Kp Values Research Articles

Characterization and health risks of short- and medium-chain chlorinated paraffins in the gas and size-fractionated particulate phases in ambient air

Short-chain and medium-chain chlorinated paraffins (SCCPs and MCCPs) have garnered significant attention because they have persistence and potential toxicity, and can undergo long-distance transport. Chlorinated paraffins (CPs) inhaled in the size-fractionated particulate phase and gas phase can carry different risks to human health due to their ability to accumulate in different regions of the respiratory tract and exhibit varying deposition efficiencies. In our study, large-volume ambient air samples in both the size-fractionated particulate phase (Dp < 1.0 μm, 1.0–2.5 μm, 2.5–10 μm, and Dp ≥ 10 μm) and gas phase were collected simultaneously in Beijing using an active sampler. The overall levels of SCCPs and MCCPs were relatively high, the ranges being 57–881 and 30–385 ng/m3, respectively. SCCPs tended to be partitioned in the gas phase (on average 75% of the ΣSCCP concentration), while MCCPs tended to be partitioned in the particulate phase (on average 62% of the ΣMCCP concentration). Significant correlations were discovered between the logarithm-transformed gas–particle partition coefficients (KP) and predicted subcooled vapor pressures (PL0) (p < 0.01 for SCCPs and MCCPs) and between the logarithm-transformed KP values and octanol–air partition coefficients (KOA) (p < 0.01 for SCCPs and MCCPs). Thus, the slopes indicated that organic matter absorption was the dominant process involved in gas–particle partitioning. We used the ICRP model to calculate deposition concentrations for particulate-associated CPs in head airways region (15.6–71.4 ng/m³), tracheobronchial region (0.8–4.8 ng/m³), and alveolar region (5.1–21.9 ng/m³), then combined these concentrations with the CP concentrations in the gas phase to calculate estimated daily intakes (EDIs) for inhalation. The EDIs for SCCPs and MCCPs through inhalation of ambient air for the all-ages group were 67.5–184.2 ng/kg/day and 19.7–53.7 ng/kg/day, respectively. The results indicated that SCCPs and MCCPs in ambient air do not currently pose strong risks to human health in the study area.

Determining PID Parameters For Temperature Control System in Cavendish Banana Storage Room

Banana is one of the most popular fruits in Indonesia, and its freshness will be the top priority for consumers in choosing it. After packaging, special treatment needs to be done in the banana storage room. One of them is to keep the temperature of the storage room stable. The temperature of the room between 5oC to 10oC is the ideal temperature for storing bananas, the Control system offered is PID with the Ziegler-Nichols method to get the values of Kp, Ki and Kd. Determination of Kp, Ki and Kd values is very important to get good system stability and a small error. The tuning rule of Ziegler-Nichols 1 method can be applied to obtain the values of Kp, Ki and Kd. With several steps taken, the values of L = 90s and T = 206s are obtained and referring to the Ziegler-Nichols 1 table, the values of Kp = 2.7, Ki = 0.015 and Kd = 121.5 are determined.

Fabrication and physical properties of Na(Nb1-xSbx)O3 templates for the [001]-texturing of KNN-based ceramics

Na(Nb1-xSbx)O3 [N(N1-xSx)] templates were fabricated to texture the 0.96(Na0.5K0.5)(Nb1-ySby)O3-0.01BaZrO3-0.03(Bi0.5Ag0.5)ZrO3 [KN(N1-ySy)-BZ-BAZ] piezoceramics along the [001] direction. To the best of our knowledge, this is the first study that fabricated these templates. Thus far, NaNbO3 (NN) templates have been utilized to texture KNN-modified piezoceramics; however, they produce many holes in the piezoceramics because of the dissolution of the NN templates during sintering. N(N0.9S0.1) templates with an average size of ∼18 μm were produced by the molten-salt and topochemical methods utilizing Bi2.5Na3.5(Nb0.9Sb0.1)5O18 precursors. Due to their high melting temperature, the N(N0.9S0.1) templates did not dissolve during sintering. Therefore, no holes were present in the KN(N0.95S0.05)-BZ-BAZ piezoceramic textured using the N(N0.9S0.1) templates. The piezoceramic textured using the N(N0.9S0.1) templates showed a large hardness (7.56 ± 0.26 GPa) and an elastic modulus (154 ± 5 GPa) similar to those of the untextured piezoceramic. However, the piezoceramic textured using the NN templates showed reduced hardness (5.94 ± 0.58 GPa) and elastic modulus (127 ± 14 GPa) because of the presence of the holes. The KN(N0.95S0.05)-BZ-BAZ piezoceramics textured using the N(N0.9S0.1) templates provided large d33 (740 pC/N) and kp (0.62) values. Cantilever-type piezoelectric energy harvesters (CPEHs) were produced using the KN(N0.95S0.05)-BZ-BAZ piezoceramic textured with N(N1-xSx) templates and the CPEH produced using the piezoceramic textured by N(N0.9S0.1) templates generated the largest power of 2.92 mW. Therefore, N(N0.9S0.1) is a promising template for the [001] texturing of KNN-based piezoceramics with good mechanical properties.

