Formula For Rate Research Articles

Determining control in production suction vessels (KIP) 16 Bangka Ocean mining units PT Timah (Persero) Tbk

This research discusses the control of occupational safety and health in Production Suction Vessels (KIP) 16 Bangka Ocean Mining Units PT Timah (Persero) Tbk using risk management methods of the Hazard Identification Risk Assessment Determining Control (HIRADC). HIRADC is a working accident identification method with risk assessment as one of the important points for implementing the Occupational Health and Safety Management System (SMK3) based on ISO 45001: 2018. The purpose of this research is to 1) analyze the causes of accidents in 1 (one) month using the formula for frequency rate (FR), safety rate (SR), and incident rate (IR); 2) analyze the accidents data statistics. This type of research is descriptive qualitative with are 2 (two) data collected, namely primary data and secondary data. Primary data was gotten from interviews with employees of KIP 16 Bangka Ocean Mining Units PT Timah (Persero) Tbk and employees of Occupational Safety and Health (K3), whereas secondary data was gotten from K3 documents.

Finding of Suitable Transportation Rate Formula by Using "Velocity - Height - Distance" for Bed Material Load

This research aims to find a suitable transportation rate formula for bed load. Laboratory experiments were conducted in a flume for monitoring and measuring the transportation of sediment particles (bed load) which move by jumping, rolling, or sliding within the flume. This study included two parts. The first part is experimenting using a flume and tracking the particles' movement by analysing the images taken by the camera. The measurements that have been taken are the amount of accumulated bed load particles at the end of the flume, which are distributed along a certain distance during a specific time, thus obtaining measuring data about the amount of accumulated bed load and values of moving distance and the required time for accumulating the particles at the flume end. The accumulated height of bed load is also measured. These experiments were conducted at different low-flow velocities. The second part includes the expression of a formula for bed load transportation rate, which is the product of multiplying the accumulated height of bed load by the velocity of bed load particles with distance at a certain time that was devised in the first part. Through the proposed method of obtaining the measurements in the first part Analysis of bed load particle velocity was done by using (π-theorem) from the results of experiments (Cv, V, ρ, ρS, µ, ds, L). To derive the formula of accumulated bed load height at flume end along a certain distance using Rayleigh’s method and using the results of the experiment (δ, V, g, ds). Finally, there can be found an expression of the bed load transportation rate formula. Checking was made for this formula, which was compared with other researchers' equations using statically measured. It was found that the derived formula was acceptable to calculate the transportation rate of bed load.

Research on the Centrifugal Driving of a Water-in-Oil Droplet in a Microfluidic Chip with Spiral Microchannel

Combining the advantages of droplet-based microfluidics and centrifugal driving, a method for centrifugally driving W/O droplets with spiral microchannel is proposed in this paper. A physical model of droplet flow was established to study the flow characteristics of the W/O droplet in the spiral microchannel driven by centrifugal force, and kinematic analysis was performed based on the rigid body assumption. Then, the theoretical formula of droplet flow rate was obtained. The theoretical value was compared with the actual value measured in the experiments. The result shows that the trend of the theoretical value is consistent with the measured value, and the theoretical value is slightly larger than the experimentally measured value caused by deformation. Moreover, it is found that the mode of centrifugal driving with spiral microchannel has better flow stability than the traditional centrifugal driving structure. A larger regulation speed range can be achieved by adjusting the motor speed without using expensive equipment or precise instruments. This study can provide a basis and theoretical reference for the development of droplet-based centrifugal microfluidic chips.

Measured versus estimated creatinine clearance in critically ill patients with acute kidney injury: an observational study.

