Environmental Humidity Control Research Articles

Realizing Phase‐Pure (PEA)2FAPb2I7 Perovskite Films by Inhibiting 3D Phase Formation

Abstract2D Ruddlesden–Popper (RP) layered metal‐halide perovskites have garnered significant interest due to their unique photoelectric properties and excellent stability. However, 2D perovskite films prepared via solution process generally exhibit multi‐quantum well structure with random well width distribution, which significantly impedes the carrier transportation. Herein, the synthesis of phase‐pure 2D (PEA)2FAPb2I7 (PEA = C8H11N, FA = CH4N2) perovskite thin films is reported in ambient environment achieved by suppressing the formation of the 3D perovskite phase. First, incorporation of MACl additive can effectively regulate the intermediate during crystallization, facilitating the formation of a metastable 3D MAxFA1‐xPbIyCl3‐y phase. Second, precise control of environmental humidity is employed to further inhibit the formation of α‐FAPbI3 phase. As a result, the perovskite intermediate composed of predominantly metastable 3D phase and 2D n = 2 phase is achieved, which is eventually transformed into 2D n = 2 perovskite during annealing, leading to markedly enhanced phase purity. Photoconductive‐type photodetectors based on the phase‐pure 2D RP perovskite films are fabricated, demonstrating a high detectivity of over 9.4 × 1012 Jones due to the improved carrier transportation. This study provides a comprehensive insight into the crystallization process of phase‐pure 2D perovskites.

Recycling of cathode ray tubes and stone sludge for the synthesis of Al-MCM-41 grafted amine functional group and environmental humidity control material applications

There is a growing need for economical methods by which to reuse industrial waste. This paper reports on the recycling of industrial waste in the preparation of amine functionalized mesoporous molecular sieves (Al-MCM-41), for use as a building material applicable to the energy-free regulation of indoor humidity. The preparation of amine functionalized Al-MCM-41 for experiments involved combining stone sludge, cathode ray tube panel waste glass, an alkali agent (sodium hydroxide), and cetyltrimethylammonium bromide with aminopropyltriethoxysilane in various proportions. The water vapor adsorption of amine functionalized Al-MCM-41 (42.85 g/m2) far exceeded of amine functionalized Al-MCM-41 without surface grafting (28.64 g/m2). Al-MCM-41 with 2.5 vol% amine functional groups achieved the highest 24-h water vapor adsorption performance in compliance with JIS A 1470 standards. This research provides an economical approach to the recovery and recycling of industrial waste that is rich in silicon and aluminum.

Humidity Control Scheme for Chicken Chick Banda for Improved Performance using Particle Swarm Optimization

The research is about developing of prototype Humidity control unit of a chicken chick Banda for maximum reduction in energy wastage and ensuring conducive environmental condition for bird’s growth and development using the proportional integral differential (PID) controller and the particle swarm optimization (PSO) technique for comparison purposes. The PSO stated here in is a stochastic optimization method working on the movement of swarm so as to achieve convergence. The study is achieved through designing of a prototype of the humidity environment controller to achieve two states or conditions that is for the controlled case and for the uncontrolled case. Environmental humidity control is achieved using a programmed Arduino and the DC FAN. The process is then designed using the MATLAB simulation software operating at the Simulink model designing platform. The same design is connected to the PID controller and then also tuned using the PID tuning platform on the Matlab. The same design is implemented on the workspace using particle swarm optimization method and it is then run to see the system behavior in terms of settling time, rising time and peak overshoot. The major reason of the study is to demystify the myth that one can only use conventional PID controller techniques in performance improvement and that there is a better method which can similarly be used with better results and cheaper. Most poultry farmers are stack with their old ways of achieving good performance therefore the results of this work will be an eye opener for them to embrace new techniques in the market The presented particle swarm optimization techniques shows impressive performance in terms of the settling time, rise time and over shoot.

