Cycle Efficiency Research Articles

P-251 Denudation time is crucial to increase the proportion of top-quality embryos in egg donation cycles

Abstract Study question How do different denudation times affect in the efficiency of the egg donation cycles? Summary answer Undetected in vitro matured oocytes, resulting from delayed denudations, contribute to a decreased top-quality blastocyst ratio. What is known already While the timeframe for sperm microinjection in ICSI cycles is widely agreed upon (2-6 hours post-oocyte retrieval), no definitive denudation time preference has been established. Published studies diverge on the advantages of early or late denudation, assessing the impact of trigger-to-denudation time (T-D time) on oocyte maturation. Advocates of early denudation contend it prevents oocyte aging, reducing in vitro culture and enhancing outcomes. These studies, often using data from cycles with own oocytes, exhibit high variability and inconsistent conclusions. The present work introduces an alternative hypothesis on the benefits of early denudation, employing a more stable study model. Study design, size, duration This retrospective study encompasses oocyte donation cycles, employing a short antagonist protocol and ovum pick-up 35.5 hours post-trigger, conducted from January 2019 to July 2023 including 1,559 stimulations. Additionally, 1,275 ICSI cycles without detected sperm pathologies derived from these stimulations were examined to evaluate the influence of T-D time on the reproductive outcomes. Six comparable groups were established by segmenting the sample according to T-D time, annotated in 30-minute intervals (36.5h to 39h). Participants/materials, setting, methods Rates of MII, MI, and nonviable oocytes were examined among 1,559 stimulations resulting in 29,671 oocytes (36.5h:187-stimulations/3,178-oocytes; 37h:226/3,836; 37.5h:614/11,921; 38h:329/6,884; 38.5h:119/2,322; 39h:84/1,530). Additionally, in 1,275 ICSI cycles involving 11,333 MII-oocytes (36.5h:117-ICSI cycles/1,027-MII; 37h:130/1,133; 37.5h:502/4,426; 38h:316/2,925; 38.5h:120/1,041; 39h:90/781), comparisons were made for fertilization, abnormal fertilization, ICSI degeneration, useful day 5/6 blastocyst (transferred or cryopreserved; >3BB-top and ≤3BB-good quality by Gardner score), pregnancy, and live birth rates. Statistics were ANOVA, Chi-square test and Pearson’s correlation. Main results and the role of chance Oocyte maturation profile assessment reveals that groups with later denudation exhibit a higher proportion of MII-oocytes (36.5h:80.71%; 37h:81.04%; 37.5h:81.26%; 38h:80.83%; 38.5h:84.84%; 39h:85.29%; r:0.8475; p < 0.05), reaching significance from 38.5h onward (p < 0.05). This is complemented by a strong negative correlation between T-D time and MI rate (36.5h:5.51%; 37h:5.32%; 37.5h:4.64%; 38h:4.17%; 38.5%h:3.27%; 39h:2.94%; r:-0.9881; p < 0.05), with significant declines at 38h and 38.5h (p < 0.05). No correlation between useless oocytes proportion and T-D time was observed (r:-0.5983; p = 0.21). This illustrates that certain MI-collected oocytes progressively mature during in vitro culture and subsequently, upon denudation, are classified as MII. This overestimates in vivo-matured oocytes. No differences attributed to T-D time were observed regarding fertilization, abnormal fertilization, or ICSI degeneration rates. While time does not affect the rate of useful embryos achieved (36.5h:49.4%; 37h:46.4%; 37.5h:44.6%; 38h:48.0%; 38.5h:50.6%; 39h:47.2%; r:0.1342; p = 0.80), it has an impact on the blastocysts quality. The proportion of top-quality blastocysts (>BB) progressively decreases with T-D time (36.5h:86.2%; 37h:85.2%; 37.5h:85.4%; 38h:81.2%; 38,5h:80.5%; 39h:80.5%; r:-0.925; p < 0.05). Out of 1,794 single embryo transfers, 1,477 have conclusive outcome. No implication of T-D time was detected in pregnancy rate (36.5h:59.88%; 37h:64.07%; 37.5h:61.54%; 38h:65.02%; 38.5h:59.55%; 39h:62.26%; r:0.0489; p = 0.93) or live birth rate (36.5h:40.31%; 37h:51.85%; 37.5h:39.12%; 38h:45.04%; 38.5h:41.83%; 39h:37.96%; r:-0.375; p = 0.46). Limitations, reasons for caution This study has inherent limitations as a retrospective analysis. Additionally, the potential effects of a denudation earlier than 36.5 hours post-trigger, not yet standardized in the laboratory, were not assessed. Wider implications of the findings Delayed denudation may benefit autologous IVF by fostering in vitro oocyte maturation. In egg donation cycles, early denudation is preferable for stringent selection of in vivo matured oocytes, yielding superior results. Additionally, shortening or eliminating incubation periods would enhance the automated sequence of diverse processes during an IVF cycle. Trial registration number not applicable