BackgroundAcute kidney injury (AKI) commonly occurs in critically ill patients. Estimation of renal function and antibiotics dose adjustment in patients with AKI is a challenging issue.MethodsUrinary creatinine clearance was measured in a 6-hour urine collection from patients with acute kidney injuries. The correlations between different formulas including the modified Cockcroft-Gault, modification of diet in renal disease, chronic kidney disease-epidemiology collaboration, Jelliffe, kinetic-glomerular filtration rate (GFR), Brater, and Chiou formulas were considered. The pattern of the prescribed antimicrobial agents was also compared with the patterns in the available resources.ResultsNinety-five patients with acute kidney injuries were included in the research. The mean age of the participants was 63.11±17.58 years old. The most patients (77.89%) were in stage 1 of AKI according to the Acute Kidney Injury Network criteria, followed by stage 2 (14.73%) and stage 3 (7.36), respectively. None of the formulations had a high or very high correlation with the measured creatinine clearance. In stage 1, Chiou (r=0.26), and in stage 2 and 3, kinetic-GFR (r=0.76 and r=0.37) had the highest correlation coefficient. Antibiotic over- and under-dosing were frequently observed in the study.ConclusionsThe results showed that none of the static methods can predict the measured creatinine clearance in the critically ill patients. The dynamic methods such as kinetic-GFR can be helpful for patients who do not receive diuretics and vasopressors. Further studies are needed to confirm our results.

Analysis of double-layer vibration isolation characteristics of ship power equipment

The vibration isolation device of ship power equipment is the key equipment to protect it from damage, and its performance determines whether the ship can sail safely. To address the problem that it is difficult to achieve the optimal vibration isolation performance of ship’s double-layer vibration isolation, this paper establishes a vibration transmission theory model of ship’s power equipment double-layer vibration isolation system, derives the vibration displacement transmission rate formula based on the model, and studies the influence law of the stiffness ratio of the lower and upper layers of vibration isolation devices, the mass ratio of the intermediate raft frame to the power equipment and the damping of the upper and lower layers of vibration isolation devices on the vibration transmission. The results show that reducing the stiffness ratio of upper and lower layer vibration isolators and increasing the mass ratio of intermediate raft frame and power equipment can reduce the two resonant frequencies and narrow the interval between the two resonant frequencies, and increasing the damping of upper and lower layer vibration isolators can reduce the vibration peak at the two resonant frequencies, but the vibration isolation effect in the high frequency band becomes worse. It provides a theoretical basis for the design optimization of the double-layer vibration isolation system for ship's power equipment.

Passive decoy state phase matching quantum key distribution

In this paper, a passive decoy state phase matching quantum key distribution scheme is proposed based on the heralded pair coherent state light source to make the protocol more practical and safe. Without changing the intensity of the light source, we can derive four different data sets by dividing the raw key data into four groups according to the combined results of detectors in source end. The scheme can make use of the different data sets to estimate the parameters and extract the secret key. The key generation rate formula is derived after the parameter estimation. The performance of the proposed scheme is analyzed with and without taking statistical fluctuation into consideration. The simulation results show that compared with the existing active decoy-state method, the proposed passive method has slightly lower key rate when the transmission distance is short, and has obviously higher key rate when the transmission distance exceeds 406[Formula: see text]km. The maximum safety transmission distance of the proposed scheme is 452[Formula: see text]km which is relatively further. According to the influence of statistical fluctuation, the performance of the proposed scheme declines as the length of the data falls. Even though the data size is [Formula: see text], the max safety transmission distance is also more than 400[Formula: see text]km.

Development of the formula of accurate recovery rate of hydrodynamically incomplete well by penetration degree

The paper presents the methods of penetration of the productive layer. It is noted that the wells in the layers with high thickness are of plane bed and hydrodynamically incomplete by the penetration degree. The formula for an accurate oil recovery rate for such wells has not been developed so far. However, the approximate inaccurate formulas with errors, in one of which a gamma-function is used are suggested. In the reference books, this function is presented in the form of a Table (i.e. tabulated). Due to the complicacy of obtained formula in the borehole set, the solution of theoretic tasks becomes difficult. The complicated filtration flow in the lower part of the deposit in the other approximate method was considered a hemispheric-radial simple flow. The details of the suggested accurate formula for the oil recovery rate of the wells are provided; the plane bottom hole of the well is substituted with an incurved hemispheric surface here. The deposit is divided into two parts: plane radial simple oil flow occurs in the upper part, and hemispheric-radial simple flow in the lower part of it. To obtain the formula for the accurate complete oil recovery rate of this well, two different stationary hydrodynamic tasks have been solved and summarized as well.

