Values Of Kt Research Articles

INTERACTION ANALYSIS HULL AND PROPELLER AND IMPROVEMENT OF EFFICIENCY PROPELLER ON FISHING VESSELS

The determination of propeller and hull adjustment of both small and large fishing vessels is indeed very important, in general, fishing vessels at the port of Lamongan only use hereditary techniques. many weaknesses in the problem of synchronization between the hull, the main propulsion engine, and the propeller. therefore, after analysis, it can be concluded, that at the coastal port of Lamongan, an Ijon-Ijon type fishing boat, with a main size of 5-10 GT. In one ship using the Mitsubishi Fuso 120 ps 2 engine type, using 2 gearbox advance ratio 3.1 rated input speed 1000- 2500 r/min and rated trans capacity 0.039 kW/min with a total resistance value of 17.599 kn, wake fraction value 0.235, value thrust deduction 0.197 and using a propeller with type B-series B3-35 with a diameter of 1.54 with a KT value of 0.31, a value of 10KQ 0.37, a value of J 0.52 and an average efficiency value of 0.48. By changing the diameter propeller to 1.75 and changing the ratio gearbox with the same engine, a comparison can be made between the efficiency of the propeller previous and the efficiency after changing the diameter propeller with a KT value of 0.30, a value of 10KQ 0.345, a value of J 0.55 and average efficiency value 0.565.

Dielectric anomalies and dc-resistivity degradation in PbNb2O6-based ceramics at high temperature

The lead metaniobate (PbNb2O6, PN) with high Curie temperature is widely used to fabricate transducer for high-temperature application up to 300 °C. However, evident dielectric anomalies and direct-current resistivity degradation were experimentally observed in PN-based ceramics at high temperature, which may significantly restrict the working temperature range for well logging application. When the sample was heat-treated at 260 °C for 3 h in silicon oil, the dc-resistivity of ceramics at 260 °C decreased from 3.8 × 108 to 1.0×107 Ω⋅cm, accompanied by 43 times increase in tanδ at 1 kHz. To investigate the cause of these phenomena, the in-situ piezoelectric, dielectric properties and dc-resistivity were systematically investigated in the samples subjected to heat-treatment at 260 °C in silicon oil. It is revealed that the porous structure of PN-based ceramics allows for the infiltration of silicon oil as a minor phase, and the accumulation of its decomposers within the pores would exert significant influence on the dielectric property and dc-resistivity of ceramics at elevated temperatures. However, the samples still demonstrate excellent thermal stability in piezoelectric property, with value of kt maintaining 0.39 at 260 °C in oil. In addition, the low Qm is not the intrinsic property of PN ceramics, but rather related to the phase transition of silicon oil within pores of ceramics, as indicated by the increase in Qm from 47 to 80 after heat-treatment in air.

Seasonal Variations in Hydraulic Regulation of Whole-Tree Transpiration in Mongolian Pine Plantations: Insights from Semiarid Deserts in Northern China

Seasonal precipitation variance significantly alters soil water content, potentially inducing water stress and affecting plant transpiration in semiarid deserts. This study explored the effects of environmental variables and hydraulic conductance on whole-tree transpiration (ET) in Mongolian pines (Pinus sylvestris var. mongolica) across different forest stages in the semiarid deserts of Northern China. We measured ET using sap flow in mature (MMP), half-mature (HMP), and young (YMP) Mongolian pine plantations. Measurements included soil-leaf water potential difference (ΔΨ), atmospheric conditions, and soil moisture contents on sunny days, both in dry and wet periods. Seasonally variable rainfall distinctly affected soil moisture; during the dry periods, both stomatal and hydraulic conductance influenced ET, whereas stomatal conductance primarily regulated it during the wet periods. Discrepancies between predicted and measured ET were noticed: compared to the predicted ET, the measured ET was lower during dry periods while higher during wet periods. Hydraulic conductance (KT) increased with tree height (H) and ΔΨ. The KT values in the dry period were lower than those in the wet period, indicating that the hydraulic resistance in the dry period was higher. The hydraulic compensation occurred and was observed between 11:00 and 13:00, aligned with increased hydraulic resistance during dry periods. Decreasing hydraulic conductance intensified leaf water stress in dry periods, especially when photosynthetically active radiation (PAR) and vapor pressure deficit (VPD) were heightened, potentially increasing stomatal sensitivity to drought, promoting water conservation and plant survival. A linear relationship between predawn and midday leaf water potentials was noticed, indicating extreme anisohydric behavior across forest stages during dry and wet periods. Although stomatal and hydraulic conductance influenced ET during the dry period, MMP and YMP were more susceptible to drought conditions. Understanding these dynamics could help evaluate semiarid desert ecological functions for water conservation amidst uneven seasonal precipitation in Northern China.

