c-〖CR〗_i)/〖CR〗_c ×100 and surface coverage, , θ=(〖CR〗_c-〖CR〗_i)/〖CR〗_c .The results obtained indicated that the normal corrosion rate profile for passivating metals was followed with the weight loss by the coupons being higher in the control media than those ones in the inhibited media. It was also observed that increase in volumes of these extracts from 5ml to 20ml decreased the corrosion rate of mild steel in the media. We found that in both media Cnidoscolus aconitifolius (Chaya) exhibited high inhibition efficiencies of 78.14% in H2SO4 and 64.15% in NaCl at extract concentration of 20 ml. Plots of the Langmuir adsorption isotherms suggest uniform surface covering of the adsorbent molecules at equilibrium state of the adsorbate–adsorbent system, with very strong adsorption forces. Based on these findings, the results suggest that Cnidoscolus aconitifolius (Chaya) leaves extract is a veritable green inhibitor for both acidic and salt media and can be a suitable alternative to the synthetic inhibitors widely used in the oil and gas industry.

The Inhibition Characteristics of Moringa oleifera Leaf Extract on Mild Steel in Tetraoxosulphate (VI) Acid and Sodium Hydroxide Environments

The inhibiting effects of Moringa oleifera leaves extract on the corrosion of mild steel in 0.5 M and 1.0 M both of H2SO4, and NaOH solution have been investigated using weight loss techniques. A total of 72 mild steel coupons of dimensions 10 mm x 5 mm x 5 mm were suspended using nylon strings in beakers containing the media with the leaf extract, obtained by Reflux method in concentrations of 5 ml, 10 ml, 15 ml and 20 ml respectively. The setup was allowed to stand for 28 days with a coupon withdrawn from each beaker at 7 days interval for corrosion analysis. The corrosion rate profiles showed behaviors similar to those of passivating metals that begins with a steep rise in corrosion rate and progressively decreases with increasing exposure time. However, it was noticed that at an exposure time of 14 days, the coupon in the 5 ml concentration experienced a sporadic rise in corrosion rate, which we attribute to the collapse of the passive film as a result of system agitation. The inhibition efficiency of the leaf in both media was significant, suggesting that it can be used as a green and eco-friendly alternative to the synthetic and rather hazardous inhibitors in use today. In conclusion, when compared, it was established that the inhibition potentials of the leaves were better in H2SO4 than in NaOH.

A Resonant Pulley Rotary Actuator for Scanning Capsule Endoscopy

We present a compact electromagnetically actuated 3D-printed rotary actuator for use in Scanning Capsule Endoscopy. The actuator comprises two cantilevers connected to a rotating body via nylon strings. External coils and the magnets placed on the cantilevers create an electromagnetic force with which the rotation can be initiated. Opposite coils are driven out-of-phase to enable resonant actuation. An electrical circuit model and finite element simulation results of the fundamental mode frequency are provided for the designed device. The design is manufactured via fused deposition modeling using polylactic acid (PLA) and thermoplastic polyurethane (TPU). Experimental results reveal a 98 ° total scan angle at 21 Hz resonance for the TPU actuator and a 19.7 ° total scan angle at 237 Hz resonance for the PLA actuator. Overall, the presented rotary actuator compares favorably over i) micromotor counterparts in terms of form factor (having a diameter of 13 mm and a total height of 7 mm) and ii) MEMS counterparts in terms of total scan angle. Manufacturing cost and duration are yet other benefits of the presented device, owing to 3D printing technique. With further development, the presented device can serve within a disposable capsule endoscopy unit for clinical use.

