Load Adjustment Research Articles

SIMULASI PENYESUAIAN BEBAN PADA TRANSFORMATOR DI GARDU INDUK NUSA DUA

The rapid development in the South Kuta region has resulted in an increase in the demand for electricityenergy that must be supplied by the 150 kV Nusa Dua substation. An increase in the amount of load results in anincrease in the load that must be borne by the transformer. To prevent losses due to overload, a load adjustmentsimulation is performed on the transformer at the Nusa Dua Substation. Load flow simulation is done using ETAPsoftware with the subject of the power transformer load along with the load-feeders. The purpose of the simulation isto know the loading conditions and power loss of the Nusa Dua substation system. Furthermore, the transformerload adjustment scenario is designed, then simulated again with ETAP software to determine changes in the loadingconditions and the power loss in the Nusa Dua substation system. Simulation results in existing condition withnormal operation, transformer 1 load is 69,8% and transformer 3 is 71,8% with a total power loss of 14,1%. After 3planning scenarios for transformer load adjustment, scenario 2 is the bestl scenario in short term with the loading ontransformer 1 is 50,4%, transformer 2 is 45,9%, and transformer 3 is 45,1% with total power loss of 9,16%. While forthe long term, scenario 3 is recommended by adding a new transformer unit. Transformer 1 loading is 50,9%,transformer 2 is 45,9%, and transformer 3 is 45,1% with a total power loss of 9,24%.

Part-load performance analysis and comparison of supercritical CO2 Brayton cycles

The system that integrates solar power tower, molten salt thermal storage, and supercritical CO2 (S-CO2) Brayton cycle has emerged as a promising technology to provide a dispatchable power output following the power demand. Studying the part-load performance of the S-CO2 Brayton cycle is crucial to achieve an efficient system operation during power load adjustment. In this work, the performance of four typical S-CO2 Brayton cycles including simple recuperative cycle, reheating cycle, recompression cycle, and intercooling cycle are analyzed and compared under part-load conditions. The optimal cycle layouts under different power demand scenarios are revealed. Results show that the reheating cycle achieves higher efficiency than the simple recuperative cycle, and the recompression cycle and intercooling cycle perform better than the reheating cycle under part-load conditions. However, the intercooling cycle is more efficient than the recompression cycle only when the load exceeds 60%. Given that the relative reduction in the reheating cycle efficiency is minimal as the load decreases, this cycle shows the best response to the requirement of wide-range load adjustment. When the ratio of the actual total electricity generation to the maximum total electricity generation in a certain period is lower than 62.5%, the recompression cycle performs better. When this ratio is higher than 68.3%, the intercooling cycle performs better. In general, the efficiency of intercooling cycle is not significantly improved compared with that of the recompression cycle under the load-following scenarios.

Determining the characteristics for the rational adjusting of an fuel-air mixture composition in a two-stroke engine with internal carburation

An operating process for engines with spark ignition and direct fuel injection engines which ensures the formation of a stratified lean fuel-air charge under the modes of partial loads and the power composition of the fuel-air mixture at high loads has been developed. The design of a two-stroke spark-ignition engine was modernized by installing a direct fuel injection system, placing the nozzle in the cylinder wall, and changing the combustion chamber shape. A procedure of adjustment of the composition of the fuel-air mixture in the cylinder of a two-stroke spark-ignition engine has been developed. The procedure features the recording of engine parameters and indicators at a constant cycle fuel feed and intake air adjustment. The proposed procedure makes it possible to more accurately adjust the composition of the fuel-air mixture due to a more accurate dosage of air than the cycle fuel feed. Experimental studies were carried out and adjustment characteristics were constructed in terms of the air-fuel mixture composition in the cylinder of a two-stroke engine with a developed operating process. Load characteristics (at n=3,000 rpm) of rational adjustment in terms of economy and maximum power were constructed based on data on the adjustment characteristics for the composition of the fuel-air mixture. It was found that in terms of the load characteristic of rational economy adjustment, the composition of the fuel-air mixture in the engine cylinder (λ cyl.ec ) varied from 1.31 to 1.94 and the minimum fuel consumption was g e min =259 g/(kWh). In terms of the load characteristic of rational power adjustment, the composition of the fuel-air mixture in the engine cylinder (λ cyl. pow ) varied from 1.31 to 1.7, and the fuel consumption at partial loads was g e =270 g/kWh. Characteristics of airflow rate depending on the cycle fuel feed can be used to change the composition of the fuel-air mixture with automatic adjustment of the engine load