The Regression Rate-Based Preliminary Engineering Design of Hybrid Rocket Combustion System

The paper presents a useful engineering model for the design of preliminary hybrid rocket engines. This model involves the experimentally obtained equation regarding the speed of the burning interface between solid fuel and gaseous phase, called the regression rate. This regression rate characterizes the mass rate of the burning fuel and additionally the mass rate of the oxidizer through the imposed ratio of these mass rates during combustion. The preliminary design is applied to combustion using pure HTPB and gaseous oxygen and was developed for three cases, constant regression rate, constant oxygen mass flow rate and constant O/F (ratio of mass rates of oxygen and of fuel). The design evaluates the initial fuel port geometry, the initial mass of fuel and oxygen, the combustion time, the thrust at sea level, and the time-dependent functions of regression rate, of fuel and oxygen mass rates, and of thrust. It was assumed that the regression rate formula applies at any time of combustion. These evaluations can also be applied for other fuel/oxygen couples by knowing the correct formula for the regression rate.

Electron Excitation Rate in Dielectrics Under an Intense Elliptically Polarized Laser Field

Electron excitation in dielectrics is studied for an elliptically polarized laser field. As the first step, we develop an analytical formula for electron excitation rate under elliptically polarized laser as the extension of our previous work [Otobe et al., J. Phys. Soc. Jpn. 88, 024709 (2019)]. In the next step, we calculate the excitation rate depending on the band structure by assuming direction dependence of reduced mass. We find that although the ellipticity decreases the excitation rate significantly in an isotropic system, the energy oscillation of electrons due to the intra-band dynamics in the anisotropic band structure increases the excitation rate with higher ellipticity. Our results indicate that we can control the excitation rate in dielectrics by varying the ellipticity, depending on the band anisotropy.

Primary Study on Medium and Low Carbon Ferromanganese Production by Blowing CO2-O2 Mixtures in Converter

The production of medium- and low-carbon ferromanganese (M-LCFeMn) using the converter method has not been industrialized to date in China due to the high manganese loss and serious erosion of the furnace lining. To solve the above problems and to improve the refining technology of M-LCFeMn, the introduction of CO2 gas into the traditional converter process is proposed. In this study, the oxidation behavior of C and Mn in various conditions was analyzed by blowing different proportions of CO2-O2 mixed gas into the high-carbon ferromanganese (HCFeMn) melt. The results showed that it is feasible to make M-CFeMn by blowing CO2-O2 mixtures, and the Mn loss can be effectively reduced during the decarburization process. It is considered that when the proportion of CO2 reaches 25%, the mixed gas has the best effect on the decarburization and manganese preservation under current experimental situation. Two hypotheses and corresponding rate formulas of decarburization kinetics by using pure oxygen are put forward, and the effect of CO2 on the kinetics of decarburization was studied according to different hypotheses.

Modification in the Mathematical Model of COVID-19 Infection in Urban Polyclinics on the Example of Irkutsk

The study has specified the analytical formula for the rate of covid-19 infection of people susceptible to infection in polyclinics of the city taking into account the statistical correction. Polyclinics serving the local community differ in the number of doctors, capacity and registered population. The distinctions in these indicators can reach two times the value. Those indicators lead to statistical correction in the formula for infection rate of citizens in polyclinics. For the city of Irkutsk, which operates 35 polyclinics, the value of this statistical correction was 32 %. For example, estimates for Irkutsk on 12.28.2021 showed that up to 80 % of covid-19 infections occurred in polyclinics of the city. The findings point to the need to introduce an electronic queue in polyclinics, introduce an online appointment system, issue a sick leave remotely, control the flows of infected and susceptible to infection people in polyclinics.