Development of Novel Methods for QSAR Modeling by Machine Learning Repeatedly: A Case Study on Drug Distribution to Each Tissue.

Artificial intelligence is expected to help identify excellent candidates in drug discovery. However, we face a lack of data, as it is time-consuming and expensive to acquire raw data perfectly for many compounds. Hence, we tried to develop a novel quantitative structure-activity relationship (QSAR) method to predict a parameter more precisely from an incomplete data set via optimizing data handling by making use of predicted explanatory variables. As a case study we focused on the tissue-to-plasma partition coefficient (Kp), which is an important parameter for understanding drug distribution in tissues and building the physiologically based pharmacokinetic model and is a representative of small and sparse data sets. In this study, we predicted the Kp values of 119 compounds in nine tissues (adipose, brain, gut, heart, kidney, liver, lung, muscle, and skin), although some of these were not available. To fill the missing values in Kp for each tissue, first we predicted those Kp values by the nonmissing data set using a random forest (RF) model with in vitro parameters (log P, fu, Drug Class, and fi) like a classical prediction by a QSAR model. Next, to predict the tissue-specific Kp values in a test data set, we constructed a second RF model with not only in vitro parameters but also the Kp values of other tissues (i.e., other than target tissues) predicted by the first RF model as explanatory variables. Furthermore, we tested all possible combinations of explanatory variables and selected the model with the highest predictability from the test data set as the final model. The evaluation of Kp prediction accuracy based on the root-mean-square error and R2 value revealed that the proposed models outperformed other machine learning methods such as the conventional RF and message-passing neural networks. Significant improvements were observed in the Kp values of adipose tissue, brain, kidney, liver, and skin. These improvements indicated that the Kp information on other tissues can be used to predict the same for a specific tissue. Additionally, we found a novel relationship between each tissue by evaluating all combinations of explanatory variables. In conclusion, we developed a novel RF model to predict Kp values. We hope that this method will be applied to various problems in the field of experimental biology which often contains missing values in the near future.

Effect of crystal structure on the improvement of the piezoelectric properties for [001]-textured PZT-PNN piezoceramics

Ceramics with a coexisting rhombohedral-tetragonal (R-T) structure, 0.53 Pb(Zr1-xTix)O3-0.47 Pb(Ni1/3Nb2/3)O3 [CP(Z1-xTx)-PNN] (x = 0.57 and 0.66) containing 1.0 mol% CuO, are textured along the [001] direction using BaTiO3 (BT) templates. The CP(Z1-xTx)-PNN ceramics achieve effective [001] texturing at 1250 °C, as evidenced by a high Lotgering factor (>94%) utilizing 3.0 vol% BT templates. CuO reduces the sintering temperature but does not assist in the texturing of the specimen at low temperatures. Adding a large amount of BT templates reduced the piezoelectric properties of the specimens. The study reveals untextured CP(Z0.43T0.57)-PNN ceramic with low d33 (370 pC/N) and kp (0.49) values exhibiting substantial improvement in these properties (920 pC/N and 0.65, respectively) post-[001] texturing, attributed to the high R structure content (60%). Conversely, the untextured CP(Z0.34T0.66)-PNN ceramic, showing higher d33 (740 pC/N) and kp (0.63) values, experiences a reduction in these parameters to 480 pC/N and 0.52, respectively, after [001] texturing due to a lower content of the R structure (21%). Consequently, the study suggests that piezoceramics with a higher content of the R structure are more favorable for enhancing piezoelectric properties through [001] texturing.