Environmental humidity control method for structural reading and writing based on micropipette probe

Environmental humidity control method for structural reading and writing based on micropipette probe

Failure analysis on pre-corroded specimens of Inconel alloy 718, under ultrasonic fatigue tests at room temperature

This work deals with the pre-corrosion effects on the ultrasonic fatigue endurance failure of Inconel alloy 718 (I-718), and on crack initiation and propagation at room temperature. Pre-corrosion was induced using the international standard ESA ECSS-Q-ST-70-37C of the European Space Agency. The base and pre-corroded specimens were tested under the ultrasonic fatigue technique at frequency of 20 kHz, room temperature, without control of environmental humidity and with the load ratio R = -1. The results of ultrasonic fatigue endurance show that at higher levels of stresses, up to 746 MPa, the pre-corroded specimens show a lower fatigue endurance with a factor of 10 approximately, compared with the base material. In addition, the principal trends of pitting at the specimen neck section were reproduced by numerical models in order to investigate the stress concentration factors and its impact in fatigue endurance. Finally, the stress intensity factor in mode I was evaluated numerically at the specimen neck section from crack initiation to fracture and the stress intensity factor range threshold ΔKTH was obtained for the two type of tested specimens, together with the number of cycles in the “Stable Zone of Crack Growth”, for both types of specimens.

Sorption cable sensor with large sensing range and fields of its application

The paper discusses the existing approaches to the use of point and cable sensors to control leaks and humidity. The principal disadvantages of monitoring systems based on them are shown: when detecting leaks, there is a delay in the response time due to the condition of fluid accumulation around the sensors; when controlling the humidity of extended environments, it becomes necessary to install a large number of point sensors with individual switching channels; there is no universal sensor for monitoring leaks and humidity. An alternative solution is proposed - a sorption cable sensor with a large sensitivity range, which, as a leak detector, can be placed anywhere in 3D space where leakage is most likely, and as a linear humidity sensor, it can replace point sensors in an extended control zone. The research results of the developed cable sensors confirm their high sensitivity, speed and relaxation ability to recover (dry) after leaking. The areas of application considered in the article, examples of the implementation of a sorption cable sensor in a system for monitoring leaks and air humidity of computing nodes with liquid cooling of Russian supercomputers testify to the high efficiency and development potential. Based on sorption cable sensors, it is possible to build effective systems for early detection of leaks by the first signs of their manifestation, environmental humidity control systems and universal leakage control systems, steam breakthroughs and the level of relative humidity. Reducing the time for detecting leaks and steam breakthroughs will allow taking preventive measures to prevent the development of damage, and the use of cable humidity sensors instead of distributed point sensors will dramatically reduce the cost of organizing humidity monitoring of extended environments.

An Effective and Convenient Way to Improve the Adhesion Property of the Dental Zirconia Prosthesis by Ar Plasma Jet With the Control of Environmental Humidity

Argon plasma jet is applied to the dental zirconia prosthesis to improve its hydrophilicity, so as to enhance its adhesion property. The relationship among the environmental humidity, hydrophilicity, and adhesion property of zirconia is investigated. The results show that the $\cdot $ OH density, which mainly results from the electron excitation temperature and metastable Ar atom, is affected by the environmental humidity, and there are remarkable decrease in carbon content and increase in oxygen-containing functional groups on zirconia surface, which is induced by the $\cdot $ OH. In addition, it is observed that the surface morphology is changed by the plasma. The double effects of functional groups and surface morphology contribute to the hydrophilicity of zirconia. Meanwhile, the hydrophilicity has an impact on the adhesion property of zirconia. The plasma treatment with the environmental humidity of 59.4% achieves the best results in this paper. It reduces the water contact angle to the minimum value of 3.4°±0.6° and brings an improvement of 50% in the bonding strength of zirconia. In order to apply the research achievements perfectly to practice, the environmental humidity has to be fixed at 59.4%. In fact, it is very difficult to precisely control. Hence, the shear bond strength test at the environmental humidity of 54%–66% is carried out. The results show that the shear bond strength of zirconia maintains at approximately 137.5%. This means that the variation of humidity in small scale has a little influence on the shear bond strength.