Tensile behavior of a novel self-locking inter-module connection in modular steel buildings

Modular steel buildings (MSBs) consist of complete steel modules and inter-module connections; the latter plays a crucial role in assembly efficacy on-site and in resisting the tension load at the base of a high-rise modular building subjected to lateral loads. This paper investigates the tensile performance of the proposed self-locking inter-module connection. Two full-scale experiments were conducted to evaluate the axial tensile behavior of this innovative connection. The mechanical properties of the self-locking inter-module connection were obtained and analyzed, including the failure modes, ultimate bearing capacity, and strain distribution. Under axial tension load, the self-locking inter-module connection exhibited adequate load-carrying capacity and ductility, as evidenced by the results. The refined finite element (FE) model of the self-locking inter-module connection was developed and validated against experimental data. Then, FE modeling was used to further investigate the working mechanism of the self-locking inter-module connection under axial tensile force. Two essential parameters were considered, including the bottom plate thickness of the upper corner fitting and the top plate thickness of the lower tenon. The numerical results demonstrated that the failure mode of such a self-locking inter-module connection was dependent on the relative relationship of the aforementioned two key parameters, which is reflected by the ratio (Kt) of the vertical shear area of the bottom plate of the upper corner fitting and the top plate of the lower tenon. Considering tensile resistances and material strength utilization, a range of values for the parameter Kt and design recommendations were provided.

Translucency of chairside monolithic zirconias using different sintering ovens: An in vitro investigation

ObjectiveTo evaluate the translucency of several monolithic zirconias (MZ) processed in various sintering ovens designed for single-visit, chairside use. MethodsDiscs (n = 40) from zirconia blocks were fabricated for each MZ at manufacturer-recommended minimal thicknesses, as provided in each material's instructions for use: IPS e.max ZirCAD LT (ZLT); CEREC Zirconia+ (CZ+); 3M Chairside (3M); KATANA Zirconia (KT). Groups (n = 10) were sintered following manufacturer instructions for each oven: CEREC SpeedFire, Ivoclar CS4, Ivoclar CS6, and Ivoclar S2 (laboratory furnace control). Specimens were highly polished on one side and glazed on the other. Each side was measured with a spectrophotometer against white and black backgrounds to determine translucency parameter (TP) and contrast ratio (CR) values. Results for TP and CR for each material and oven combination were compared with a linear mixed model. Oven precision was evaluated using the Kruskall-Wallis test. ResultsGlazed specimens were more translucent than polished ones (p < 0.001). ZLT and CZ+ were more translucent than 3M and KT regardless of the sintering oven (p < 0.01). Several oven/material combinations reached or exceeded the S2 oven TP: CS4 with CZ+ and 3M; CS6 with ZLT and KT (p < 0.01). SpeedFire was significantly less precise (p < 0.05) and produced lower TP values for ZLT, CZ+, and KT (p < 0.01). Results for TP and CR were highly correlated. ConclusionsMZ surface finish, material thickness, and oven used all had a significant effect on translucency. Some chairside-oriented solutions produced results with translucency equal to conventionally processed zirconia. Clinical significanceThe translucency of a ceramic restoration is an important factor in determining its esthetics. Clinicians desiring the most esthetic outcomes with monolithic zirconia should be aware of the significant effects that surface finishing, material thickness, and the sintering oven used can have on restoration translucency.