Performance, economic, and statistical analysis assessment for the hybrid solar dish concentrator with turbine, generator, and reverse osmosis desalination unit

The development of a thermodynamically modeled hybrid commercial solar dish with reverse osmosis is conducted in this study with a rated concentrate thermal and a receiver temperature of 853 °C. To simulate and assess the performance characteristics of the suggested TJ-SDC/RO hybrid system in the city of Tianjin-republic of China, a theoretical model was created and built with MATLAB application. A daily and yearly performance study of the TJ-SDC/RO system under investigation is accomplished. Furthermore, energy analysis viability is achieved in order to evaluate the TJ-SDC/RO system’s life cycle. According to the findings, the suggested TJ-SDC/RO system can produce enough desalinated water to meet daily changes in solar radiation. In June of Tianjin-China’s climate, the superior efficiency of the Rankine cycle was 33.92 %, while the SDC-RO system maximum cycle efficiency peaked at 24.95 % with minimum production costs per unit of electricity of 0.0902 $/kW.h and average water production costs yearly 7.09 $/m3. A mathematical model by Minitab commercial software of the nonlinear regression technique is used with an adjusted R2 of 0.99999485, which indicates the accuracy and reliability of the prediction correlation.

Unlocking the power of LiOH: Key to next-generation ultra-compact thermal energy storage systems

This study explores the potential of untapped lithium hydroxide (LiOH) as a phase change material for thermal energy storage. By overcoming the challenges associated with the liquid LiOH leakage, we successfully thermal-cycled LiOH in a laboratory scale experimentation, and observed its stability (>500 thermal cycles), without chemical decomposition. This step has never been performed to date. Its solid-to-liquid reversible transitions temperatures and related solidification/melting enthalpies values have been verified. Then, the first experimental characterization of LiOH's thermal properties shows unexpected values for its heat capacity, thermal conductivity and diffusivity, in contradiction with the few ones available in literature. This opens avenues for LiOH's applications for the storage of sensible and latent heat, as shown through the increased cycle efficiency potential of a thermal energy storage system if based on its energy storage capacity; up to six times more volumetric energy density compared to traditional Solar Salt-based systems used in the solar tower plant (4.5 GJ/m3 vs. 0.76 GJ/m3 over 1000 thermal cycles). Additionally, we observed a softening phenomenon that occurs inconsistently during heating, but which may account for its excellent melting properties and the interplay with other raw chemicals. This new insight contributes certainly to the underlying mechanisms in the synthesis of another promising heat storage material in development: the peritectic compound Li4Br(OH)3. This pioneering work suggests LiOH as a promising ultra-compact thermal energy storage material for filling the intermediary gap from current to next-generation solar power plants, although its large-scale application requires further investigation to achieve economic viability.

A case study of thermal performance of gas-steam combined cycle with gas turbine inlet air cooling and condenser deep cooling

To enhance power generation during high summer temperatures and address the power supply and demand imbalance in gas-steam combined cycle, this study explored the exhaust gas waste heat refrigeration scheme, along with the optimal scheduling of cooling capacity between the precooling of inlet air for the gas turbines and deep cooling for condenser in steam cycle. Using the Ebsilon software, we investigate the thermal performance of the gas cycle, steam cycle, and the overall gas-steam combined cycle under various off-design operating conditions, including varying cooling capacity distributions, ambient temperatures, and generation loads. Based on our calculations, it is advisable to prioritize cooling capacity for precooling the ambient air for the gas cycle, balancing power generation and thermal efficiency. After the transformation, the power generation of the gas-steam combined cycle remains relatively stable across varying ambient temperatures, achieving a significant 10.9 % increase compared to pre-transformation levels under a 39 °C ambient temperature and 100 % generation load. Furthermore, the thermal efficiency of the gas-steam combined cycle improves by 1.11 % under a 40 % generation load condition. As ambient temperatures rise, the benefits of the inlet air cooling scheme become more apparent, validating its effectiveness in addressing the inherent summer power supply and demand challenges.