Diversity of the On-Farm Crop Dry Spell Adaptation Technologies in Isingiro Town Council, Isingiro District, Uganda

Isingiro Town Council is located within Uganda’s diagonal eco-region referred to as the “cattle corridor” and is synonymous with extreme climatic conditions, particularly dry spells, and intermittent floods (Egeru, 2016). Dry spells create a crisis among the highly rain-fed dependent farming Households (HH) in the study area. Some farming practices among HH are believed to contribute to Crop Dry Spell Adaptation (DSA). An exploratory survey was conducted to collect data from 125 crop farmers. The selection of respondents was through purposive and referral sampling methods in this study that were aimed at determining the diversity and extent of implementation of on-farm crop-specific Dry Spell Adaptation Technologies (DSATs) for major crops grown at the HH level. These include Bananas (98.4%), Beans (69.6%), Maize (43.2%) plus Fruits (4.0%) as per results from generated summary tables from Stata 14 analysis. 99.2% of the farmers who can define DSA are aware that some of their farming practices contribute to its attainment. DSATs for bananas include; up-rooting underground corms (75.2%), pruning (72.0%), de-suckering and pruning (70.4%), weeding before seeding (68.8%), mulching (67.2%) and staking with nylon strings or poles (64.0%) among others. DSAT for beans includes; strip/row planting with hoe weeding (68.8%), hoe weeding (68%), and beans-banana inter-cropping (16.8%) among others. strip/row planting with hoe weeding (44.8%), hand weeding (42.4%), and maize-banana inter-cropping (5.6%) among others. DSATs among fruits include; pruning and weeding and mulching each is implemented by 4.8% of the fruit farmers while spraying against flower abortion is done by 4%. planting with manure, watering/irrigation, and using water catchment basins each is implemented by 2.4% of the fruit farming HH among others. Farmers tend to implement diverse DSATs on crops where there they expected more Returns on Investment

Attenuation characteristics of tones and vibrations in guitars with nylon, fluorocarbon, and phosphor bronze strings pressed down against fret

Attenuation characteristics of tones and vibrations in guitars with nylon, fluorocarbon, and phosphor bronze strings pressed down against fret

Effectiveness of ecomodules in increasing aquatic biodiversity and bioproductivity in a port environment.

In early spring of 2018, so called ecomodules were attached to support piles of jetties within the polyhaline part of the port of Rotterdam. The objective of the ecomodules is to increase bioproductivity and biodiversity of the port basins and waterways, by ‘greening’ nautical infrastructure structures, which would otherwise support few species. An ecomodule consists of a coated steel construction of 1 meter wide and 4 meters high to which elements of structural diversity that facilitate the settlement and growth of organisms can be attached. About a quarter of the ecomodule protrudes above the water level at low tide, the other part is permanently under water. Five different types (I to V) of ecomodules have been tested. Ecomodules with: (I, cups, reference) tidal cups and a subtidal concrete reference slab, (II, ropes) used nylon hawsers with a diameter of 12 cm, (III, drainage pipes) drainage pipes sheathed with polypropylene with a diameter of 12,5 cm, (IV, fender hulas) bundles of thin nylon threads (untangled used hawsers), and (V roots) strands with 3 mm thick nylon strings with a length of 40 cm each. Monitoring of the ecomodules took place in the summers of 2018 and 2019.The biofouling on all ecomodules was zonate both inter- and subtidal. Different types of seaweed were found of which Ulva spec. occurred on all ecomodules while the large seaweed Fucus vesiculosus (Bladder wrack) only occurred on type II and IV. Amongst the macrofauna some groups/species clearly (co-)dominated the different types of ecomodules: barnacles and Crassostrea gigas (Pacific oysters) on type I, ascidians on type I, II, III and IV, hydrozoans on type II, III and V, bryozoans on type IV, while with a coverage of nearly 100% Mytilus edulis (Blue mussel) dominated type V.The ecomodules with elements of structural diversity vs the concrete reference plate scored higher on both biodiversity and bioproductivity. The total number of macrofaunal species found on the ecomodules ranged from 23 to 39 in order from lowest to highest number on respectively type, I (concrete reference plate), IV, V, II, III. The wet biomass on the ecomodules ranged from 5225 gr.m-2 to 80096 gr.m-2 in order from lowest to highest weight on respectively type, I (concrete reference plate), IV, III, II, V.We conclude that ecomodules can be an effective means to increase biodiversity and biomass in an aquatic environment consisting to a large extent of artificial structures, such as a port. An ideal ecomodule was designed based on the findings of the experiment and will be applied to mooring posts in a new project.

