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Due to the growing number of diverse power systems disruptions, including extreme weather events, technical factors, and human factors, assessing and quantifying the resilience of electric power subsystems has become an indispensable step to develop an efficient strategic plan to enhance the resilience and reliability of these systems and to endure the diverse interruptions. In this study, factors and sub-factors that may have either direct or indirect impact on the resilience of biomass-based combined heat and power systems are identified, and the interdependencies among them are determined as well. A Bayesian network model is implemented to quantify the resilience of a bCHP system, and the results are analyzed by applying three different techniques, which are sensitivity analysis, forward propagation analysis, and backward propagation analysis.

[pt] O concreto armado (CA) tem sido amplamente utilizado em construções civis durante quase dois séculos devido a sua versatilidade e relativamente baixo custobenefício quando comparado com outros sistemas estruturais. É, notoriamente, o sistema mais adotado na construção de obras estratégicas e de infraestrutura. No entanto, as construções de CA estão em constante deterioração. Sobretudo nas últimas décadas, atenção especial vem sendo dada à influência de cenários dinâmicos nesse tipo de sistema estrutural devido à intrínseca baixa resistência à tração e fragilidade do concreto, que promovem extensos horizontes de fissuração na ocorrência desses eventos. A presente investigação dedicou-se à avaliação de duas variações de compósitos cimentícios de comportamento strain-hardening (SHCC) como material de reforço para melhorar a resistência ao impacto de edifícios existentes, em especial membros estruturais com falhas críticas por cisalhamento. SHCC é uma classe relativamente nova de compósito cimentício reforçado com fibras, em geral microfibras sintéticas com fração volumétrica média de 2 %. Estudos recentes já demonstraram que este compósito é capaz de deformarse substancialmente quando submetido à tração direta (até 6% dependendo da dosagem) durante o estágio de múltipla-fissuração, enquanto sustenta uma abertura de fissura de até 100 μm. O SHCC parece especialmente adequado para resistir a impactos de alta velocidade devido ao número relevante de superfícies que se formam durante a sua fase de deformação, uma vez que a grande quantidade de superfícies que são formadas durante o processo de múltipla-fissuração representa uma perspectiva elevada de dissipação de energia sem reduzir a capacidade de carregamento. Dois tipos de SHCC de resistência normal foram escolhidos para serem avaliados nesta investigação. Os compósitos diferenciavam-se principalmente no tipo de fibra de reforço: PVA e UHMWPE. Como os elementos estruturais incorporados em estruturas estão frequentemente sujeitos a estados multiaxiais de tensão, para avaliar o potencial de SHCC como material de reforço, ensaios combinados de torção e tensão foram desenvolvidos. Tais resultados permitiram o aprofundamento da compreensão do desempenho mecânico dos SHCC em análise sob cisalhamento, ao mesmo tempo que permitem a combinação desses esforços com tensões normais de tração. Em seguida, o potencial efetivo do SHCC no melhoramento da resistência e resiliência de elementos estruturais existentes a cargas de impacto foi investigado por um extenso programa experimental que contou com 24 vigas de escala real. Os parâmetros variados foram: (i) o tipo de SHCC; (ii) a configuração de reforço interno (espécimes com e sem estribos); (iii) a energia de impacto (que variou entre 2,1 kJ e 6,4 kJ, correspondendo a velocidades aproximadas de 17 m/s a 30 m/s, respectivamente). Os resultados foram avaliados em termos da resposta mecânica, padrões de fissuração, e análise modal. Foi demonstrado que ambos os tipos de SHCC contribuíram para a melhora da resistência ao impacto das vigas de CA reforçadas, melhorando expressivamente a resposta dinâmica residual e de estabilidade, enquanto contribuíram efetivamente para segurança de usuários ao propiciar uma redução substancial de detritos desprendidos durante os testes. O SHCC reforçado com fibras de UHMWPE mostrou-se menos sensível à presença ou ausência de estribos, sugerindo que esse compósito seja o mais adequado para aplicações de reforço de cisalhamento em cenários dinâmicos onde existe uma deficiência, ou incerteza, sobre o reforço transversal interno dos membros existentes. / [en] Reinforced concrete (RC) has been widely used in civil constructions for almost two centuries due to its versatility and relatively low cost-effectiveness ratio when compared with other structural systems. It is notably the preferred material for the construction of strategic infrastructures. However, RC constructions are in constant deterioration. Special attention had been given in the last decades to the influence of dynamic scenarios on RC structures due to concrete s inherent low tensile strength and brittle nature, which promotes intense cracking during these events. The present research focused on the assessment of two variations of strainhardening cementitious composites (SHCC) as strengthening material to improve the impact resistance of existing buildings, moreover structural members with critical shear failure. SHCC is a somewhat new class of fiber-reinforced composite reinforced with synthetic microfibers with an average content of 2 % in volume. Previous research studies already demonstrated that this composite is able to yield substantial deformations under tension (up to 6 % depending on the dosage) during its multiple-cracking phase, while enduring a crack-width limit of 100 μm. SHCC seems especially appropriate to withstand high-velocity impacts due to the relevant number of surfaces that are formed during its deformation phase since it represents a high perspective of energy dissipation without reducing load-bearing capacity. Two types of normal-strength SHCC were chosen to be assessed in this research. The composites differed mainly in the type of reinforcing fiber: PVA, and UHMWPE. As structural members embodied in structures are often subjected to multiaxial stress states, to evaluate SHCC´s potential as a strengthening material, combined torsion and tension tests were developed. These tests deepen the understanding of SHCC s mechanical performance under shear, while also enabled the combination with normal stresses. Then, SHCC s actual potential to improve the impact resistance and afterlife of existing structural members was investigated during an extensive experimental program that counted with 24 real-scale beams. The varied parameters were: (i) the type of SHCC; (ii) the internal reinforcement configuration (specimens with, and without stirrups); (iii) the impact energy (which was varied between 2.1 kJ and 6.4 kJ, corresponding to approximated velocities of 17 m/s to 30 m/s, respectively). The results were assessed in terms of their mechanical response, cracking patterns, and modal analysis. It was demonstrated that both types of composites improved the impact resistance of the strengthened RC members, outstandingly improving the impact safety with regards to residual dynamic response and stability while presenting a substantial reduction of spalling and scabbing material. The SHCC produced with UHMWPE fibers appeared to be less sensitive to the presence or absence of stirrups, posing as more suitable alternative for shear strengthening applications within dynamic scenarios where there is a deficient, or even uncertainty, about the internal transversal reinforcement of the existing members.