The role of corrosion pit topography on stress concentration

Smooth semi-ellipsoids are typically used to simulate the effect of corrosion pits on stress, however, this does not account for pit geometry. Three corrosion pits were identified on Nickel Aluminium Bronze samples. These were scanned and converted to finite element models. The linear elastic stress concentration factor (Kt) of the corrosion pit FE models was 1.32–1.65 times larger than for an equivalent smooth semi-ellipsoid. This suggests that detailed consideration of pit geometry is needed to calculate accurate values of Kt and the assumption of a semi-ellipsoidal pit may not be conservative for fatigue lifetime predictions of pitted components.

Novel Method for the Arsenic Removal Experiment and Mechanism Analysis.

This study focuses on the hydrothermal synthesis of magnetically activated carbon and its efficacy in As(III) adsorption. The successful incorporation of magnetite nanoparticles within the porous carbon structure was confirmed, enriching the adsorbent's properties. Comprehensive characterization was performed to analyze the pore size distribution, zeta potential at varying pH levels, and thermostability using thermogravimetric analysis. These adsorbents exhibited high As(III) removal efficiency with a uniform pore distribution. The zeta potentials were observed to decrease with an increase in pH, suggesting a relationship between adsorbent charge and pH. Adsorption dynamics were rigorously modeled using pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models for different adsorbents labeled as a,b,c, and d. Each adsorbent displayed unique fitted parameters, revealing varied adsorption capabilities. The study further explored the adsorption kinetics and found that the pseudo-second-order kinetics model and the Langmuir model were most appropriate for describing the adsorption process. Adsorption thermodynamics was also fitted to elucidate the underlying adsorption mechanisms. For the a,b,c, and d adsorbents, the pseudo-first-order model, the qe(cal) values for the four adsorbents were 434.2, 418.4, 283.5, and 279.5 μg/g, respectively. Take adsorbent a as an example; the qm values for 298, 303, 308, and 313 K were 702, 673, 605, and 589 μg/g, respectively, and KL values of these temperatures were 0.021, 0.031, 0.018, and 0.009 L/μg, respectively. For the Langmuir model, the R2 values at the four temperatures were 0.999, 0.978, 0.985, and 0.993, respectively, which indicated that the Langmuir model showed higher fitness. For the Freundlich model, the KL values (L/μg) at the parameters of these temperatures are 432, 409, 328, and 294, respectively. For the Freundlich model, the 1/n values at temperatures of 298, 303, 308, and 313 K are 0.049, 0.045, 0.052, and 0.035, respectively. For the Freundlich model, the R2 values at parameters of 298, 303, 308, and 313 K are 0.986, 0.989, 0.982, and 0.872, respectively. For the Temkin model, the B values (in J/mol) are 30.93, 0.894, 0.824, and 0.782 at these temperatures, respectively. The KT values (in L/μg) are 1.02 × 106, 0.07 × 106, 0.003 × 106, and 0.002 × 106, respectively. The R2 values are 0.973, 0.958, 0.972, and 0.894, respectively. In the end, the ΔH, ΔS, and ΔG values for different adsorbents were calculated. Collectively, these findings contribute significant insights into the design and application of magnetically activated carbon adsorbents for effective As(III) removal.