Development of an IoT-Based Egg Incubator with PID Control System and Web Application

The rapid development of technology significantly impacts various aspects of life, including the field of livestock farming. The advancement of technology is expected to enhance the rate and effectiveness of production, particularly in the hatching of chicken eggs or chick breeding. The existing technology relies on manual on/off systems and manual monitoring, hindering successful egg-hatching rates and percentages. Therefore, this research aims to explain the development of an automated egg incubator using a Proportional Integral Derivative (PID) control system with hypertuning parameters, as well as temperature and humidity monitoring, along with a protection system based on voltage sensors, all integrated with the Internet of Things (IoT). The PID control is employed to regulate the temperature of the egg incubator, ensuring stability according to the predetermined set point temperature. The IoT system in this study comprises an ESP32 node as a microcontroller connected to a sensor, using Firebase and User app for monitoring the egg incubator. The study employed PID control with parameter values Kp=10, Ki=3, and Kd=8. The research yielded time-efficient egg incubation and prevention of turning delays. The DHT21 sensor achieved a 90% success rate in detecting room temperature (38°C) and humidity (77%-84%) within the incubator, while PID control effectively maintained the target temperature. The ACS712 sensor accurately detected current in the heater, power supply, and motor. The Kodular application can display sensor readings. The future implication is developing a more adaptive PID method toward changes and nonlinear dynamics.

IDENTIFICATION OF PHYSICOCHEMICAL PROPERTIES, PHARMACOKINETICS AND TOXICITY OF ACTIVE COMPOUNDS OF Kaempferia galanga RHIZOME

The Kencur plant has many benefits, is economically valuable, and is widely cultivated by the local community. The development of kencur compounds has not been carried out optimally because of the relatively high cost of identifying the content of each compound. This study aimed to determine the physiochemical properties of kencur compounds and their pharmacokinetics, as well as the toxicity of the herb kencur rhizome in silico. The method used in this study uses a Marvin sketch to draw the structure of the compound, which was then analyzed using Lipinski to determine its physico-chemical properties. Pharmacokinetic and toxicity analyses were performed using the pKCSM software. The results showed that all compounds followed Lipinski's rules; therefore, predictably, they could be developed into drug molecules from these compounds. In addition, all compounds had fairly high Water Solubility (log S). All HIA compounds were &gt;90%, so they were well absorbed in the intestine and showed good permeability to CaCO-2 with a log Papp value of &gt; 0.90. All the above compounds have low permeability to the skin due to the log Kp value &gt; -2.5, so they are not suitable for transdermal preparations. Keywords: Physicochemistry, Pharmacokinetics, Toxicity, Kencur, In silico

Abstract 7163: Pharmacokinetics assessment of intranasal NEO100 treatment on blood-brain barrier disruption and brain penetration of drugs in rodent brain