Interplay of erythropoietin, fibroblast growth factor 23, and erythroferrone in patients with hereditary hemolytic anemia

AbstractRecently, erythropoietin (EPO) was identified as regulator of fibroblast growth factor 23 (FGF23). Proteolytic cleavage of biologically active intact FGF23 (iFGF23) results in the formation of C-terminal fragments (cFGF23). An increase in cFGF23 relative to iFGF23 suppresses FGF receptor signaling by competitive inhibition. EPO lowers the i:cFGF23 ratio, thereby overcoming iFGF23-mediated suppression of erythropoiesis. We investigated EPO-FGF23 signaling and levels of erythroferrone (ERFE) in 90 patients with hereditary hemolytic anemia (www.trialregister.nl [NL5189]). We show, for the first time, the importance of EPO-FGF23 signaling in hereditary hemolytic anemia: there was a clear correlation between total FGF23 and EPO levels (r = +0.64; 95% confidence interval [CI], 0.09-0.89), which persisted after adjustment for iron load, inflammation, and kidney function. There was no correlation between iFGF23 and EPO. Data are consistent with a low i:cFGF23 ratio. Therefore, as expected, we report a correlation between EPO and ERFE in a diverse set of hereditary hemolytic anemias (r = +0.47; 95% CI, 0.14-0.69). There was no association between ERFE and total FGF23 or iFGF23, which suggests that ERFE does not contribute to the connection between FGF23 and EPO. These findings open a new area of research and might provide potentially new druggable targets with the opportunity to ameliorate ineffective erythropoiesis and the development of disease complications in hereditary hemolytic anemias.

Modelling immune deterioration, immune recovery and state-specific duration of HIV-infected women with viral load adjustment: using parametric multistate model

BackgroundCD4 cell and viral load count are highly correlated surrogate markers of human immunodeficiency virus (HIV) disease progression. In modelling the progression of HIV, previous studies mostly dealt with either CD4 cell counts or viral load alone. In this work, both biomarkers are in included one model, in order to study possible factors that affect the intensities of immune deterioration, immune recovery and state-specific duration of HIV-infected women.MethodsThe data is from an ongoing prospective cohort study conducted among antiretroviral treatment (ART) naïve HIV-infected women in the province of KwaZulu-Natal, South Africa. Participants were enrolled in the acute HIV infection phase, then followed-up during chronic infection up to ART initiation. Full-parametric and semi-parametric Markov models were applied. Furthermore, the effect of the inclusion and exclusion viral load in the model was assessed.ResultsInclusion of a viral load component improves the efficiency of the model. The analysis results showed that patients who reported a stable sexual partner, having a higher educational level, higher physical health score and having a high mononuclear component score are more likely to spend more time in a good HIV state (particularly normal disease state). Patients with TB co-infection, with anemia, having a high liver abnormality score and patients who reported many sexual partners, had a significant increase in the intensities of immunological deterioration transitions. On the other hand, having high weight, higher education level, higher quality of life score, having high RBC parameters, high granulocyte component scores and high mononuclear component scores, significantly increased the intensities of immunological recovery transitions.ConclusionInclusion of both CD4 cell count based disease progression states and viral load, in the time-homogeneous Markov model, assisted in modeling the complete disease progression of HIV/AIDS. Higher quality of life (QoL) domain scores, good clinical characteristics, stable sexual partner and higher educational level were found to be predictive factors for transition and length of stay in sequential adversity of HIV/AIDS.

Calculation Model of Electric Load Adjustment Capacity of Low Vacuum Heat Supply Unit and its Application

Based on the thermal balance of steam turbine and condenser, the calculation model of electric load adjustment capability of low vacuum heating unit is established by iterative calculation method. Taking a low-vacuum heat supply unit in Shandong as the research object, the electric load adjustment capability is measured. Compared with the test results, the calculation model of this paper has higher precision.