Numerical and Experimental Investigations into the Characteristics of Wageningen B4-70 Series of Propeller with Boss Cap Fins

Applying propeller boss cap fins (PBCF) in open B-series has been studied. PBCF is able to decrease the wake effect behind the propeller which can influence the propeller’s thrust and torque. Open propeller using PBCF is analyzed using computational fluid dynamics (CFD) which generate convergent result compared to experimental data. The solver is based on the Reynolds Averaged Navier Stokes Equation (RANSE) solutions and turbulence modeling explicit algebraic stress model (EASM). The test data was obtained from CFD simulations consisting of the open propeller and PBCF despite the experiment was done to PBCF only. All measurements were carried out from J = 0 to J = 1.0 with speeds from 0 m/s to 2.445 m/s.The results of the investigation on the B4-70 propeller with Boss cap fins convergent showed thought-provoking phenomena both on CFD and experimental work. Test results at The B4-70 Propeller without using PBCF high Pressure at J = 0.1 - 0.9, but with boss cap fins can reduce pressure at high-speed J = 0.9, so further research is needed to low-speed J = 0.1 - 0.5; Then visualization of velocity on propeller B4-70 without PBCF shows an increase in flow velocity in the boss cap fins when J = 0 to J = 0.9. The induced axial velocity in the blade propeller is the same and propeller B4-70 with PBCF decreases in speed in the boss cap fins when J = 0 to J = 0.9. However, the induce axial velocity in the blade propeller is the same. Convergent PBCF can reduce the return flow velocity in the boss cap propeller area, inversely proportional to the open propeller. Comparison of open propeller and PBCF shows that using PBCF there is an increase in the KT value at high speed of 10% to24% and a decrease in the 10KQ value on PBCF from J = 0.8 to J = 1.0 of 7% to 14%, but η_0 value at J = 0.8 to J = 1.0 increased by 3% to 8%. This Explained that the use of PBCF when the higher the value of J, greater the increase in η_0 value. Mainly, B4-70 propeller with PBCF with a converging boss cap shape with 15-degree slope exhibits increased efficiency.

Large Uncertainties in CO2 Water–Air Outgassing Estimation with Gas Exchange Coefficient KT for a Large Lowland River

Aquatic CO2 emission is typically estimated (i.e., not measured) through a gas exchange balance. Several factors can affect the estimation, primarily flow velocity and wind speed, which can influence a key parameter, the gas exchange coefficient KT in the balancing approach. However, our knowledge of the uncertainty of predictions using these factors is rather limited. In this study, we conducted a numeric assessment on the impact of river flow velocity and wind speed on KT and the consequent CO2 emission rate. As a case study, we utilized 3-year (2019–2021) measurements on the partial pressure of dissolved carbon dioxide (pCO2) in one of the world’s largest alluvial rivers, the lower Mississippi River, to determine the difference in CO2 emission rate estimated through three approaches: velocity-based KT, wind-based KT, and a constant KT (i.e., KT = 4.3 m/day) that has been used for large rivers. Over the 3-year study period, river flow velocity varied from 0.75 ms−1 to 1.8 ms−1, and wind speed above the water surface fluctuated from 0 ms−1 to nearly 5 ms−1. Correspondingly, we obtained a velocity-based KT value of 7.80–22.11 m/day and a wind-speed-based KT of 0.77–8.40 m/day. Because of the wide variation in KT values, the estimation of CO2 emission using different approaches resulted in a substantially large difference. The velocity-based KT method yielded an average CO2 emission rate (FCO2) of 44.36 mmol m−2 h−1 for the lower Mississippi River over the 3-year study period, varying from 6.8 to 280 mmol m−2 h−1. In contrast, the wind-based KT method rendered an average FCO2 of 10.05 mmol m−2 h−1 with a small range of fluctuation (1.32–53.40 mmol m−2 h−1,), and the commonly used constant KT method produced an average FCO2 of 11.64 mmol m−2 h−1, also in a small range of fluctuation (2.42–56.87 mmol m−2 h−1). Based on the findings, we conclude that the effect of river channel geometry and flow velocity on CO2 outgassing is still largely underestimated, and the current estimation of global river CO2 emission may bear large uncertainty due to limited spatial coverage of flow conditions and the associated gas exchange variation.