Building of Inmoov Robotic Arm for Performing Various Operations

Abstract: ‘Automation is the key in reducing the repetitive and banal tasks of everyday life’, the oft-quoted aphorism best portrays our effort at making a humanoid hand for tasks that require dexterity of fingers in situations where time and effort are of importance. The cost of human labor, quality of processes or products, time, and safety make this project a need of the hour. The research paper showcases our efforts of making a humanoid robotic arm. The body of the arm is composed of 3D printed parts. Servo Motors with nylon strings were used to control the fingers and the wrist. InMoov Nervo Board was used to control the servos. Worm Gear Mechanism was implemented to control the bicep movement and Worm Wheel is used for shoulder rotation. Machines can perform a wide range of functions without a considerable amount of human intervention. The future scope of Robotics and Automation would be to make a diverse and positive impact in industrial as well as research applications. Keywords: 3D Print, Build Challenges, Electronics, Humanoid, Inmoov, MyRobotLab, Robotic Arm, Robotics

The acoustics of a plucked harp string

The vibration response of a small harp is studied, by a combination of measurement, theoretical modelling and model-based sound synthesis. The harp’s distinctive angle between strings and soundboard is shown to have little impact on the results of linear modelling, but to have a significant effect on sound through a nonlinear phenomenon. Generation of axial force in the string through geometric nonlinearity is shown to produce very prominent effects, helped by the efficient coupling of longitudinal force to soundboard motion. The detailed pattern of the resulting “phantom partials”, already familiar from work on piano strings, is shown to be sensitive to the exact boundary condition between the string and the soundboard: better agreement between experiment and modelling is obtained by assuming a clamped boundary than a pinned boundary. It is suggested that the relative prominence of nonlinear effects in the harp, compared to other plucked-string instruments using non-metallic strings, may be one reason why harpists still prefer the sound of gut strings over nylon strings.

Comparison of Mechanical Properties of Natural Gut and Synthetic Polymer Harp Strings.

The long-term mechanical behaviour of a number of fluorocarbon and gut harp strings has been examined, and the results compared with a previous study of rectified nylon strings. The stretching behaviour of the three materials was studied via different measures of the Young’s modulus; with test time scales on the order of weeks, minutes, and milliseconds. The strings were subjected to cyclic variations in temperature, enabling various aspects of their thermal behaviour to be investigated. The effects of humidity changes on gut strings were also examined. The behaviour of the fluorocarbon strings was found to be similar in many ways to that of the nylon strings, despite their different chemical formulation and significantly higher density. In particular, the faster measures of Young’s modulus were found to show an almost identical strong variation with the applied stress; while the thermal behaviour of both materials was largely determined by the balance between opposing effects associated with thermal contraction and thermal variations in the Young’s modulus. The gut strings showed some similarities of behaviour to the synthetic materials, but also major differences. All three measures of the Young’s modulus remained constant as the applied stress was increased. The gut strings were far more sensitive to changes in humidity than the synthetic materials, although some of the results, especially the thermal tuning sensitivity of the strings when held at constant length, displayed remarkable stability under changing humidity. The observed behaviour suggests very strongly that there is significant coupling between humidity-related changes in the linear density of a gut string and complementary changes in its tension.