Abstract Background: Insufficient drug concentrations reaching the brain-localized tumor tissue remains one of the major challenges in the treatment of glioblastoma (GBM). An intranasal (IN) formulation of NEO100 (NeOnc Technologies, Inc., Los Angeles), a highly purified version of perillyl alcohol, has been recently reported to enhance drug concentrations in the brain upon IN co-delivery. Here, we report detailed pharmacokinetics (PK) and tissue analysis to quantitatively examine the extent of increase in drug concentrations in the brain after IN NEO100 administration. Furthermore, we also confirmed that IN NEO100 increases brain drug concentration by circumventing the blood brain barrier. Method: For PK analysis, either IN or oral formulation of a three-drug cocktail (ZEI, consisting of ZN-c3, everolimus, and infigratinib) was used to evaluate the impact of 3% IN NEO100 on the brain penetration profile of the three individual drugs. Athymic mice were grouped into four cohorts to receive 1) oral ZEI; 2) IN ZEI; 3) oral ZEI with IN NEO100; and 4) IN ZEI with IN NEO100. At 2, 4 and 6 hours post ZEI dosing, drug levels in plasma and brain tissue were measured by liquid chromatography tandem mass spectrometry (LC-MS/MS). For BBB disruption study, athymic mice were treated with IN delivery of saline (negative control) or 3% NEO100 one hour post intravenous Evans blue (2%) administration. Tumor bearing mice with disrupted BBB served as positive control. Two hours post Evans blue administration, animals were perfused, and brains were collected and sectioned for confocal microscopy to image Evan’s blue autofluorescence. Results: PK analysis revealed that brain-to-plasma ratios (Kp) for ZN-c3, everolimus, and infigratinib remained nearly equal, independent of the route of administration, i.e. 0.11, 0.03, and 0.82 vs 0.09, 0.03, and 0.87, for IN vs oral routes, respectively. Administration of the ZEI together with IN NEO100, either through oral or IN routes, resulted in higher drug concentrations, both in the plasma and in the brain. However, while overall drug exposure was increased, Kp values of the drugs were not changed. Confocal imaging of brains from mice treated with 3% IN NEO100 did not show presence of Evans blue autofluorescence while positive control mice with disrupted BBB within the tumor core displayed high Evans blue fluorescence. Conclusions: Co-administration of IN NEO100 with ZN-c3, everolimus, and infigratinib increases their brain and plasma exposure. As a result, no significant increase in brain-to-plasma partition was registered for any of the three drugs tested in this study. IN NEO100-mediated increase in brain drug concentration was independent of BBB disruption Citation Format: Anil Thaghalli Shivanna, Tigran Margaryan, Mariya Stavnichuk, William Knight, Sonam Patel, Elaine Cabrales, An-Chi Tien, Thomas Chen, Nader Sanai, Artak Tovmasyan, Shwetal Mehta. Pharmacokinetics assessment of intranasal NEO100 treatment on blood-brain barrier disruption and brain penetration of drugs in rodent brain [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7163.

Development of extended pharmacokinetic models for propofol based on measured blood and brain concentrations

Propofol’s pharmacokinetics have been extensively studied using human blood samples and applied to target-controlled infusion systems; however, information on its concentration in the brain remains scarce. Therefore, this study aimed to simultaneously measure propofol plasma and brain concentrations in patients who underwent awake craniotomy and establish new pharmacokinetic model. Fifty-seven patients with brain tumors or brain lesions who underwent awake craniotomy were sequentially assigned to model-building and validating groups. Plasma and brain (lobectomy or uncapping margins) samples were collected at five time-points. The concentration of propofol was measured using high-performance liquid chromatography. Population pharmacokinetic analysis was conducted through a nonlinear mixed-effects modeling program using a first-order conditional estimation method with interactions. Propofol’s brain concentrations were higher than its plasma concentrations. The measured brain concentrations were higher than the effect site concentrations using the previous models. Extended models were constructed based on measured concentrations by incorporating the brain/plasma partition coefficient (Kp value). Extended models showed good predictive accuracy for brain concentrations in the validating group. The Kp value functioned as a factor explaining retention in the brain. Our new pharmacokinetic models and Kp value can predict propofol’s brain and plasma concentrations, contributing to safer and more stable anesthesia.

Scada Pada Proses Destilasi Dengan Pengendalian Suhu Menggunakan PID

Controlling temperature is crucial because it is the most significant factor in the distillation process. Temperature instability is a result of manual and traditional control, and several errors may occur. Therefore, the low quality of the product that is produced during the distillation process has an additional effect. In order to effectively control or manage the system, an automatic temperature control system is designed using an electronic controller with a closed system control mode that not only delivers setpoint values but also feedback.The procedure of distillation that is being employed involves combining two different kinds of solutions: water and ethanol, which has a boiling point of 78°C.Thermocouple sensors are used to monitor temperature, and PLCs with PID control are used to process the temperature data that are obtained. For plant supervision, control, and data collecting, a SCADA is necessary. A number of tests have been conducted, including near loops with and without PID that are SCADA-monitored. The temperature stability response is then examined by analyzing the outcomes of multiple tests that have been conducted. Values of Kp = 5188, Ti = 182, and Td = 457 were found by using the Ziegler Nichols method to the temperature control of the distillation equipment. Furthermore, the steady state error was no more than 1% and the overshoot characteristics were only 2.5%, according to the system response graph.. From the Ziegler Nichols PID control parameters, it shows a good system response and produces ethanol distillation results with a concentration of 88%.