Performance analysis of spatial multiplexing MIMO-MFSK based on energy detection for fast-fading environments

In fast-fading scattering environments such as high-speed rail and low-altitude communications, mobile communication systems need to quickly and robustly estimate and equalize fast-fading, time-varying channels. Under these circumstances, noncoherent multiple-input multiple-output (MIMO) has received attention in recent years, since it is less influenced by factors such as phase fluctuations and has fewer requirements for channel estimation and synchronization. Spatial multiplexing MIMO-MFSK based on energy detection is different from conventional noncoherent MIMO in that it can achieve higher spatial multiplexing gain in the independent distribution of channel fading statistics. At the receiver, partial real channel state information (CSI) is available, which can improve the capacity while ensuring the reliability of the link. With partial real CSI replacing instantaneous CSI, the system performance is inferior to conventional coherent MIMO under the influence of noise. As a result, it is necessary to analyze its theoretical detection performance. By energy detection, the noise of the MIMO-MFSK system conforms to the generalized gamma distribution. On the basis of this distribution, the optimal decision rule of the system and the symbol error rate (SER) formula are derived. Additionally, we investigate the signal-dependent noise problem of minimum Euclidean distance detection. Numerical results show that the SER formula fits well with the simulation results under the condition of a high signal-to-noise ratio.

On the Origins of the Oceanic Ultraviolet Catastrophe

Abstract We provide a first-principles analysis of the energy fluxes in the oceanic internal wave field. The resulting formula is remarkably similar to the renowned phenomenological formula for the turbulent dissipation rate in the ocean, which is known as the finescale parameterization. The prediction is based on the wave turbulence theory of internal gravity waves and on a new methodology devised for the computation of the associated energy fluxes. In the standard spectral representation of the wave energy density, in the two-dimensional vertical wavenumber–frequency (m–ω) domain, the energy fluxes associated with the steady state are found to be directed downscale in both coordinates, closely matching the finescale parameterization formula in functional form and in magnitude. These energy transfers are composed of a “local” and a “scale-separated” contributions; while the former is quantified numerically, the latter is dominated by the induced diffusion process and is amenable to analytical treatment. Contrary to previous results indicating an inverse energy cascade from high frequency to low, at odds with observations, our analysis of all nonzero coefficients of the diffusion tensor predicts a direct energy cascade. Moreover, by the same analysis fundamental spectra that had been deemed “no-flux” solutions are reinstated to the status of “constant-downscale-flux” solutions. This is consequential for an understanding of energy fluxes, sources, and sinks that fits in the observational paradigm of the finescale parameterization, solving at once two long-standing paradoxes that had earned the name of “oceanic ultraviolet catastrophe.” Significance Statement The global circulation models cannot resolve the scales of the oceanic internal waves. The finescale parameterization of turbulent dissipation, a formula grounded in observations, is the standard tool by which the energy transfers due to internal waves are incorporated in the global models. Here, we provide an interpretation of this parameterization formula building on the first-principles statistical theory describing energy transfers between waves at different scales. Our result is in agreement with the finescale parameterization and points out a large contribution to the energy fluxes due to a type of wave interactions (local) usually disregarded. Moreover, the theory on which the traditional understanding of the parameterization is mainly built, a “diffusion approximation,” is known to be partly in contradiction with observations. We put forward a solution to this problem, visualized by means of “streamlines” that improve the intuition of the direction of the energy cascade.