An Evaluation of Vertically Suspended Environmental Enrichment Structures during Rainbow Trout Rearing

AbstractEnvironmental enrichment is the addition of substrate or structural complexity to typically sterile culture environments, but the effects of enrichment on fish rearing performance are relatively unknown. This 127‐d study examined the growth and condition of juvenile Rainbow Trout Oncorhynchus mykiss reared in near‐fully covered circular tanks (1.8 m diameter) with three novel environmental treatments: (1) eight vertically suspended nylon strings with seven colored (6.4 cm diameter) plastic spheres (high density), (2) five vertically suspended strings with seven colored plastic spheres (low density), and (3) a mixture of five vertically suspended colored plastic spheres and nine vertically suspended aluminum rods. Near‐fully covered tanks without enrichment were used as a control. Weight gain, feed conversion ratio, individual fish length, and fish weight were significantly improved in environmentally enriched tanks compared with those features in the unenriched control. Among all of the treatments, the tanks of fish with high‐density spheres had significantly higher ending tank weights (i.e., total weight of fish in tank) and weight gain, both of which were nearly 65% and 75% greater, respectively, than in the control tanks. However, high density spheres also interfered with the self‐cleaning nature of the circular tanks. No significant differences in splenosomatic indices, viscerosomatic indices, hepatosomatic indices, and relative fin lengths were observed among the three enrichment treatments. Based on the results of this study, the use of either low‐density spheres or a mix of rods and spheres is recommended during the rearing of juvenile Rainbow Trout in circular tanks.

SPRAY DRIFT AND CATERPILLAR AND STINK BUG CONTROL FROM AERIAL APPLICATIONS WITH ELECTROSTATIC CHARGE AND ATOMIZER ON SOYBEAN CROP

ABSTRACT: The use of aerial application with electrostatic charge is an alternative to improve the quality of insecticide applications in soybean crop. The objective of this study was to evaluate the drift and chemical control of the caterpillar and stink bug complex promoted by aerial applications of insecticide in the soybean crop, using electrostatic spray system and rotary atomizers. The insecticide Thiamethoxam + Lambda cyhalothrin was applied with a Cessna 188 Ag Truck agricultural aircraft in two treatments: SPE® electrostatic system, with 54 SPE-5 nozzles and 10 L ha-1 application rate, and Travicar model® 05165 rotary atomizer, with 55° angle blades and application rate of 20 L ha-1. Drift was evaluated through quantification of active ingredient, by means of liquid chromatography, on nylon strings set 20, 40, 80, 160 and 320 m downwind from the applied area. Control efficiency was measured by counting caterpillars and stink bugs found five days after application. The droplet spectrum was also evaluated through water sensitive papers placed in the target area. It was verified that the hydraulic nozzles, associated with the electrostatic system, generated lower drift, but there was no difference in pest control efficiency, in relation to the rotary atomizers.

Influence of damping and nonlinearity in plucked strings: Why do light-gauge strings sound brighter?

When monofilament nylon strings of different tensions are used on a plucked instrument like the guitar or lute, it is readily observed that a lower-tension string tends to give a brighter sound. The elementary linear theory of a plucked string predicts no such effect. Linear theory can be extended to include bending stiffness and frequencydependent damping: Detailed measurements on a range of nylon strings are analysed to enable this extended model to be made quantitatively accurate. It is shown that a small influence of the string gauge is predicted, but synthesis based on this model does not match measurements or perceived differences of sound quality. Two nonlinear effects are then explored. The familiar effect of coupling between transverse and axial vibration in the string is shown to account for some observed features, but still does not explain the large difference of sound. The evidence from measurements strongly suggests that the mechanism responsible for the sound differences involves nonlinear interaction between the string and other parts of the structure, such as the frets. Because a lower-tension string tends to be played at larger amplitude, such buzzing interactions are more likely to occur. Implications for makers and players of instruments like the lute are discussed.