A case study of lean digital transformation through robotic process automation in healthcare

Under Taiwan's National Health Insurance (NHI) system, it's crucial for all healthcare providers to accurately submit medical expense claims to the National Health Insurance Administration (NHIA) to avoid incorrect deductions. With changes in healthcare policies and adjustments in hospital management strategies, the complexity of claiming rules has resulted in hospitals expending significant manpower and time on the medical expense claims process. Therefore, this study utilizes the Lean Six Sigma DMAIC (Define, Measure, Analyze, Improve, Control) management approach to identify wasteful and non-value-added steps in the process. Simultaneously, it introduces Robotic Process Automation (RPA) tools to replace manual operations. After implementation, the study effectively reduces the process time by 380 min and enhances Process Cycle Efficiency (PCE) from 69.07 to 95.54%. This research validates a real-world case of Lean digital transformation in healthcare institutions. It enables human resources to be allocated to more valuable and creative tasks while assisting hospitals in providing more comprehensive and patient-centric services.

Pool boiling performance of R32/R290 and R32/R1270 blends as potential alternatives to R410A

The implementation of the climate change agreement intensified the actions of government agencies and industries to phase out refrigerants with high global warming potential (GWP). This study investigated refrigerant blends as possible low GWP alternatives for R410A in a refrigerating application. The cycle efficiency and flammability of binary and ternary blends among 19 pure refrigerants were evaluated based on an ideal vapor compression refrigeration cycle model with application conditions of water chillers. The mixtures R32/R290 and R32/R1270 were selected based on the acceptable efficiency and availability. Further investigation of the pool boiling performance of the two mixtures with various mass fractions was conducted. The results showed that the heat transfer coefficient deteriorated as the temperature glide and the vapor–liquid fraction difference became larger, and increased with the increasing of the vapor pressure and thermal conductivity. Meanwhile, the heat transfer coefficient of the two mixtures did not deteriorate at the mass fraction of R32 near 70 wt%, where the near-azeotropic mixtures were formed. The results show that the pool boiling heat transfer performances of R32/R290 (70/30 wt%) and R32/R1270 (70/30 wt%) were 2.23% lower and 8.67% higher than that of R410A, respectively, and R32/R1270 (70/30 wt%) has 9.3% higher performance than pure R32 at low heat flux. Six correlations were compared against the present data. None of the correlations can accurately predict both the R32/R290 and R32/R1270 mixtures. A modified correlation based on three of the six previous correlations was developed taking account the vapor–liquid fraction difference, temperature glide, heat flux, and system pressure. The prediction performances of the modified correlation were improved for both mixtures with the mean absolute deviation of 5.95 % and 6.58 % for R32/R290 and R32/R1270, respectively, and most of the data points within the deviation band of 15 %.

Performance and Exergy analysis of TurboJet and TurboFan configurations with Rotating Detonation Combustor

Conventional gas turbine is reaching its saturation level and further improvement in the cycle efficiency is possible through redesigning the cycle. One of the effective methods is to introduce a Pressure Gain Combustor (PGC) in place of the conventional deflagration combustor as PGC contributes to a considerable gain in thermal efficiency. Pulsed Detonation Combustor (PDC) and Rotating Detonation Combustor (RDC) are the two most prevalent combustor designs for pressure gain combustion. The major challenges of integrating PGCs to existing conventional cycles are the highly unsteady exhaust flow from PGC, high exhaust temperatures from PGC, potential back flow from combustor to compressor. As turbines are designed for much steadier flows, this unsteady exhaust flow and high temperature exhaust gas from PGC is challenging for the turbine of the cycle and its design. One of the solutions is to have an ejector between the PGC and turbine in order to reduce the flow fluctuations, flow velocity and flow temperature. In this work, different cycle layouts of Turbojet and Turbofan engines working with RDC are described. Low order RDC and ejector models are used in this paper. As the ejector is being used, the compressed air from the compressor is split for RDC, ejector, turbine blade cooling. The different cases for the compressed air split are also examined. The performance parameters of the engines are evaluated for different compressor pressure ratios, fan pressure ratios, bypass ratios. Finally, an exergy analysis is performed on all components.