Ultrasonic fatigue on the automotive steels: AISI/SAE 4140T and 1045

Ultrasonic fatigue tests were carried out on two automotive steels: AISI/SAE 4140T and 1045, to investigate the fatigue endurance of these materials and the mechanisms of crack initiation and propagation under this modality of loading. Tests were obtained at room temperature and without control of environmental humidity; the last parameter was maintained between 50 and 65%.Ultrasonic fatigue results show that the effect of non-metallic inclusions plays an important role in the decay of fatigue endurance for the 4140T steel, together with the effect of previous heat treatments. Concerning1045 steel, non-metallic inclusions play an important role too, but this time the temperature and variation of ductility with temperature induce an effect on the ultrasonic fatigue endurance. Finally, the fracture surfaces were analyzed in order to obtain the principal trends of crack initiation and propagation on these steels, under the ultrasonic loading modality.

Internal Hydration Properties of Single Bacterial Endospores Probed by Electrostatic Force Microscopy.

We show that the internal hydration properties of single Bacillus cereus endospores in air under different relative humidity (RH) conditions can be determined through the measurement of its electric permittivity by means of quantitative electrostatic force microscopy (EFM). We show that an increase in the RH from 0% to 80% induces a large increase in the equivalent homogeneous relative electric permittivity of the bacterial endospores, from ∼4 up to ∼17, accompanied only by a small increase in the endospore height, of just a few nanometers. These results correlate the increase of the moisture content of the endospore with the corresponding increase of environmental RH. Three-dimensional finite element numerical calculations, which include the internal structure of the endospores, indicate that the moisture is mainly accumulated in the external layers of the endospore, hence preserving the core of the endospore at low hydration levels. This mechanism is different from what we observe for vegetative bacterial cells of the same species, in which the cell wall at high humid atmospheric conditions is not able to preserve the cytoplasmic region at low hydration levels. These results show the potential of quantitative EFM under environmental humidity control to study the hygroscopic properties of small-scale biological (and nonbiological) entities and to determine its internal hydration state. A better understanding of nanohygroscopic properties can be of relevance in the study of essential biological processes and in the design of bionanotechnological applications.

Role of Absorbed Solvent in Polymer Pen Lithography

We report on the dynamic role of solvents in molecular printing and show that material transport can be mediated by both environmental solvent (i.e., humidity) and solvent absorbed in the pen. To explore the transport of materials in the absence of environmental solvent, a hydrophobic polymer was patterned using a polydimethylsiloxane (PDMS) pen array that had been soaked in undecane, a nonpolar solvent that readily absorbs into PDMS. We also explored the patterning of the hydrophilic polymer polyethylene glycol (PEG) and found that, even though PDMS only absorbs trace amounts of water, soaking a PDMS pen array in water enables PEG deposition in completely dry environments for over 2 h. We find that the length of time one can pattern in a dry environment is determined by the availability of absorbed solvent, a relationship that we elucidate by comparing the performance of pens with varying ability to absorb water. Furthermore, a calculation accounting for the dynamics of retained water captures these effects completely, allowing for generalization of this result to other solvents and providing a way to tune the desired solvent retention profile. Taken together, this work explores the subtle and dynamic role of solvent on molecular printing and provides an alternative to strict environmental humidity control for reliable molecular printing.

Fatigue endurance and crack propagation under rotating bending fatigue tests on aluminum alloy AISI 6063-T5 with controlled corrosion attack

Rotating bending fatigue tests were carried out on the aluminum alloy 6063-T5 for pre-corroded and non corroded specimens. Special attention was devoted to fatigue endurance reduction induced by controlled surface corrosion on testing specimens. Corrosion attack was obtained by immersion of specimens in an acid solution for: two, four and six minutes in order to induce three degrees of surface corrosion. The corrosion agent was a solution of hydrochloric acid with a pH close to 0.8 and solution concentration of 38%. Rotating bending fatigue tests at the frequency of 75Hz, room temperature and without environmental humidity control were carried out on the pre-corroded and non corroded specimens in order to investigate the corrosion effect on the fatigue endurance and the stress intensity factor range threshold. Additionally, numerical crack propagation investigation was carried out using a 2D model for testing specimen and the Displacements Correlation Method (DCM). A Kitagawa–Takahashi diagram for this aluminum alloy is developed in the last section of this work; it was obtained with experimental results. Finally, conclusions are listed concerning rotating bending fatigue tests, crack propagation and fatigue-corrosion behavior of this material.