A Numerical Study of the Damage Mechanisms for CT Tensile Specimens of P265GH Steel Material

The aim of this paper is to determine the damage mechanisms of P265GH steel, commonly used for pressure equipment. First, an experimental study using tensile and Charpy tests allowed us to determine the mechanical properties (Young modulus E = 200 GPa, elongation ε = 35%, yield se = 320 MPa, ultimate stress su = 470 MPa, and KIC = 96 MP√m). Then, numerical finite element modeling on a CT specimen using the CASTEM calculation code allowed us to determine the damage of the material when the notch depth varies. The analysis of the results shows that the numerical values of the stress concentration coefficient Kt and the stress intensity factor KI are comparable with the analytically calculated values, thus validating our numerical study. The numerical results obtained revealed that the maximum stress σmax is located in the vicinity of the notch bottom and the high probability density corresponds to a high loading level.

Temporal Variability of Solar Energy Availability in the Conditions of the Southern Region of Mozambique

The use of photovoltaic solar energy is affected by variations in the availability of solar radiation, which creates stability in solar panels. In our case, the need arose to study the temporal variability of solar energy in the southern region of Mozambique. This was followed by a descriptive sequence, applying the analytical method for the classification of days and the analysis of the day’s variability of clear, cloudy and intermediate skies in the data from three regional stations. The results show that it was mostly on clear sky days (44.64%), enhancing the use of solar energy. Statistical analysis of the frequency density variability shows that days with intermediate skies have a similar behavior, however they present a smooth decrease, because for variation of clear sky index ∆Kt* in the interval [-2,2] it is higher. The values of Kt* vary between 0.3342–1.2764, the minimum is observed in the month of July and the maximum in December and the variations during the daily course of the Kt* determined according to its standard deviation show such suitability to the model adopted for the calculation of global irradiation under the clear sky, as an appropriate choice of time interval and amplitude for the study of variations.

Evaluation of the results of treatment of patients with functional dysphonia using a cepstral test

In order to evaluate the effectiveness of the treatment in patients with functional dysphonia, the Cepstral Peak Prominence (CPP) test was used. Twenty dysphonic women aged from 18 to 47 years were under observation. The control group consisted of 20 healthy women of close age. Patients underwent 5-7 sessions electrostimulation of laryngeal muscles and phonopedic treatment, after which a complete restoration of the voice was noted. The Praat clinical program was used, installed on a Hewlett-Packard 630 laptop (Pentium B960, 2.2 GHz). A SHURE SM94 condenser microphone was used as well. In the control group, the results were as follows: M=7.49 (SD=1.26) dB. In the main group before treatment: M=5.00 (SD=1.07) dB, after treatment: M=7.95 (SD=1.34) dB. Differences in KT values in the main group before and after treatment (5.00 dB and 7.95 dB, respectively) were significant at p<0.0001. Differences in KT values in the main group before treatment (5.00 dB) and in the control group (7.49 dB) were significant at p<0.0001. Differences in KT values in the main group after treatment (7.95 dB) and in the control group (7.49 dB) were not significant at p>0.05. The study showed high sensitivity of the method. The CPP data after treatment were higher than those before treatment and did not differ from the control ones. It is concluded that CPP is a highly sensitive method for evaluating the degree of periodicity of an acoustic signal and can be used to evaluate the effectiveness of treatment in patients with functional dysphonia.