Efficiency of Boiler and Steam Turbine for Power Plant Unit 2 PT. XYZ

PT. XYZ has an electric power capacity of 70 MW and began operating in 2014 during its operation there has been a decrease in power from 35 MW at the time of commissioning to 32 MW. This study investigates the impact of the air-fuel ratio (AFR) on the efficiency of a thermal system, focusing on the boiler, turbine, and overall thermal cycle efficiency. Variations in excess O2 in flue gas were examined at levels of 5.0%, 5.5%, and 6.0%. The results reveal that the boiler efficiency peaks at 5.0% excess O2 (73.50%), while an increase in excess O2 or AFR leads to a decrease in efficiency. Turbine efficiency remains relatively stable (74-76%) despite a slight decline with increased AFR. The thermal cycle efficiency reaches its maximum at an AFR of 13.61 (45.60%) but diminishes at higher AFR values.

Determining the exergy and energy efficiency of an organic Rankine cycle using fuzzy logic method

AbstractThe Organic Rankine Cycle (ORC) serves as a pivotal technology for energy conversion, harnessing high‐temperature organic liquids sourced from heat reservoirs to propel turbines and generate electricity. This process not only facilitates the conversion of heat into mechanical energy but also significantly mitigates environmental impacts. ORC stands out as the preferred technology for enhancing energy efficiency and leveraging low‐temperature resources optimally. With the advent of artificial intelligence, particularly fuzzy logic, these systems have witnessed integration, providing a robust solution to address uncertainties. Unlike traditional logic, which offers binary outcomes, fuzzy logic offers a more adaptable approach by accommodating uncertainty, thus enabling modeling of complex real‐world situations. In this study, utilizing the fuzzy logic method, we estimated the energy and exergy efficiency of the ORC, resulting in an impressive 90% estimation accuracy.

Thermodynamic and economic analyses of the biomass gasification Allam cycle integrated with compressed carbon energy storage

The Allam cycle is a novel oxy-fuel power system that has the potential to achieve efficient negative carbon emissions. Compressed carbon energy storage (CCES) technology could improve the stability of power plants. A biomass gasification Allam cycle combined with the CCES system is proposed and evaluated in this research. The energy efficiency of the Allam-CCES cycle during the charge and discharge time is 36.43 % and 39.45 %, respectively. The round trip efficiency (RTE) of the CCES system is 62.04 %. The exergy destruction of the Allam-CCES system is 317.02 MW. Economic analysis shows that the proposed system has a net present value of 447347.97 k$, implying benefits in economic performance. The total cost rate of the Allam-CCES system is 6959.63 $/h. The influence of the storage pressure on the CCES system is evaluated. The RTE drops from 64.55 % to 61.12 % as the high storage pressure rises. The variation of RTE has a crest when the low storage pressure is near critical pressure. The highest RTE is 90.71 % in the research range of low storage pressure. This paper could provide information on biomass gasification Allam cycle integrated with CCES technology, and offer insights to realize efficient and economic carbon emissions reduction.

Improving efficiency in green tea production time using lean manufacturing approach with value stream mapping: A case study at PT Candi Loka [Perbaikan efisiensi waktu produksi teh hijau menggunakan pendekatan produksi ramping dengan value stream mapping: Studi kasus di PT Candi Loka

Green tea production activities at PT Candi Loka indicated a time-consuming, which caused process efficiency to be less than optimal. Process efficiency improvements must be made to increase company competitiveness and consumer satisfaction. This research aimed to analyze the efficiency of green tea production time at PT Candi Loka by identifying the processing time required in each production activity, including the time consumption and formulating recommendations for improvement using a lean manufacturing approach using the VSM (Value Stream Mapping) method. There were 30 activities in 6 processes consisting of receiving raw materials, withering, rolling, drying, and packaging. Identification of value streams using the PAM (Process Activity Mapping) tool produced 9 Value added (VA) activities, 19 Necessary but Non-Value Added (NNVA) activities, and 2 Non-Value Added (NVA) activities in the form of delays in the withering and drying processes. In the current state map analysis, the production lead time value was 315.286 seconds. Recommended improvements to eliminate delays in the withering process were to set up the rotary panner machine earlier and increase the number of supervisors, while to eliminate delays in the drying process were to implement a piece rate system. Increasing efficiency was also carried out by improving NNVA activities by adding weighbridge facilities and using a conveyor system. The future state map proposed by implementing recommended improvements resulted in an increase in production time efficiency to 222.356 seconds and an increase in the process cycle efficiency value from 58.95% to 84.85%.