Wind tunnel flux comparisons using a phase Doppler interferometer

Abstract It is essential to know the movement of droplets in time and space (i.e. flux) when measuring and/or predicting spray drift in agricultural application. A study was performed to assess the flux measurements of a phase Doppler system against a standard monofilament system in a wind tunnel. The primary objectives of the study were to compare flux from a new phase Doppler system against 1.7 mm cotton and 2.0 mm nylon strings at varying wind speeds (1.4, 4.2, 8.3, 12.5, and 16.7 m · s−1) and spray exposures times (5, 10, 15, 30, and 60 s) with an overarching hypothesis that the active, phase Doppler is able to accurately measure the flux regardless of exposure and spray mass whereas the static string samplers are limited to a maximum retention. The phase Doppler did measure linearly as expected, however strings did not reach a point in which they loss mass; conversely, they appeared to overload with saturation. These findings are believed to be among many variables which influence the variability of previous mass balance studies.

Mechanical Properties of Nylon Harp Strings.

Monofilament nylon strings with a range of diameters, commercially marketed as harp strings, have been tested to establish their long-term mechanical properties. Once a string had settled into a desired stress state, the Young’s modulus was measured by a variety of methods that probe different time-scales. The modulus was found to be a strong function of testing frequency and also a strong function of stress. Strings were also subjected to cyclical variations of temperature, allowing various thermal properties to be measured: the coefficient of linear thermal expansion and the thermal sensitivities of tuning, Young’s modulus and density. The results revealed that the particular strings tested are divided into two groups with very different properties: stress-strain behaviour differing by a factor of two and some parametric sensitivities even having the opposite sign. Within each group, correlation studies allowed simple functional fits to be found to the key properties, which have the potential to be used in automated tuning systems for harp strings.

Fabrication of Lotus-Type Porous Copper Using Slip Casting and Sintering Techniques for Heat Pipe Applications

A lotus type-porous copper will be used to substitute wick materials from tabulate coral capillary for heat pipe applications. The lotus type-porous material are normally fabricated using Gasar process, in which unidirectional solidification was applied to the metal-eutectic systems to obtain long cylindrical pores in the direction of solidification. A new process is proposed to fabricate the lotus type-porous material using slip casting and sintering. As an initial work, this paper is aimed to obtain appropriate processing parameters of fabrication of lotus-type porous copper using slip casting and sintering techniques. Nylon strings were used as pore formers to form cylindrical pores. They were coated with copper slurry consisting of copper powder and binding agent. The coated nylon strings were arranged in a mold and the slurry were poured. After drying, these castings were sintered at various sintering temperatures and sintering times. The results showed that starch as the binding agent is superior to PVA. The mixture of starch-water with starch content of 97%, the copper slurry with copper content of 50% by volume, the copper powder size of 200 µm, the sintering temperatur of 900°C, and the sintering time of 60 minutes are able to produce lotus-type porous copper similar to that produced through Gasar process.

A Three-Dimensional-Printed Home-Based Flexible Nasopharyngeal Explorer With Diamond Cuts1

A Three-Dimensional-Printed Home-Based Flexible Nasopharyngeal Explorer With Diamond Cuts1

Adjuvantes na deriva de 2,4-D + glyphosate em condições de campo

O objetivo do trabalho foi avaliar o efeito de adjuvantes sobre a deriva em aplicações da mistura de 2,4-D + glyphosate. O experimento foi conduzido em condições de campo em delineamento inteiramente casualizado. Os tratamentos corresponderam às soluções com a mistura dos herbicidas 2,4-D + glyphosate (670 e 1068g ha-1, respectivamente) adicionando-se os adjuvantes (v v-1): óleo mineral (0,5%); agente antideriva (0,09%); espalhante adesivo A (0,1%); fertilizante líquido (0,05%); espalhante adesivo B (0,25%); e somente os herbicidas (testemunha). Foram utilizados para determinação de deriva fios de náilon externos à área de aplicação (1, 5, 10, 20, 50, 100 e 200m de distância) com quatro repetições e seis cilindros de espuma posicionados sobre a barra do pulverizador para coleta de gotas sujeitas à deriva. As aplicações foram realizadas simultaneamente, utilizando-se um sal traçador específico em cada solução de aplicação para quantificar os depósitos por meio de espectrofotômetro. Não foi possível verificar efeito dos adjuvantes sobre a deriva nas diferentes distâncias da área de aplicação. Com base nas gotas coletadas acima da barra de pulverização, constatou-se que a suscetibilidade à deriva foi menor com o óleo mineral e o agente antideriva. O risco de deriva foi maior com o fertilizante líquido e o espalhante adesivo B.