Transfer Parameter Analysis of Chloride Ingress into Concrete Based on Long-Term Exposure Tests in China’s Coastal Region

Chloride penetration resistance is one of the most important performance measures for the evaluation of the durability of concrete under a chloride environment. Due to differences in theory and experimental conditions, the durability index (chloride diffusion coefficient) obtained from laboratory accelerated migration tests cannot reflect the real process of chloride ingress into concrete in the natural environment. The difference in test methods must be considered and the transfer parameter kt should be introduced into the service life prediction model when the test results of accelerated methods are used. According to the test data of coastal exposure in South China, the attenuation rule of the chloride diffusion coefficient of different cement-based materials changed with time and was analyzed in this paper. Based on the diffusion coefficient-time curve, the theoretical natural diffusion coefficients of 28 d and 56 d were deduced, which were compared with the chloride diffusion coefficients obtained from the non-steady-state rapid migration method (RCM) at the same age. Therefore, the transfer parameter kt that expounds the relationship between concrete resistance to chloride permeability under a non-stationary electrical accelerated state and natural diffusion in the marine environment can be calculated; thus, the RCM testing index can be used to evaluate the long-term performance of the concrete structure in the marine environment. The results show that the value of kt was related to environmental conditions, test methods, and binder systems.

Stress Concentration Analysis of the Corroded Steel Plate Strengthened with Carbon Fiber Reinforced Polymer (CFRP) Plates

The purpose of this study is to investigate the stress concentration of a corroded steel plate strengthened with carbon fiber reinforced polymer (CFRP) plates. An accelerated corrosion experiment was first executed to acquire corroded steel plates, and then surface profile measurements were conducted to obtain 3D coordinate data of the corroded steel surface. Finite element models considering the surface morphology of the corroded steel plate and the interfacial bonding properties between the CFRP plate and the corroded steel plate were established to investigate the stress concentration of the corroded steel plate strengthened with and without CFRP plates. The reliability of the numerical modeling method was verified based on a mesh convergence analysis and a comparison of the fatigue test, 3D morphology scanning, and numerical analysis results. Specimens with five levels of corrosion damage, six kinds of CFRP-strengthening stiffness, five kinds of adhesive thickness, and five levels of CFRP prestress were numerically modeled. The primary indications consist of features of stress distribution, and the stress concentration factors Kt and Ktg were analyzed. Results showed that the features of stress distribution and the stress concentration factor Kt of the corroded steel plate strengthened with and without CFRP plates are only related to the shape, size, and position of rust pits, but not to the degree of uniform corrosion or the reinforcement parameters. The value of Kt for the corroded steel plate with a corrosion duration of 6~18 months and a weight loss rate of 9.16~21.78% was approximately 1.199~1.345. The converted stress concentration factor Ktg has more practical significance than the stress concentration factor Kt in describing the influence of corrosion and CFRP reinforcement on the peak tensile stress of the corroded steel plate. The value of Ktg increased linearly with the increase of the weight loss rate of the corroded steel plate and decreased appreciably with the increase of the strengthening stiffness and prestress level of the CFRP plates, and it presented a very small increasing trend with the increase of the adhesive thickness.

The values of ΔfHo298.15 and So298.15 of the radicals formed by the abstraction of H atom from the p‐Benzylphenol and Dimethyl Phthalate