Running for your life: A qualitative study of champion long-distance runners’ strategies to sustain excellence in performance and health

ObjectivesTo investigate champion long-distance runners’ strategies for managing injury and illness symptoms and staying well. DesignQualitative research study. MethodsTwelve long-distance runners were interviewed immediately after having competed in World Championships finals. Thematic analysis was used to categorise and structure the data. The results were presented as primary themes and overarching constructs representing connections between the primary themes. ResultsThe champion runners’ basic tactic to manage symptoms of ill health was characterized by rapid adjustment of sports load and a strong incentive to learn from experience and professional advice. This tactic was named here educated flexibility. A secondary exigency tactic was associated with reaching short-term goals and a consequential acceptance of health hazards. The runners used economic and other environmental strain to explain use of the exigency tactic. Most champion runners’ long-term strategy to stay well included both tactics successfully combined to maintain a performance level assuring a regular income. Avoidance of letting environmental strain and health problems create vicious circles was at the centre of these strategies. ConclusionsChampion runners’ main strategy to stay well and sustain their superiority in performance was characterized by constantly paying attention to symptoms of ill health, listening to medical advice, and not letting environmental strain interfere with adjustment of sports load. Many top-level runners originate from global regions where formal education programs and health insurance plans are poorly regulated and supported. Bio-psychosocial models including empowerment at individual and systems levels should be considered when health services are planned for professional runners.

Polypyrrole decorated metal-organic frameworks for supercapacitor devices.

Due to their large specific surface areas and porosity, metal–organic frameworks (MOFs) have found many applications in catalysis, gas separation, and gas storage. However, their use as electronic components such as supercapacitors is stunted due to their poor electrical conductivity. We report a remedy for this by combining the MOF structure with polypyrrole (PPy), a well-known conductive polymer. Three MOFs are studied for modification to this end: CPO-27-Ni and CPO-27-Co (M2DOBDC, M = Ni2+, Co2+, DOBDC = 2,5-dihydroxy-1,4-benzenedicarboxylate) and HKUST-1 (Cu3(BTC)2, BTC = 1,3,5 benzenetricarboxylate). The gravimetric capacitance of pure MOFs is boosted several orders of magnitude after reinforcement of PPy (e.g., from 0.679 to 185 F g−1 for HKUST-1 and PPy–HKUST-1, respectively), and is much higher than reported for pure PPy. In total, these PPy-d-MOFs exhibit specific capacitances up to 354 F g−1, retaining 70% of this value even after 2500 cycles. Among them, the highest capacitance is found for PPy–CPO-27-Ni (354 F g−1), followed by PPy–CPO-27-Co (263 F g−1) and PPy–HKUST-1 (185 F g−1). The maximum operating potential for these electrodes is 0.5 V, which is restricted by the contact of MOF with aqueous electrolyte and with extremely low PPy content. As a solution, higher PPy loading and rational adjustment of particle size and porosity of both MOF and PPy are recommended so that the MOF/electrolyte interface is limited, leading to more robust electrode. The work completed here describes a highly promising approach to tackling the electrically insulating nature of MOFs, paving the way for their use in electrochemical energy storage devices.

Branched Secondary Alcohol Ethoxylate, Ammonium Thiosulfate, Calcium Polysulfides-Thiosulfate, and Fish Oil Effects on Blossom Thinning, Fruit Set and Quality of Peaches and Nectarines