Implementation of Induction Motor Speed Control Using a PID Controller

The three-phase induction machine that is used has a constant speed in accordance with the factory capacity without being able to adjust the speed. The inverter is a motor speed control device by changing the frequency value that enters the motor. Setting the frequency value is intended to obtain the desired rotation speed or as needed. But the inverter itself needs to be added with a controller so that the control value of the motor can be adjusted according to the desired needs. PID controller is a controller that is most widely used in the field of control systems in the industrial world. Combining the three PID constants in parallel can cover every disadvantage and strength of each constant so that a good controller is obtained. Based on the results of the experiments that have been carried out, it can be concluded that the speed of the three-phase induction motor can work well. When tested by giving values of Kp = 02, Ki = 0 and Kd = 3.7, it was found that the motor speed response had a Time Constant = 1.5 seconds, Rise time = 2.2 seconds and Settling time = 2.7 seconds.

Simulation of Automatic Speed Control in Motor Vehicles (Cruise Control) Using Simulink PID Controller

An adaptive control system is an advanced method for controlling the speed of a moving motorized vehicle. Using this intelligent control system, the driver can easily control the speed of the car according to his wishes or the prevailing situation. The adaptive control system consists of a sensor attached to a moving vehicle which then registers the speed of the car and provides input to the processing unit. The controller is designed according to the force exerted by the car to drive a certain distance in a certain time. This time, the control uses a PID controller. This method is followed for various tunings of Kp, Ki, and Kd values for the P, PI, PID, and IPD structures for a cruise control system using MATLAB. The PID used in this experiment is intended to control the speed to make it more stable and optimal.

Distribution of parabens and 4-HB in human blood

Human blood has been commonly and routinely analyzed to determine internal human exposure to parabens. However, data on the occurrence of parabens and their common metabolite, p-hydroxybenzoic acid (4-HB), in different human blood matrixes is still limited. In this study, 139 pairs of serum and whole blood samples were collected from Chinese adults, and then analyzed them for 5 parabens and 4-HB. Methylparaben (MeP) and propylparaben (PrP) were consistently the predominant parabens in human serum (mean 2.3 and 2.1 ng/mL, respectively) and whole blood (1.9 and 1.3 ng/mL, respectively). Mean concentrations of 4-HB in human serum and whole blood were 7.7 and 12 ng/mL, respectively. Concentrations of parabens, except benzylparaben (BzP), and 4-HB in human serum were significantly (p < 0.01) correlated with that in whole blood. Distribution pattern of parabens and 4-HB in human blood was evaluated, for the first time, based on their partitioning between human serum and whole blood (Kp). Mean Kp values of parabens, except BzP, increased with the alkyl chain length from 0.83 to 1.6. BzP (mean 1.4) had a comparable mean Kp value to PrP (mean 1.4). Among target analytes, 4-HB had the lowest mean Kp value (0.75). These data are important to select appropriate blood matrixes for conducting human exposure assessment and epidemiological studies on parabens.

Integrating mathematical approaches (IMAS): Novel methodology for predicting dermal absorption rates of chemicals under finite dose conditions.