AbstractIn the present work, the thermochemical properties of the radicals (Yj), formed by abstraction of H atom from Dimethyl Phthalate (o‐Ph(C(O)OCH3)2) and p‐Benzylphenol (p‐PhCH2PhOH), are determined at the B3LYP/6‐311++G(d,p) (j = 1), M06‐2X/6‐311++G(d,p) (j = 2), and RO/CBS‐4 M (j = 3 and 4) levels of theory. Their calculated values of Ho298.15(Yj, CALC) are used for the determination of thermochemistry of atomization (ΔrHo298.15(Yj,CALC)atom) and homodesmotic (ΔrHo298.15((RYi)j,CALC)REAC) reactions of considered radicals. The reported calibration dependencies are used for the correction of calculated values and determination of the most consistent and accurate values of ΔfHo298.15 and ΔfGo298.15. It is found that o‐CH3OC(O)PhC(O)OCH2∙ (1C), p‐PhC∙HPhOH (1D) and p‐PhCH2PhO∙ (3D) are the most thermochemically stable structures. The intersection of reported 3SEj (= 3σj) intervals of ΔfHo298.15(1Cj,CORR)atom of atomization results the value of ΔfHo298.15(1C,CORR)MEAN = −405.1 ± 1.3 kJ/mol (±3SEY = 3σY), while, the most accurate values of ΔfHo298.15(1D and 3D,CORR)REACMEAN = 114.7 ± 0.4 and 135.8 ± 5 kJ/mol (± 3SEYREAC = 3σYREAC) are determined using the values ΔfHo298.15((RYi)j,CORR)REAC of homodesmotic reactions. The values of ΔfGo298.15, determined using the values of ΔfHo298.15 and So298.15 of these radicals, demonstrate that the exothermic reaction (17) HO2∙ + p‐PhCH2PhOH → H2O2 + p‐PhC∙HPhOH (–22.9 kJ/mol) is thermochemically more favorable than the reaction (19) HO2∙ + p‐PhCH2PhOH → H2O2 + p‐PhCH2PhO∙ (–1.8 kJ/mol). However, the value of kT(17) = 1.63 × 10–14(T/298.15)3.6e(‐6282/T), calculated using the VTST, is kinetically more favorable at elevated temperatures, while, the reaction (19) (kT(19) = 1.04×10–16(T/298.15)2.17e(–5207/T)) is more important at T &lt; 200 K. The thermochemical properties of these radicals, as well as the calculated rate constants of their formation in reactions of HO2∙ radicals with p‐Benzylphenol, are reported for the first time.

Study of Global Solar Radiation in Duhok Province

This paper studies and analyzes the ground-based global solar radiation (GSR) data available in the Dohuk governorate. The data was collected from the Meteorological Directorate in Duhok for six stations: Kani Masi, Bamarni, Amedi, Mangesh, Akre, and Semel.&#x0D; The highest monthly average values of GSR in Duhok were in June and July, and the lowest values were in December and January. Among all stations, Amedi has the highest value of the monthly mean of GSR (8.7041 kWh/m2/day) followed by Kani Masi at (8.5265), Mangesh at (8.3249), Bamarni at (8.072), Semel (7.0506) and finally Akre 6.1171(kWh/m2/day), while the lowest values of GSR were in December 2018 mostly, except for Semel was in December 2016.&#x0D; The annual mean of GSR in (kWh/m2/day) for these stations were 5.0168, 4.8311, 4.817, 4.7546, 4.3155, and 3.6183 for Amedi, Kani Masi, Mangesh, Bamarni, Semel, and Akre respectively.&#x0D; The monthly mean of the daily clearness index of the study area peaks is in the mid months of the year (May, June, July, August, and September). KT values experienced a dramatic decrease in March in all stations except Mangesh showed a slight increase. Among all the stations, Akre saw the lowest values in KT ranging from 0.32997 to 0.50686 with an annual average of 0.42443.

In situ axial loading tests on H-shaped steel strut with double splay supports

The design of a large excavation using a braced wall system (BWS) with H-shaped steel (HS) struts is introduced. In situ axial loading tests were conducted to study the load transfer and deformation mechanisms of an HS strut with double splay supports. The monitoring results indicate that the outer splay support withstands the most lateral earth pressure (48.5%), followed by the inner splay support (35.6%) and BC segment of the end support (15.9%). The safety redundancies of strength and stability for the outer and inner splay supports, AB and BC segments of the end support are all larger than 1.59. The axial deformations of the middle support and the whole strut tend to increase linearly with the loading process. Using the monitored total load of hydraulic jacks, the value of KT″ of the whole strut is estimated to be 158–189 MN/m. The modified value of KT″ (KT″ba/S) of the whole strut is 2.2–2.6 MN/m. It is close to the lower limit of the suggested range (2.5–3.5 MN/m) in the Chinese standard. The monitored data of typical safety control parameters during soil excavation and the monitored results during in situ loading tests indicate good performance of the BWS with HS struts in this project.