Total crop load has an inverse relationship with fruit size, while larger fruit size is often demanded by the peach and nectarine markets. Hand-thinning is extremely expensive, and thus, crop load adjustment, using blossom thinners is a crucial practice to ensure production of commercially acceptable fruit size and yield efficiency in stone fruit. In this study, the influence of branched secondary alcohol ethoxylate (Tergitol TMN-6) and/or ammonium thiosulfate (ATS), Crocker Fish Oil (FO), and a mixture of calcium polysulfides and thiosulfate (lime sulfur) on fruit set and quality attributes in peaches (Prunus persica) and nectarines (P. persica var. nectarina) were studied. All blossom thinners reduced fruit set in “Summer Lady” peach in both 2016 and 2017. Fruit sets in “Summer Lady” peach trees with a double application of Tergitol TMN-6 at the rate of 7.5 or 10 mL ·Lˉ1, each rate applied at 40% and 80% bloom, were lower than those receiving the same rates of this chemical only at 80% bloom, but they were similar to those receiving a single Tergitol TMN-6 spray at 15 mL·Lˉ1 at 80% or 100% bloom. “Summer Lady” peach trees receiving FO at 20 mL·Lˉ1 plus lime sulfur at 25 mL·Lˉ1, once at 40% bloom and again at 80% bloom had lower fruit set as compared to Untreated Control but the fruit set was higher than those with any Tergitol-TMN-6 spray. Tergitol TMN-6 at 12 m·Lˉ1 at 100% bloom or 10 mL·Lˉ1 all stages of bloom reduced fruit set in “Zee Lady” and “Snow Giant” peaches. In “Snow Giant” peach, trees receiving Tergitol TMN-6 at all concentrations and blossom stages had significantly higher fruit weight as compared to the trees of Un-treated Control. Applications of Tergitol TMN-6 at all concentrations at 80% bloom reduced fruit set in “Red Globe” and “Elberta” peaches in Utah. ATS and FO slightly reduced fruit set in peaches but they were less effective than Tergitol TMN-6 in all cases. Overall, it is concluded that efficacy of blossom thinners depends on the rate of thinners, temperature, cultivar and stage of bloom development.

Self-selected vs programed load adjustment methods in strength and body composition: a pilot study

Self-selected vs programed load adjustment methods in strength and body composition: a pilot study

상체 근력 운동을 위한 단계별 근력 부하 조정 시스템

본 연구에서는 다수의 스프링을 사용하여 운동 부하를 자동으로 부여하는 운동기구에 대한 설계와 제작을 진행하였다. 등가 스프링의 강성을 조절하기 위해서 스프링의 개수를 자동으로 선택할 수 있는 기구를 설계하였으며, PID 제어를 이용하여 별도의 외부 센서 없이 정확한 위치에 훅(hook)이 걸릴 수 있도록 하였다. 사용자가 당기는 길이로 스프링의 변형량을 측정하고, 선택된 스프링의 개수에 의한 등가 스프링 강성을 계산하여 사용자의 근력을 산출할 수 있도록 하였다.

Study on load adjustment range of 150 MW unit in heating season after high back pressure reform

New energy is experiencing rapid development, but it brings great challenges to peak shaving of power grid. Especially in the stage of wind power outbreak in winter, the operation mode of heat supply unit “fixing electricity by heat” aggravates the difficulty of peak shaving of power grid. Taking 150 MW double-extraction heat-supply unit as an example, the load adjustment intervals under different heating modes are enumerated by field test method for reference of power generation enterprises and power grid dispatching operation.

A Real-Time Adjustment of Conventional Under-Frequency Load Shedding Thresholds

This letter presents an innovative and easy-to-implement approach for the improvement of conventional under-frequency load shedding, where frequency thresholds are adjusted locally in real time. The proposed method, which would be implemented locally in each under-frequency relay, estimates the forthcoming frequency evolution and adjusts the predefined frequency thresholds values according to the estimated frequency nadir. As a result, significantly improved frequency response by reducing overshoots can be observed. Concept verification was performed by means of Slovenian power-system model simulations, where the comparison with conventional constant-threshold setting showed a high level of efficiency.

Dynamic Control Method of Thermal Power Units Compensating for Wind Power Disturbance

The randomness and volatility of wind power generation are the main reasons restricting the capacity of power grid to absorb wind power. Thermal power units are the main force of power grid frequency modulation. The speed of load adjustment rate determines their response ability to power grid load. Based on the analysis of the characteristics of wind power generation, the nonlinear multiscale decomposition of the automatic power generation control (AGC) load command is carried out. Combined with the different load regulation rates of different types of units, the rational allocation of unit combinations can effectively ensure the power grid load regulation capacity and compensate the random disturbance of wind power.

Initial Fluid Resuscitation Following Adjusted Body Weight Dosing in Sepsis and Septic Shock.