Effect of Controlled Corrosion Attack With HCl Acid on the Fatigue Endurance of Aluminum Alloy AISI 6063-T5, under Rotating Bending Fatigue Tests

ABSTRACTCorrosion attack is implemented on the aluminum alloy AISI 6063-T5 for six different non corroded and pre-corroded specimens. Concerning pre-corroded specimens, they are divided in two groups; the first one is immersed for 1 and 2 minutes in hydrochloric acid with 20% concentration, and the second group for 2, 4, 6 minutes of immersion but in HCl with 38% of concentration. Rotating bending fatigue tests are carried out on corroded and non-corroded specimens at the frequency of 50 Hz, at room temperature and without control of environmental humidity. Loading conditions are fixed by Finite Element numerical simulation; the loading ranges are 90%, 80%, 70% and 60% of the yield stress of this aluminum alloy. A numerical simulation study is carried out by means of the Ansys software to investigate the stress concentration factor variation induced by the proximity of two close pitting holes: in longitudinal and transversal direction regarding the principal applying loading. Finally, optical microscopy is used to analyze the fracture surfaces in longitudinal and transversal directions, in order to establish possible causes of fatigue fracture.

Rotating Bending Fatigue Endurance and Effect of Controlled Corrosion on the AISI-SAE 6063-T5 Aluminum Alloy.

ABSTRACTRotating bending fatigue test are carried out on the aluminum alloy 6063-T5 for corroded and non corroded specimens. Special attention is devoted to fatigue endurance reduction caused by controlled surface corrosion on corroded specimens. Corrosion attack is implemented by submersion of specimens in an acid solution for: two, four and six minutes in order to induce three degrees of surface corrosion. The corrosion agent is a solution of hydrochloric acid with a PH close to 0.8 and solution concentration of 38%. Rotating bending fatigue tests at frequency of 50 Hz, room temperature and without environmental humidity control are carried out on 4 types of specimens: without corrosion and 2, 4, and 6 minutes immersed in the solution of hydrochloric acid. Results are analyzed regarding the corrosion effect on fatigue endurance and conclusion are enlisted concerning rotating bending fatigue tests and corrosion attack on this aluminum alloy.

Studies on the Function of Environmental Humidity Control of Textiles. (Part 5). Relation between Function of Environmental Humidity Control and Moisture Sorption-Desorption Isotherm in Polyacrylic Acid Fibers.

The relation between the function of environmental humidity control (B-value) and the moisture sorption-desorption isotherm was mainly studied for the polyacrylic acid fibers having a ultra-high moisture content of 20 to 40wt%. The change of the moisture content of specimen (Δm) in a closed vessel under periodic change of temperature between T1 and T2 (T1<T2) was given as the difference between moisture contents along the moisture sorption isotherm at T1 and desorption isotherm at T2. Based on this fact, the relation curve between B-value and the weight of specimen for the volume of closed vessel(W0/V) calculated from the moisture sorption-desorption isotherm agreed well with the observed one. This means the fiber products having the desired B-value can be designed from the moisture sorption-desorption isotherm of the constituent fibers.

Studies on the Function of Environmental Humidity Control of Textiles. (Part 4). Function of Environmental Humidity Control of Polyacrylic Acid Fibers.

The function of environmental humidity control(B-value) of ultra-high moisture absorbing materials was evaluated using polyacrylic acid fibers. The curve of B-value at 7.5g/V as a function of moisture absorption was as follows: B-value was markedly increased from -0.0236 to -0.0100/°C with increase of moisture content from 0 to 10 wt%, linearly increased for the moisture content from 10 to 40wt% and shown -0.0012/°C at 40wt%. The PAA-3 fiber showing ultra-high moisture content of about 40wt% attained the B-value=0/°C at 15.0g/V. Furthermore, B-values of the mixed fibers, composed of PAN or Cotton of 30 wt% and PAA-2 fiber of 70wt%, were observed as a function of their weight (g/V) and discussed with the relation to the B-values of their components.