Auxiliary Heat System Design and Off-Design Performance Optimization of OTEC Radial Inflow Turbine

In this paper, solar energy is used as the auxiliary heat source of the ocean thermal energy radial inflow turbine, and the thermodynamic model of the circulation system is established. In addition, the ejector is introduced into the ocean thermal power generation system, and the process simulation is carried out using Aspen Plus V12. To address performance attenuation of the radial turbine under varying working conditions, shape optimization of a 30 kW OTEC radial turbine was conducted. Finally, the off-design performance variation in the radial inflow turbine is analyzed in the presence of a solar auxiliary heat source. The results show that the use of an auxiliary heat source can effectively improve the cycle efficiency of the system and is also conducive to the stable operation of the radial turbine. Under the condition of auxiliary heat source, the system cycle efficiency is increased by 2.269%.

Protonated covalent organic frameworks for green and effective recovery of Au(I) from thiosulfate solutions: Performance, DFT calculations, and mechanism insights

The recovery of Au(I) from thiosulfate leaching systems is important to ensure the sustainable use of strategic metal resources. In this study, two ionic covalent-organic frameworks (iCOFs), Tmp-Tpa COF-Cl and Tmp-Tpa COF-SO4, were synthesized through a post-modification strategy guided by theoretical calculations. Acid modification redistributed the surface charge of Tmp-Tpa COF due to the protonation of nitrogen atoms, which enabled the efficient and selective recovery of Au(I) from a thiosulfate solution. The Au(I) adsorption capacities of Tmp-Tpa COF-Cl and Tmp-Tpa COF-SO4 were 69.8 mg/g and 71.3 mg/g, respectively, which were significantly higher than those of previously reported materials. Adsorption equilibrium isotherms and kinetic studies revealed that the adsorption of Au(I) onto iCOFs conformed to the Langmuir and quasi-second-order kinetics model, showing that Au(I) underwent uniform monolayer chemisorption on the surface of the iCOFs. X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared (FTIR) spectroscopy and density functional theory (DFT) calculations indicated that the adsorption of Au(I) onto Tmp-Tpa COF-Cl and Tmp-Tpa COF-SO4 was mainly because acid modification converted –C = N to –C = NH+-, which enhanced the strength of electrostatic attraction and coordination with Au(S2O3)23− complexes. Acidic thiourea rapidly eluted Au(I) adsorbed onto the iCOFs and simultaneously regenerated Tmp-Tpa COF-Cl. Even during the fifth adsorption/desorption cycle, the adsorption and desorption efficiencies of the iCOF still reached 86.6 % and 97.7 %, respectively. In addition, Tmp-Tpa COF prepared by Knoevenagel condensation was inexpensive (less than $50/kg) and did not require the use of organic solvents, enabling large-scale green production. This work provides an innovative method for the efficient, selective, and high-capacity recovery of gold from thiosulfate leachate.

Tổng hợp vật liệu LiNi0,9Mn0,05Co0,05O2 bằng phương pháp phản ứng pha rắn (NMC9.5.5-PR) ứng dụng chế tạo pin ion liti

Nickel-manganese-cobalt (NMC) transition metal oxide-based layered structural materials are evaluated a promising material for applications as cathode in lithium-ion batteries. In this study, we have successfully synthesized nickel-rich NMC material LiNi0.9Mn0.05Co0.05O2 by solid-state reaction method (NMC9.5.5- PR). The CR2032-type lithium-ion battery is also successfully fabricated from NMC material to serve the study of electrochemical properties. The NMC9.5.5-PR material exhibits outstanding discharge specific capacity when providing a maximum specific capacity of up to 212.4 mAh/g at a current density of 10 mA/g. However, the cycle efficiency survey results show that the NMC9.5.5-PR material has some disadvantages (only maintaining 81.6% of the discharge specific capacity after 50 continuous charge-discharge cycles at current density of 10 mA/g). These electrochemical properties indicate that it is necessary to further improve the cyclic efficiency of NMC9.5.5-PR material but preserving its outstanding electrical energy storage capacity. Successfully accomplishing this goal, we believe that NMC-9.5.5-PR or a material based on NMC9.5.5-PR will be one of the suitable materials to fabricate positive electrodes used in lithium-ion batteries.