IntroductionFluid administration is considered a fundamental part of early sepsis treatment. Despite abundant research, fundamental questions about the amount of fluids to be given remain unanswered. Recently, the idea of adjusting the fluid load to the ideal body weight emerged, as obesity rates are increasing, and fluid overload was proven to increase mortality.Aim of the studyThe study aimed to determine whether advanced haemodynamic monitoring supports the adjustment of the initial fluid load to the ideal body weight (IBW).MethodsSeventy-one patients with sepsis and septic shock were enrolled in the study. The initial fluid resuscitation was performed using local protocols. The haemodynamic status was assessed after the initial fluid load by transpulmonary thermos-dilution technique and the renal outcome recorded at twenty-four hours.Results68.6% of the patients included in the study had weight disorders ranging from BMI+20% to morbid obesity. Before IBW adjustment, only 49.3% received the 30 ml/kg fluid load recommended by Surviving Sepsis Campaign Guidelines (2016) (SSC). After IBW adjustment, 70.4% received the recommended fluid dose. The difference in fluid load/kg before and after the bodyweight adjustment was statistically significant (p<0.01). After the initial fluid load, the majority of the macro haemodynamic parameters were in the targeted range. There was no statistically significant difference between the urinary output outcome at 24 hours or the 28 days mortality rates between the patients resuscitated by the SSC and those who received less fluid.ConclusionsAdvanced haemodynamic monitoring was in favour of adjusting the initial fluid load to the IBW. There were no statistically significant differences either in the urinary output outcome at twenty-four hours, or in the twenty-eight-day mortality rates between the patients who received the 30 ml/kg IBW and those who received less than 30 ml/kg IBW.

Adapting load limiter deployment for frontal crash diversity

Objective: Current European restraint systems may not realize their full protection potential in real-world frontal crashes because they are highly optimized for specific conditions. This research sought to quantify the potential benefit of adapting seat belt load limit thresholds to a wider range of occupant and crash characteristics.Methods: Numerical simulations using Hybrid III dummies were conducted to determine how varying load limiter thresholds could affect occupant kinematics and injury outcome in frontal impacts. Occupant–compartment models were developed with a restraint system consisting of a frontal airbag and a 3-point belt with retractor, buckle pretensioner, and load limiting at the shoulder. Load limiting threshold was varied in 5 frontal impact scenarios, covering as wide a range of real frontal crash conditions as possible. The simulated thoracic injury risks were converted into injury probability values using Abbreviated Injury Scale (AIS) 2+ age-dependent thoracic risk curves. These values were then applied to a British real-world frontal impact sample to determine the injury reduction potential of optimized load limiting, taking into account occupant seating position, impact scenario, occupant size, and occupant age and assuming that an appropriate adaptive system was fitted to all cars.Results: In low-severity impacts, a low load limit provided the best chest protection, without increasing risk to other body regions, for both the 50th and 95th percentile dummies in both front seating positions. In high-severity impacts, the low limit was not recommended because it allowed the driver dummy to move into close proximity with the vehicle interior, although there appeared to be some benefit of lower load limiting for the 50th percentile front passenger dummy, due to the increased ride down space in that seating position. Adapting the load limit showed no injury reduction potential for 5th percentile drivers. Utilizing the best load limit threshold in real-world crashes could reduce the number of occupants with AIS 2+ chest injuries from belt loading from 377 to 251 (a 33% reduction), correspondingly reducing the number of occupants with AIS 2+ chest injuries (from all sources) in the whole frontal impact population from 496 to 370. This is a reduction in injury rate from 6.4% to 4.8%.Conclusions: The concept of an adaptive load limiter shows most promise in low-speed frontal crashes where it could lower the AIS 2+ chest injury risk for most front seat occupants, except the smallest of drivers. Generally, adaptive limiters show less potential effectiveness with increased crash severities. Overall, an intelligent adjustment of load limiting threshold could result in a reduction of at least a third of front seat occupants with AIS 2+ chest injuries associated with restraining loads and an overall reduction in AIS 2+ chest injury rate in frontal crashes from 6.4% to 4.8%