LIDAR as an alternative to passive collectors to measure pesticide spray drift

Pesticide spray drift entails a series of risks and costs in terms of human, animal and environmental well-being. A proper understanding of this phenomenon is essential to minimise these risks. However, most conventional methods used in drift measurement are based on point collectors which are unable to obtain information concerning the temporal or spatial evolution of the pesticide cloud. Such methods are also costly, labour-intensive, and require a considerable amount of time. The aim of this paper is to propose a method to measure the spray drift based on lidar (LIght Detection And Ranging) and to prove that it can be an alternative to passive collectors. An analytical model is proposed to relate the measurements obtained through passive collectors and those obtained with lidar systems considering several spray application and meteorological parameters. The model was tested through an experimental campaign involving multiple ground spray tests. A lidar system and two types of passive collectors (nylon strings and water-sensitive paper) were used simultaneously to measure the drift. The results showed for each test a high coefficient of determination (R2 ≈ 0.90) between the lidar signal and the tracer mass captured by the nylon strings. This coefficient decreased (R2 = 0.77) when all tests were considered together. Lidar measurements were also used to study the evolution of the pesticide cloud with high range (1.5 m) and temporal resolution (1 s) and to estimate its velocity. Furthermore, a very satisfactory adjustment (R2 = 0.89) was observed between the tracer mass collected by the nylon lines and the coverage on water-sensitive paper sheets. These results are in accordance with the proposed analytical model and allow the conclusion that the application and meteorological parameters can be considered spatially invariant for a given test but are not invariant for different tests.

Mechanical characteristics of strained vibrating strings and a vibration-induced electric field

The mechanical characteristics of vibrating strings strained between rigid supports and a vibration-induced electric field are studied. Experiments are conducted with nylon, rubber, and metallic strings. Vibrations are excited by a pinch at different sites along the string. The motion of the string is filmed, and the attendant electric field is detected. Experimental data are analyzed under the assumption that the field is induced by unlike charges generated by the moving string. It is found that the field allows one to determine the time characteristics of the motion of the string and discriminate the types of its deformations. Young moduli observed under the static extension of thin nylon strings are compared with those calculated from the natural frequencies of vibration measured for differently strained strings. The mathematical pattern of the motion of the string is compared with the real situation.

Pitch Analysis of Ukulele

Problem statement: The ukulele is a trendy instrument in the present day. It is a member of the guitar family of instruments which employs four nylon or gut strings or four courses of strings. However, a statistical analysis of the pitch of thi s instrument has not been conducted. To analysis pi tch or fundamental frequency of its main cords should be p erformed in an appropriate way. This study brings about its effective sound synthesis which is an imp ortant issue in the future. Approach: An efficient technique for the analysis of the fundamental frequ ency (F0) of the human speech had been applied to t he analysis of main cords of the ukulele. The autocorr elation-based technique was used with the signal waveform to extract the optimal period or pitch for the corresponding analyzed frame in time domain. Then the corresponding fundamental frequency was calculated in the frequency domain. Results: The 21 main cords were chosen in the study. It had been seen th at the existing fundamental frequency values were v aried from one to three values. The value was ranging fro m 65.42 Hz-329.93 Hz. Conclusion: By using the analysis technique of fundamental frequency of the human speech, the output frequencies of all main co rds can be extracted. It can be empirically seen that t hey have their unique values from each others.