Performance assessment of single-sided operation in a high-temperature latent heat storage system under fault conditions during charging and discharging

As the high-temperature latent heat storage (LHS) market continues to expand, ensuring its safe and stable operation is paramount for facilitating its rapid development. In specific operational scenarios and instances of failures, large-scale integrated LHS systems may operate with either single or partial sets of heat exchange tubes. However, a notable research gap exists in the comprehensive exploration of the impact of partial operational conditions on the thermal performance of LHS systems. Consequently, this study conducted experiments involving both- and single-sided charging and discharging using a cylindrical high-temperature LHS system equipped with two sets of heat exchange tubes. To comprehend the ramifications of single-sided operation on temperature distribution across both active and inactive sides, as well as its influence on charging/discharging power and accumulated stored/released energy on the active side. The analysis of phase change material (PCM) temperature distribution revealed that single-sided charging significantly influenced the inactive side, while single-sided discharging exhibited a comparatively minor impact on the inactive side. As PCM melted during charging, temperature disparities diminished due to natural convection, while non-uniform temperature persisted in unmelted PCM. Examination of the PCM liquidus indicated that the metal heat exchange tube enhanced heat transfer on the inactive side, resulting in substantial PCM melting during charging. However, the heat transfer effect of metal heat exchange tubes during discharging was insignificant, leading to a considerable amount of liquid PCM on the inactive side after discharging. The total heat storage for both-sided charging was 1002.71 MJ, whereas, for single-sided charging using two tubes, it was 1074.42 MJ and 1000.60 MJ, respectively. Correspondingly, during discharging, the average powers were 682.74 MJ, 543.62 MJ, and 538.11 MJ, respectively. The cycle efficiency for the both-sided operation was 68.09 %, while those for single-sided operations of two tubes were 50.6 % and 53.78 %, respectively. The reduced cycle efficiencies of single-sided operations were attributed to prolonged charging and discharging durations and the presence of more liquid PCM on the inactive side after discharging.

Performance analysis of combining solid oxide electrolysis cell hydrogen production and marine hydrogen compressed natural gas engine system

Natural gas holds promise as an alternative energy source for ships, and its combustion blended with hydrogen can achieve better beneficial of energy saving and emission reduction. Nevertheless, the current challenges in hydrogen, characterized by its high cost and difficulties in storage and transportation, hinder its application in maritime technology. To address the issue, this study proposes a system that integrates a marine hydrogen compressed natural gas (HCNG) engine, a supercritical carbon dioxide Brayton cycle (SCBC), and a solid oxide electrolysis cell (SOEC). In this system, SCBC is capable of recovering waste heat for electricity generation, while SOEC serves as an energy storage device to adjust engine load and enhance fuel economy. The generated hydrogen can be utilized as a source of hydrogen in HCNG fuel, thereby improving engine performance and reducing pollutant emissions. Various system numerical simulation schemes with different engine hydrogen volume fractions were studied. The results show that the electrical efficiency of SOEC is improved by 17.86% by heating the feed stream with engine exhaust gas. In addition, the hydrogen fraction in which SOEC can act as a complete hydrogen source ranges from 30% to 40%. The results of the sensitivity analysis show that the cycle efficiency reaches a peak of 31.5% at a compressor outlet pressure of 16 MPa, while the efficiency of the whole system reaches a maximum of 50.8% at 21 MPa. The optimal operating temperature for the SOEC falls within the range of 650–700 °C for the 30, 40 HCNG schemes, and between 750 and 800 °C for the 50, 60 HCNG schemes.

A review of methane-driven two-step thermochemical cycle hydrogen production

Solar thermochemical cycling is a promising approach to utilizing solar energy to produce H2 and CO, which can be further synthesized into liquid fuels via Fischer-Tropsch reactions, making storage and transportation easier. Despite the potential high theoretical efficiency, factors such as the high temperature and low oxygen partial pressure required for the reduction restrict the large-scale application of this technology. In the near-to-medium term, in order to accelerate the popularization and application of this technology, according to Le Chatelier's principle, the assisted reduction of methane can greatly reduce the demand for high-temperature materials and ultra-low oxygen partial pressure. However, the addition of methane will also bring additional challenges, such as carbon emissions and carbon deposition. Reducing the influence of factors such as material sintering and irreversible loss on system efficiency in the experiment will be essential for the development of this technology. This paper focuses on the methane-driven two-step thermochemical cycle hydrogen production process, summarizes its reaction mechanism, thermodynamic analysis, kinetic analysis, oxygen carrier material doping, and experimental research in detail, and comprehensively analyzes the effect of material properties and irreversible loss on the system. According to thermodynamic and kinetic analysis, rational selection and doping of metal oxygen carrier materials can effectively reduce the reaction temperature, improve gas production rates, and enhance structural stability. Analyzing and trying to reduce various irreversible losses of the system, such as reradiation energy loss, conduction energy loss, etc., and taking appropriate heat recovery measures will help to improve the system efficiency of the actual cycle. This paper would be valuable for the development of this technology and for achieving the goal of carbon neutrality.