Stormwater sewer infrastructure is at risk due to ageing, structural deterioration, population growth, and climate change. Since the consequences of the sewer system failure can adversely impact the community safety, environment and economy, a resilient infrastructure system is of essential importance. However, limited reinvestment budget and insufficient asset management practices impact the rehabilitation of urban sewerage systems. Therefore, an effective and efficient rehabilitation plan is needed to help proper investment decisions. An effective rehabilitation plan will maximize hydraulic performance while minimizing the overall failure risk within a limited budget. The current study aims to address this issue through designing a risk-informed methodology in three steps. First, the hydraulic risk index (obtained using the SWMM model) was combined with the ageing pipe index. The framework uses multi-objective optimization technique to generate solutions under specific sewerage conditions. We named this new framework as Hydraulics and Risk Combined Model (HRCM). Several scenarios including high hydraulic risk, high ageing risk, hydraulic risk and ageing risk (combined problems), and limited budget problems, are used to test the performance of the proposed methodology. The results show that the proposed model could provide a satisfactory solution. Then, in order to increase the calculation speed and improve the accuracy, sensitivity and cost-effectiveness analyses were also conducted for the proposed methodology with different algorithms. The results show that different algorithms offer various benefits. A new calculation method was offered by combining the advantages of the previous methods. Finally, a new optimization method named Phenotype Searching Method, which was enlightened by sexual selection processes, was offered. This method can enhance the selection processes to specific phenotypes (pipes) so that it can increase the convergence speed and increase the performance of the HRCM model.