Power coefficient measurements of a novel vertical axis wind turbine

AbstractWind tunnel experiments were performed to evaluate the power coefficients of three vertical axis wind turbines (VAWTs), namely, (a) conventional VAWT (two‐bladed troposkien shape), (b) novel 50% shifted troposkien shape‐vertical axis wind turbine (50% STS‐VAWT), and (c) novel 100% STS‐VAWT. All turbines had the same height, swept area, and NACA0015 airfoil with the same chord length. During the power coefficient measurements for each one of the turbines, the wind tunnel velocity was varied while the turbine rotation was kept constant through rheostatic load adjustment. Two different turbine rotations were used (600 rpm and 700 rpm). The resulting tip speed ratios (TSRs) ranged from approximately 2 to 6 in the current investigation. Both the power coefficients and the tip speed ratios were corrected against wind tunnel blockage effects. The 50% STS‐VAWT model showed an overall better aerodynamic performance (both corrected and uncorrected power coefficients) when compared against the other two configurations, likely due to a combination of (a) power generation increased due to blade‐wake interaction (BWI) reductions and (b) power generation capacity related to the blade length of each turbine.

The Development of the Physiological Adjustment of Physical Loads and Its Impact on the Circulatory System and the Skills of Football Players

Summary This research was focused on the important question, what is the effect of the development of physiological adjustment of the physical load on the respiratory system and the performance of the skills of football players. In addition we tried to comfirm the relationship between the physical qualities and the performance of the skills. We have applied the experimental approach which best suits to this type of question. Proposing a program based on the physiological adjustment of the respiratory system, we applied the approach to a sample of twenty players (table 3), which were a deliberate sample divided into experimental and control, during the general physical preparation. The results confirmed that there are statistically significant differences between the pre-test and post-test of the experimental sample in both the respiratory system tests and the functional performance tests, in addition to statistical differences between the control and experimental groupe in the post-test.

Analysis of the Day-ahead Deviation Plan and Research on the Real-time Scheduling of Photovoltaic Greenhouses Based on Exergy Theory

For the correction problem of day-ahead plan deviation caused by energy prediction deviation in day-ahead scheduling stage of photovoltaic greenhouses, an exergy analysis method is used to propose the deviation model of heat required for photovoltaic greenhouses. Based on the deviation model, a real-time optimization scheduling model is established. The deviation model not only considers the non-negligible exergy loss during heating process of pipes, but also considers the difference between heat and thermal exergy affected by the actual indoor temperature. The goal of the real-time scheduling model is to minimize the absolute value of the difference between the energy supply and demand prediction deviation to be corrected and the adjustment of multi-form energy storage and electric loads, so that develop the real-time adjustment plan of energy storage and electric loads. The analysis results of the actual photovoltaic greenhouse show that of the heat required by a greenhouse based on the exergy theory calculation, the exergy loss of the heating process accounts for about 10%–20% of the total thermal exergy required and it cannot be ignored, so the calculation results can reflect the actual heat required more accurately and the greenhouse temperature is more suitable for plant growth. Moreover, the proposed real-time scheduling model can correct the deviation of the day-ahead plan and improve local consumption. The promotion ratio can reach 7%. Finally, the farmers’ electricity purchases cost is reduced. Thereby the effectiveness of the proposed heat deviation model and real-time scheduling model is verified.

Operation Optimization of Multi-District Integrated Energy System Considering Flexible Demand Response of Electric and Thermal Loads

Multi-district integrated energy system (IES) can make full use of the complementary characteristics of district power and thermal system, and loads in different districts. It can improve the flexibility and economy of system operation, which has a good development prospect. Firstly, based on the general energy transfer model of the district heating network (DHN), the DHN system is described by the basic equations of the heating network and nodes considering the characteristics of the transmission time delay and heat loss in pipelines. A coupling model of DHN and multi-district IES is established. Secondly, the flexible demand response (FDR) model of electric and thermal loads is established. The load characteristics of each district in IES are studied. A shiftable load model based on the electric quantity balance is constructed. Considering the flexibility of the heat demand, a thermal load adjustment model based on the comfort constraint is constructed to make the thermal load elastic and controllable in time and space. Finally, a mixed integer linear programming (MILP) model for operation optimization of multi-district IES with the DHN considering the FDR of electric and thermal loads is established based on the supply and demand sides. The result shows that the proposed model makes full use of the complementary characteristics of electric and thermal loads in different districts. It realizes the coordinated distribution of thermal energy among different districts and improves the efficiency of thermal energy utilization through the DHN. FDR effectively reduces the peak-valley difference of loads. It further reduces the total operating cost by the coordinated operation of the DHN and multi-district IES.