Identifikasi Non-Added Value Activity Dalam Proses Pemeriksaan Substantif Permohonan Paten Menggunakan Value Stream Mapping

The process of substantive patent examination which is complicated and takes a long time is one of the reasons the inventor is "reluctant" to apply for a patent on his invention. This research was conducted using the Current State Value Stream Mapping (CSVSM) method, which began with the creation of a process flow map with the cycle time of each activity. It is known that most of the activities are value added activities. However, there is 1 activity that is required but not added value, namely the activity of verifying the technical field of application documents; and 1 non-value-added activity, namely initialing the Patent Granting letter. The number of waiting/delaying incidents is a waste in the process of substantive examination of patent applications caused by: (a) employees generally do double work; and (b) the absence of SOPs in each sub-process/sub-activity in the process of substantive examination of patent applications. Proposed improvements are submitted in the Future State Value Stream Mapping (FSVSM). As a result, lead-time can be reduced to 11 days, which was originally 26 days; and Process Cycle Efficiency which was originally 19.23% increased to 45.45%

Design, Multi-Point Optimization, and Analysis of Diffusive Stator Vanes to Enable Turbine Integration Into Rotating Detonation Engines

Abstract Pressure gain combustion is considered a possible path toward improved thermal cycle efficiency and reduced carbon emissions. However, ad hoc turbine designs are required to maximize the thermodynamic potential; the new turbomachinery should be suited for the oscillations in flow conditions generated by the detonation combustor, which are very different from conventional gas turbines. This paper investigates the design, optimization, and analysis of diffusive stator vanes operating under large inlet flow angles in the high-subsonic regime. First, the design methodology is outlined, focusing on the geometric requirements to ingest high Mach number flow and the parametric modeling of the endwall and the 3D vane pressure and suction sides. Then, the impact of the inlet flow angle on the flow field and vane design is studied through a multi-point, multi-objective optimization with three different inlet angles, performed using steady Reynolds-averaged Navier–Stokes simulations. Remarkable reductions in pressure loss and stator-induced rotor forcing are attained while maintaining an extensive operating envelope and high flow turning. Moreover, several design guidelines are provided based on the analysis of the optimized geometries. Finally, the effectiveness of the proposed methodology is verified with an unsteady assessment of the baseline and optimized vane designs.

Energy efficiency as an accelerator to environmental and operational performance

As oil and gas operators continue to enhance and start implementing their plans to meet their regulators’ and customers’ net-zero related demands, the industry should not overlook those low-hanging fruit that will bear results in the short term and, if done well, also contribute to long-term objectives. An effective approach to energy management will contribute to environmental, operational and financial outcomes, by addressing resource scarcity and price volatility, delivering on licence-to-operate considerations, complying with regulations, and delivering a competitive advantage through greater efficiency and enhanced reputation. Key considerations are as follows. Data quality: fuel, power, steam, condensate balances will highlight data gaps and inconsistencies. Energy usage: inefficiencies in operations such as boilers, turbines, as well as systemic issues, such as cycle efficiency and steam and condensate losses, can be identified. Emissions monitoring and reporting: clear and consistent data about fuel and power consumption directly feeds into greenhouse gas corporate reporting schemes. Quality assurance of monitoring and reporting processes: review and challenge dashboards and reports for completeness, accuracy and clarity. Management operating system: redesign management processes to improve workflows and optimise operations. Loss accounting: Production and Energy Loss Accounting (PELA) improves staff collaboration and effectively tackles hidden losses. In this paper, dss+ will share how, using a mix of operational efficiencies and capex, an integrated oil and gas company active in 30 countries identified potential to reduce its emissions by 38 m tonnes of CO2 leading to over US$6 m in savings per annum over 4 years for just four of its assets.