Studies on the Function of Environmental Humidity Control of Textiles. (Part 3). Function of Environmental Humidity Control of Commodity Textiles.

The function of environmental humidity control (B-value) of Nylon6 fabric, Rayon fabric and Tencel fabric was evaluated as the representative of commodity textiles showing a moisture sorption-desorption. B-value of these textiles was depending on their moisture sorption: the nearly same value as Woolen fabric for Rayon fabric, the somewhat higher value than Cotton fabric for Tencel fabric and the considerably lower value than Cotton fabric for Nylon6 fabric were obtained at the specimen's weight of 0 to 20g/a volume of closed vessel (V=0.012m3). The change of moisture sorption in each textile during measurement of B-value was given as the difference between the moisture sorption isotherm at the side of lower temperature (25°C) and the moisture desorption isotherm at the side of higher temperature (35°C) . Based on this fact, the calculated relation curve of B-value and specimen's weight (g/V), using the moisture sorption isotherm at 25°C and the moisture desorption isotherm at 35°C, agreed well with the observed one.Furthermore, the B-values at 7.5g/V of a mixture composed of various fabrics including fabrics in previous paper [Sen'i Gakkaishi, 52, 234 (1996)], basically, was given as the average value with a mixed ratio of the B-value at 7.5g/V of its each component. Moreover, even if the relation curves of B-value and Wo/V between each component in a mixture was markedly different, it was given as the conversion B-value for a kind of component which was determined in this paper.

Relation between Function of Environmental Humidity Control and Moisture Sorption-Desorption Isotherm in Moisture Sensitive Textiles.

The relation between the change in moisture content during the measurement of B-value and the moisture sorption-desorption isotherm was studied for the moisture sensitive textiles of cotton fabric, woollen fabric and NF-38 non-woven fabric. The change of the moisture content in a closed vessel under periodic change of temperature between T1 and T2 agreed well with the difference between the moisture contents along the moisture sorption isotherm at lower temperature T1 and desorption isotherm at higher temperature T2. The calculated relation curve, based on this finding, between B-value and weight of each textile for the volume of a closed vessel agreed well with the observed one. This means the textiles having the desired B-value can be designed from the moisture sorption-desorption isotherm of the constituent fibers.

Evaluation with B-value of the Function of Environmental Humidity Control of Textiles.

B-values of various moisture-absorbing textiles and usual interior materials such as lauan plywood were analyzed as a measure of the function of environmental humidity control, by measuring the continuous change of relative humidity accompaning with the periodic change of temperature in a closed vessel of 0.012 m3 including a textile or a usual interior material having a constant area or weight. The response of moisture-absorption (or-desorption) of each textile was quicker than that of lauan plywood for interior wall, so as to follow the change of relative humidity caused by the rapid change of temperature in a closed vessel. This is due to the markedly large specific surface area in a textile, concerning with the moisture-absorption (or-desorption), in comparison with that in a lauan plywood. The B-values determined at the constant area for each textile were lower than that of a lauan plywood, that is, the function of environmental humidity control of each textile was inferior to that of a lauan plywood. However, B-values at the constant weight for a cotton fabric, a woollen fabric, a rayon fabric and a solvron fabric were almost the same degree with that of lauan plywood. In B-values at the constant weight for these materials, the higher moisture-absorption led to the higher B-value. The highest moisture-absorption and the highest B-value were observed in the NF-38 non-woven fabric, 60 wt% of which was the high moisture-absorption fiber N-38. These results show that the function of environmental humidity control of materials, having a large and different specific surface area, should be evaluated by B-value at the constant weight and that the textiles having a superior function of environmental humidity control, exceeding that of lauan plywood, can be designed by controlling the weight/area of moisture-absorption textiles such as a cotton fabric.