Quantitative structure permeation relationship (QSPR) models have gained prominence in recent years owing to their capacity to elucidate the influence of physicochemical properties on the dermal absorption of chemicals. These models facilitate the prediction of permeation coefficient (Kp) values, indicating the skin permeability of a chemical under infinite dose conditions. Conversely, obtaining dermal absorption rates (DAs) under finite dose conditions, which are crucial for skin product safety evaluation, remains a challenge when relying solely on Kp predictions from QSPR models. One proposed resolution involves using Kroes' methodology, categorizing DAs based on Kp values; however, refinement becomes necessary owing to discreteness in the obtained values. We previously developed a mathematical model using Kp values obtained from in vitro dermal absorption tests to predict DAs. The present study introduces a new methodology, Integrating Mathematical Approaches (IMAS), which combines QSPR models and our mathematical model to predict DAs for risk assessments without conducting in vitro dermal absorption tests. Regarding 40 chemicals (76.1 ≤ MW ≤ 220; -1.4 ≤ Log Ko/w ≤ 3.1), IMAS showed that 65.0% (26/40) predictions of DA values were accurate to within twofold of the observed values in finite dose experiments. Compared to Kroes' methodology, IMAS notably mitigated overestimation, particularly for hydrophilic chemicals with water solubility exceeding 57.0 mg/cm3. These findings highlight the value of IMAS as a tool for skin product risk assessments, particularly for hydrophilic compounds.

Modeling study of boiler using oil waste as an energy source

Used oil waste is one type of waste that can be used as a source of energy. Waste oil that is used in this research is used as energy source for plasma burner and boiler plants. This final project is aimed at modeling a boiler with 3 input variables and 3 output variables (MIMO - Multiple Input Multiple Output). It's known that this MIMO system still exhibits interactions among the variables. To mitigate these interactions, a decoupler is designed. Subsequently, PID controllers are designed for this MIMO system. The PID parameter values are obtained through modeling using the Ziegler-Nichols method. The modeling is carried out based on the values obtained from the Ziegler-Nichols calculations, which are then implemented in Simulink within MATLAB. The test results indicate that employing a decoupler reduces the interactions between the systems. Therefore, Ziegler-Nichols and heuristic method is needed to find the PID parameter values. By utilizing the heuristic method, the system achieves stability with the value of Kp = 2,1, Ki = 0,005, dan Kd = 0 for the first variable, Kp = 0,0315 Ki = 0, dan Kd = 0 for the second variable, and Kp = 0,007 Ki = 0, dan Kd = 0 for the third variable..

Al and Mo synergistic enhancement of CoCrFeNi high-entropy alloy laser cladding layer

A CoCrFeNi high-entropy alloy (HEA) coating, enhanced with Al and Mo, was fabricated on Q235 steel using laser cladding technology. The synergistic enhancement effect of Al and Mo on the coatings was studied. The findings revealed that the CoCrFeNi coating mainly comprised the single-phase FCC. In contrast, the BCC and σ phases were observed when Al and Mo were individually doped. The simultaneous doping of both these elements resulted in a coating consisting of the BCC and σ phases. Mo addition led to grain refinement and increased the kernel average misorientation value; similarly, Al addition further enhanced these effects. The separate additions of Al and Mo significantly refined the microhardness and wear resistance of the coating. When both elements were added simultaneously, the microhardness and wear resistance of the coating were further enhanced, demonstrating the synergistic effects of Al and Mo on these characteristics. Moreover, the individual doping of Al and Mo decreased the Kp value and the oxide layer's thickness. Meanwhile, their combined addition reduced the Kp value by approximately 82.5 % and 89.8 %, respectively. During the initial oxidation stage, rapid oxidation of Al occurred, thereby decreasing the oxidation rate. In contrast, Mo facilitated the formation of Al2O3.

Performance analysis of proportional feedback control and integral control in DC motors and speed control

Control systems play a crucial role in modern engineering and technology, and their stability and performance are vital for the success of various applications. This paper aims to explore the application and performance analysis of proportional feedback control (P control) in DC motors and integral control (PI control) in speed control. The following section provides an exposition of the fundamental principles underpinning P control and PI control, alongside an exhaustive account of their practical implementations within the Tinkercad and Octave software environments. The simulations carried out in Tinkercad serve as the basis for evaluating step responses associated with varying values, leveraging a 1Hz function generator. Subsequent analysis pertains to proportional-integral control through the utilization of Octave's PZmap and root locus methodologies, with specific regard to their implications for system stability and control performance in the context of speed control. The experimental outcomes reveal the aptitude of P control in scenarios demanding rapid responses, while establishing the superiority of PI control in the context of steady-state error mitigation. In the experimental analysis conducted, an evident trend emerged as Kp values were systematically increased within the framework of proportional feedback control. The primary observation related to the reduction in system response times, along with the concurrent rise in overshooting tendencies.