Abstract The Effects of a Combined Supplementation of Creatine and Sodium Bicarbonate on Repeated Sprint Performance James Jeremy Barber There is well-established research that suggests both creatine and sodium bicarbonate are effective ergogenic aids. However, only one published study has examined the combined effects of creatine and sodium bicarbonate. The primary purpose of this study was to determine if a combined supplementation of creatine monohydrate and sodium bicarbonate would further enhance the well-documented effects of creatine supplementation alone on repeated sprint performance. Thirteen healthy and fit males (Mean age = 21.15 ± 0.65 years and mean VO2 max = 66.72 ± 5.78) participated in this experimental study using a double-blinded crossover study design in which each subject was used as his own control. All subjects completed 3 conditions, followed by a 3-week washout period between each condition: 1) Placebo (Pl; 5 g maltodextrin + 0.5 g/kg maltodextrin), 2) Creatine (Cr; 5 g + 0.5 g/kg maltodextrin), and 3) Creatine plus sodium bicarbonate (Cr+Sb; 5g + 0.5 g/kg sodium bicarbonate). Each condition was a 2-day supplementation. In the morning after each supplementation, peak power, RPP, mean power, RMP, fatigue index, and perceptions of fatigue and GI distress were assessed during six 10-second repeated Wingate tests. Blood bicarbonate, pH, and lactate were measured 5 minutes before testing and immediately after the last Wingate sprint. The main findings were; 1) Cr+Sb produced 7% greater relative peak power and 4.6% greater peak power values than placebo, and 2) Cr+Sb demonstrated the greatest attenuation of decline in relative peak power over six repeated sprints. However, in contrast to our hypotheses, no benefits from either supplementation were observed for relative mean power, fatigue index, and perception of fatigue. Considering that this current study found benefits from combining creatine and sodium bicarbonate, it suggests that combining the supplements may improve repeated sprint performance. Future research on a greater sample size, a specific athletic population, various exercise modes, and comparing results with a sodium bicarbonate alone supplementation would be beneficial in determining if this combined supplementation is worthwhile.

Yes / Construction and demolition waste (CDW) has reached severe environmental and economic dimensions due to its large volume among all solid waste, highlighting the importance of local actions to manage, recycle, and reuse CDW. Ductile demountable connections are necessary to disassemble and reuse the concrete structural members and fast assembly of precast structures in seismic regions without generating waste. In this study, the seismic performance of CDW-based reinforced geopolymer concrete columns has been investigated. Six ½ scaled columns (half of which were demountable and the other half monolithic) were experimentally tested under reversed cyclic lateral displacement excursions, considering three different levels of constant axial loading to determine failure mechanisms, load–displacement responses, ductilities, energy dissipation capacities, stiffness degradation relations, and curvature distributions. The obtained test results were used to determine the performance of CDWbased geopolymer concrete columns and compare the performances of the demountable connection with the monolithic connection. The test results showed that the novel demountable connection for precast concrete frames exhibited better seismic performance in terms of maximum lateral load capacity, initial stiffness, energy dissipation capacity, and maximum curvature than their monolithic counterparts. Besides, increasing the axial compression ratio on the columns caused an increase in lateral load capacity, energy dissipation capacity, energy dissipation ratio, and initial curvature stiffness; however, it decreased the ductility. Finally, the capacity predictions of current codes, i.e., TS500 and ACI318, were conservative when compared with experimental results. / This publication is a part of doctoral dissertation work by the first author in the Academic Program of Civil Engineering, Institute of Science, Hacettepe University. The authors gratefully acknowledge the financial assistance of the European Union’s Horizon 2020 research and innovation program under grant agreement No: 869336, ICEBERG (Innovative Circular Economy Based solutions demonstrating the Efficient recovery of valuable material Resources from the Generation of representative End-of-Life building material). This work was also supported by Newton Prize 2020. The fifth and seventh authors acknowledge the financial support received from the European Union’s Horizon 2020 research and innovation program under the Marie SkłodowskaCurie grant agreement No 894100. / The full-text of this article will be released for public view at the end of the publisher embargo on 4th Oct 2024.