Equilibrium Composition of Products Formed by Non-catalytic Conversion of Hydrocarbons

The kinetic patterns of the attainment of the equilibrium product composition in non-catalytic processes of partial oxidation and of steam and carbon dioxide reforming of hydrocarbons in the temperature range 1400–1800 K, characteristic of these processes, were analyzed. The need for such analysis is caused by the rapidly increasing consumption of natural gas as a chemical feedstock and by growing attention to environmental problems, in particular, to a decrease in СО2 emissions or to partial CO2 utilization. The forward and reverse water gas shift reactions (WGSRs) play an important role in approach to the equilibrium product composition in these processes. Analysis has shown that the elementary reactions characteristic of forward and reverse WGSRs start to play a significant role long before the equilibrium in the system is attained. Already in the intermediate steps of the process, the distribution of the major reaction products, Н2, СО, Н2О, and СО2, almost corresponds to the equilibrium value of Kt = ([H2][CO2])/([CO][H2O]), close to the WGSR equilibrium constant Keq, and further conversion of the products occurs at Kt values close to Keq.

Stress Concentration Factors in Excavation Repairs of Surface Defects in Forgings and Castings.

This paper provides an analytical formula for the theoretical stress concentration factor in a common type of excavation repair for large forgings and castings. Mechanical components obtained with these processes are often subjected to superficial defects. As the rejection of such pieces is out of question, given the relevant size and costs associated with them, usual industrial practice consists in the removal of the defect and a portion of the surrounding material through milling processes. The authors have selected a reference geometry of the excavation to be left on the mechanical pieces, which can be easily controllable in practice by three operating parameters. Then, the domain of existence of such a repair was investigated on a sequence of discrete points, by means of FEA, obtaining for each, the values of the stress concentration factor Kt. Finally, through polynomial regression, the Kt functions have been accurately approximated by a sixth degree polynomial formulation, which, given a triplet of dimensional geometric parameters, is able to compute the stress concentration factor Kt, with an error that never exceeds 8%.

Validation of the SMH Equations for the Estimation of the Total Body Water Volume in Hemodialysis Patients.

Online dialysis clearance monitors typically provide an accurate value for Kt. A value for V (total body water [TBW]) is required to calculate Kt/V, the measure of the adequacy of the delivered dialysis in hemodialysis (HD) patients. Using bioimpedance spectroscopy (BIS), we previously developed 2 sex-specific equations for the estimation of the TBW, which we have chosen to name the St Michael's Hospital (SMH) equations. The objective of this study was to validate the SMH equations in a second distinct population of patients. Cross-sectional study. Single center hemodialysis unit at St Michael's Hospital, a tertiary care teaching hospital, in Toronto, Canada. Eighty-one adult HD patients who had been receiving conventional maintenance HD for at least 3 months. Anthropometric measurements including weight, height, and waist circumference were collected. TBW was measured by BIS using the Body Composition Monitor (Fresenius Medical Care, Bad Homburg, Germany). The Bland-Altman method to calculate the bias and limits of agreement and the difference plot analysis were used to evaluate the difference between the BIS-TBW and the TBW derived from our equations (SMH equation) in this validation cohort. The TBW values based on our equations had a high correlation with BIS-TBW (correlation coefficients = 0.93, P values < .01, bias = 1.8 [95% CI: 1-2.6] liter). Application of SMH equations closely predicted Kt/V, based on BIS value, in all categories of waist circumference. Small sample size, single-center, not including peritoneal dialysis patients. A larger and more heterogeneous sample with more patients at the extremes of body mass index would allow for more detailed sub-group analyses in different races and different anthropometric categories to better understand the performance of these equations in discrete sub-groups of patients. In maintenance HD patients, our previously derived equations to estimate the TBW using weight and waist circumference appear to be valid in a distinct patient population. Given the centrality of TBW to the calculation of small molecule clearance, the SMH equations may enhance the measurement of dialysis adequacy and inform practice.