Morphology, phase composition, surface roughness evolution and growth mechanism of hot-dip aluminum coating on Mo substrate

The Al-rich hot-dip aluminum composite coatings were synthesized on Mo surface by hot-dip aluminizing under different deposition processes. The aluminide coatings present a very smooth dense coating structure with a lower surface roughness and fine grain size, the average surface roughness (RSa) values are only 0.118–0.869 μm, and the corresponding surface area growth rate (Sdr) values are 3.85–80.19 %. Increasing the deposition temperature is beneficial for the transition of low melting point compounds of the coating surface to high melting point compounds, and extending the hot dip time is profit for the diffusion and enrichment of Al atoms on the coating surface. Besides, increasing the deposition temperature or time can also promote the growth of Al4Mo grains, thereby significantly increasing the coating thickness. When the deposition temperature is 750 °C, the thicknesses of Al4Mo and Al8Mo3 layers increases in a parabolic law with deposition time, and the Kp values both of them are 3.46 × 10−13 m2/s and 1.47 × 10−15 m2/s, respectively. The growth of the coating depends on the continuous diffusion of Al atoms towards the substrate direction, and the difference in chemical potential between Al atoms in each phase is the main driving force for coating growth.

First-Principles study of the structural, electronic, elastic, lattice dynamics and thermoelectric properties of the newly predicted half-heusler alloys NaYZ (Z = Si, Ge, Sn)

In this study, we applied Density Functional Theory (DFT) and Boltzmann Transport Theory to investigate the structural, electronic, lattice dynamic, elastic and thermometric properties of new half-Heusler compounds NaYZ (Z = Si, Ge, Sn). The structural optimization calculations revealed that the ZXY (1/4,1/2,0) phase have the most stable state with the least energy among others. Our calculated lattice constants in (Å) are found to be 6.861, 6.899, and 7.284 for NaYZ (Z = Si, Ge, Sn). Also, the calculated elastic constants satisfied the Born-Huang criteria and were found to be mechanically and elastically stable. The Density Functional Perturbation Theory (DFPT) was used to examined the lattice dynamics of the compounds and the results shown non-existence of negative frequencies all through dispersion band structures, thus all the compounds are dynamically stable. The Seebeck coefficient of the compounds at room temperature for the p-type (n-type) are 143.79 (−48.91) μ V/K, 132.49 (−48.86) μ V/K, 154.75 (−60.24) μ V/k for NaYZ (Z = Si, Ge, Sn). The modified Slack's approach was used to compute lattice thermal conductivity (kp) within the experimental range and the kp values obtained for NaYZ (Z = Si, Ge, Sn) at room temperature are 17.265 Wm −1 K −1, 14.671 W m−1K−1, 10.693 W m−1K−1, respectively. The computations of charge carriers relaxation time (τ = F(T)) as a function of temperature through deformation potential theory and the effective mass of charge carriers were used to evaluate the figure of merit (zT) for p-type and n-type of the materials. The maximum zT at 1200 K of τ = F(T) (τ = 10−13 s) are 1.76 (1.67), 1.73 (1.65), and 1.91 (1.88). These results show that τ = F(T) has improvement in determining the figure of merit as compared to the constant relaxation time (τ).

Speed control of direct current motors using proportional integral controllers

Proportional integral(PI) controllers is widely used in direct current(DC) motor controlling in factories, requiring tuning of their parameters to achieve optimal performance. New tuning techniques may be developed with the aid of research, which can speed up and simplify the tuning process. This work examined the use of PI controllers to regulate the speed of DC motors. TinkerCad modelling and Falstad circuit simulation are used to simulate the circuit model. Two well-known methods, step response and root locus, were implemented and assessed using Octave Online. Results demonstrate that, provided the KP value is not excessively high, increasing KP can enhance the stability of the DC motor close-loop system. The goal of the research is to balance the system's oscillation and stability while determining the appropriate KP value for the PI controller in this closed-loop system. This research uses octave online to analysis the root locus and close loop positions in pole-zero maps and creates the step responses of the system with different parameters of the PI controller.