Flexible Physical Layer Security for Joint Data and Pilots in Future Wireless Networks

In this work, novel physical layer security (PLS) schemes are proposed for orthogonal frequency-division multiplexing (OFDM) to secure both data and pilots in multiple-input multiple-output (MIMO) systems. The majority of previous studies focus on only securing the data without considering the security of the pilots used for channel estimation. However, the leakage of channel state information (CSI) from a legitimate node to an eavesdropper allows the latter to acquire knowledge about the channel of the legitimate nodes. To this end, we propose adaptive and flexible PLS algorithms which can 1) secure data, 2) secure pilots, and 3) jointly secure both data and pilots. Particularly, minimum-phase all-pass channel decomposition is exploited, where the proposed algorithms use the all-pass component to provide security without harming the performance of the legitimate user. In the analysis for data security, we evaluate the secrecy under correlated and uncorrelated eavesdropping channels via closed-form bit error rate (BER) formulas. For pilot security, we analyze the estimated channel’s normalized mean squared error (NMSE) performance. The simulation results and theoretical analysis demonstrate that the proposed algorithms can effectively enhance the communication secrecy of the overall system.

An identification of the tolerable time-interleaved analog-to-digital converter timing mismatch level in high-speed orthogonal frequency division multiplexing systems

<span>High-speed Terahertz communication systems has recently employed orthogonal frequency division multiplexing approach as it provides high spectral efficiency and avoids inter-symbol interference caused by dispersive channels. Such high-speed systems require extremely high-sampling <br /> time-interleaved analog-to-digital converters at the receiver. However, timing mismatch of time-interleaved analog-to-digital converters significantly causes system performance degradation. In this paper, to avoid such performance degradation induced by timing mismatch, we theoretically determine maximum tolerable mismatch levels for orthogonal frequency division multiplexing communication systems. To obtain these levels, we first propose an analytical method to derive the bit error rate formula for quadrature and pulse amplitude modulations in Rayleigh fading channels, assuming binary reflected gray code (BRGC) mapping. Further, from the derived bit error rate (BER) expressions, we reveal a threshold of timing mismatch level for which error floors produced by the mismatch will be smaller than a given BER. Simulation results demonstrate that if we preserve mismatch level smaller than 25% of this obtained threshold, the BER performance degradation is smaller than 0.5 dB as compared to the case without timing mismatch.</span>

Rock dynamic fracture of a novel semi-circular-disk specimen

The relationship between velocity, acceleration, and dynamic fracture toughness during rapid crack propagation is difficult to effectively capture. In this study, a novel semi-circular holed disc bend is proposed to achieve a long fracture path. Hopkinson pressure rods with crack growth and strain gauges are used to impact the semi-circular holed disc bend specimens and to monitor the cracking process of a mode-I fracture. The experiments show that the crack growth speed increases to a critical value after crack initiation and then oscillates as a result of the reflected stress wave. The dynamic propagation fracture toughness ( K IC d ) increases with increasing crack velocity for steady crack propagation; however, this does not apply for unsteady propagation. An experimental–numerical–analytical method is developed to determine the dynamic stress intensity factor , which initially increases with time, then decreases, and ultimately increases again. The acceleration ( v ˙ ) can be used to investigate the unsteady crack propagation process. K IC d values for v ˙ < 0 are greater than those for v ˙ > 0. An energy release rate formula related to v ˙ and the crack propagation velocity ( v ) is proposed and verified by the experiments. A thorough understanding of v , v ˙ , and K IC d is important to analyze high-speed fault rupture processes.