Worldwide concern on reducing global warming consequences has motivated the development of power generation technologies to move towards renewable and sustainable energy. The process takes time and currently, a significant percentage of the world’s electricity systems are driven by fossil fuels. The transition phase from fossil fuel to renewable technology has allowed the combined cycle gas power plant to play an essential role in our global energy mix. This investigation aims to develop scenarios to improve its performance and reduce the carbon footprint during its operation. A baseline scenario of the natural gas combined cycle has been developed using Aspen Hysys software, and the simulation performance is validated with ASME PTC 4-4. The analytical validation results in a 1.13% difference in air and fuel flow rate of 642.95 kg/s compared with 650.28 kg/s as simulation input. Four scenarios are developed following the baseline scenario: seawater cooling and intercooling with LNG cold energy utilization, carbon capture, and hydrogen blending. Those scenarios are compared with three key performance indicators such as system efficiency (%), levelized cost of electricity (USD/MWh), and specific carbon dioxide emissions (gr-CO2/kWh). The analysis shows that sea water cooling with LNG cold energy achieves the highest efficiency of 56.46%, a 0.12% increase compared with the baseline scenario. Hydrogen blending with natural gas achieves the lowest LCOE and specific carbon dioxide footprint of 46.97 USD/MWh and 351.23 gr-CO2/kWh, respectively. The reduction of 12.58 kTon annual carbon dioxide is achieved by implementing 5% hydrogen blending by volume into the combined cycle power generation system. / Världsomfattande oro att minska konsekvenserna av den globala uppvärmningen har motiverat kraftgenereringsteknik att gå mot förnybar och hållbar energiutveckling. Processen tar tid och förnuvarande drivs en betydande andel av världens elsystem av fossila bränslen. Övergångsfasen från fossilt bränsle till förnybar teknik har gjort det möjligt för kombikraftverk att spela en viktig roll i vår globala energimix. Denna rapport syftar till att utveckla scenarier för att förbättra dess prestanda och minska koldioxidavtrycket under dess drift. Ett utgångsscenario för naturgasens kombinerade cykel har utvecklats med hjälp av Aspen Hysys programvara, och simuleringsprestandan är validerad med ASME PTC 4-4. Den analytiska valideringen resulterar i en skillnad på 1,13 % i luft- och bränsleflöde på 642,95 kg/s jämfört med 650,28 kg/s som simuleringsindata. Fyra scenarier utvecklas efter baslinjescenariot: havsvattenkylning och mellankylning med LNG kall energianvändning, kolavskiljning och väteblandning. Dessa scenarier jämförs med tre nyckeltal som systemeffektivitet (%), utjämnad kostnad för el (USD/MWh) och specifika koldioxidutsläpp (gr-CO2/kWh). Analysen visar att havsvattenkylning med LNG kall energi uppnår den största verkningsgraden på 56,46 %, en ökning med 0,12 % jämfört med utgångsscenariot. Vätgasblandning med naturgas uppnår lägsta LCOE och specifika koldioxidavtryck på 46,97 USD/MWh respektive 351,23 gr-CO2/kWh. Minskningen av 12,58 kTon årlig koldioxid uppnås genom att implementera 5 % vätgasblandning i volym i det kombinerade kraftgenereringssystemet.

The study aims to investigate an appropriate wastewater treatment process to treat domestic wastewater in Hanoi City which contain low-strength for COD (120-200 mg/L) but high in nitrogen content (10-40 mg/L). A lab scale anoxic-oxic system with a hollow fiber-Membrane Separation Bioreactor was operated at a flow rate of 5-10 L/h over a period of 150 days. The reactor was operated at different sludge recirculation rates. The MBR maintained relatively constant transmembrane pressure. During 150 days of reactor operation, treated water quality have COD of around 20 mg/L, NH4-N of less than 1 mg/L, NO3-N of less than 5 mg/L. The system shows good and stable efficiency for organic matter and nitrogen removal without adding an external carbon source and coagulants. The results based on the study indicated that the proposed process configuration has potential to treat the low-strength wastewater in Hanoi. / Mục tiêu của nghiên cứu là đề xuất được một công nghệ hiệu quả và phù hợp để xử lý nước thải sinh họat ở các đô thị của Việt nam, là loại nước thải được thu gom từ hệ thống thoát nước chung có nồng độ chất hữu cơ thấp (COD 120-200 mg/l) nhưng hàm lượng chất dinh dưỡng như Nitơ, Phốt pho khá cao (T-N: 10-40 mg/L). Chúng tôi đã nghiên cứu và vận hành chạy thử mô hình xử lý sinh học yếm khí - kỵ khí (AO) kết hợp với màng vi lọc ở quy mô mô hình phòng thí nghiệm (công suất 5-10 L/h) ở các chế độ công suất bùn tuần hoàn khác nhau. Kết quả xử lý trong thời gian 5 tháng vận hành mô hình cho thấy chất lượng nước thải sau xử lý có hàm lượng COD nhỏ hơn 20 mg/L, NH4-N nhỏ hơn 1 mg/L, NO3-N nhỏ hơn 5 mg/L. Hiệu suất xử lý chất hữu cơ và chất dinh dưỡng rất ổn định và hệ thống không phải sử dụng các nguồn bổ sung chất hữu cơ hay các hóa chất trợ lắng như các công nghệ đang áp dụng. Kết quả cho thấy công nghệ AO kết hợp màng vi lọc có khả năng áp dụng thực tế, phù hợp với những nơi có quỹ đất nhỏ, chất lượng nước sau xử lý rất cao có thể phục vụ cho mục đích tái sử dụng.

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