Experimental Study on the Scouring Rate of Cohesive Soil in the Lower Yellow River

The different soil anti scourability in the lower reaches of the Yellow River leads to different scouring and retreating speeds, which has a great influence on river regime evolution. Through the incipient motion scouring test of cemented cohesive soil in the lower reaches of the Yellow River, the physical phenomena of the incipient motion of cohesive soil were expounded, the scouring rate of cohesive soil was calculated, and the relationship between the scouring rate and its influencing factors was established. The results show that when the moisture content of cohesive soil is 43%~61%, the scouring rate is about 0.001~0.03 kg/(m2·s). The scouring rate of cohesive soil with the same particle size varies with the flow shear stress under different deposition duration conditions. Under the same flow rate, the scouring rate of cohesive soil increases with the increase of water content, showing an exponential relationship of increment. Under the same shear stress condition, the scouring rate decreases with the increase of dry density, while the exponential relationship between dry density and scouring rate is not clear when the shear stress is small. With the increase of shear stress, there is an obvious exponential relationship between dry density and scouring rate. Finally, the relationship between the scouring rate and relative residual shear stress was established, and the scouring rate formula suitable for cohesive extremely fine sediment was fitted. The formula can better estimate the scouring rate of the riverbank composed of very fine cohesive sediment and provide support for predicting the scouring and retreating rate of riverbanks in natural rivers.

Uniform stability for laminated beams with time‐dependent boundary conditions

In this paper we consider a laminated beam model. This structure is given by two identical uniform layers on top of each other, taking into account that an adhesive of small thickness is bonding the two surfaces and produces an interfacial slip. In the presence of nonlinear boundary controls modulated by time‐dependent coefficients, we use the multiplier method and overcome the difficulty of finding suitable multipliers to establish a uniform stability result. This result provides an explicit formula for the energy decay rates without imposing any conditions on the coefficients of the system which is more meaningful and realistic from the physical point of view. Our result improves the earlier related results in the literature.

Generalized Lapse Rate Formulas for Use in Entraining CAPE Calculations

AbstractCommon assumptions in temperature lapse rate formulas for lifted air parcels include neglecting mixing, hydrostatic balance, the removal of all condensate once it forms (pseudoadiabatic), and/or the retention of all condensate within the parcel (adiabatic). These formulas are commonly derived from the conservation of entropy, which leads to errors when nonequilibrium mixed-phase condensate is present. To evaluate these assumptions, a new general lapse rate formula is derived from an expression for energy conservation, rather than entropy conservation. This new formula incorporates mixing of the parcel with its surroundings, relaxes the hydrostatic assumption, allows for nonequilibrium mixed-phase condensate, and can be formulated for pseudoadiabatic or adiabatic ascent. The new formula is shown to exactly conserve entropy for reversible ascent. Predictions by the new formula are compared to that of older and less general formulas. The errors in previous formulas arise from the assumption of hydrostatic balance, which results in considerable warm biases due to the neglect of the energy sink from buoyancy. Predictions of ascent with entrainment using the new formula are then compared to parcel properties along trajectories in large eddy simulations. Simulated parcel properties are better predicted by the formula using a diluted analogy to adiabatic ascent, wherein condensate is diluted at the same rate as other parcel properties, than by the diluted analogy to pseudoadiabatic ascent, wherein all condensate is removed. These results suggest that CAPE should be computed with adiabatic, rather than pseudoadiabatic, parcel ascent.

Map Lattices Coupled by Collisions: Hitting Time Statistics and Collisions Per Lattice Unit

We study map lattices coupled by collision and show how perturbations of transfer operators associated with the spatially periodic approximation of the model can be used to extract information about collisions per lattice unit. More precisely, we study a map on a finite box of L sites with periodic boundary conditions, coupled by collision. We derive, via a non-trivial first-order approximation for the leading eigenvalue of the rare event transfer operator, a formula for the first collision rate and a corresponding first hitting time law. For the former we show that the formula scales at the order of Lcdot varepsilon ^2, where varepsilon is the coupling strength, and for the latter, by tracking the L dependency in our arguments, we show that the error in the law is of order Oleft( C(L)frac{Lvarepsilon ^2}{zeta (L)}cdot left| ln frac{Lvarepsilon ^2}{zeta (L)}right| right) , where zeta (L) is given in terms of the spectral gap of the rare event transfer operator, and C(L) has an explicit expression. Finally, we derive an explicit formula for the first collision rate per lattice unit.