Enhancement Of Production Research Articles

Sustainable transformation: Unlocking energy positivity in municipal wastewater treatment through innovative advanced primary treatment configurations for maximum solids separation

Motivated by the growing need for sustainable wastewater management and environmentally friendly solutions for wastewater treatment in the future, the current study explored all possible configurations for advanced primary treatment (APT) on a long-term assessment, encompassing extensive lab and pilot-scale studies for removing particulate organic carbon (POC) in municipal wastewater treatment plants (WWTPs). This study primarily aimed to have a comprehensive insight into various APT configurations for municipal wastewater treatment. The physical-APT method employed a microsieve (MS) with an adjustable drum to 20 and 100 µm mesh. The flocculation process was integrated with one or two consecutive sedimentation tanks to simulate the chemical-APT method. Lastly, the chemical-physical-APT (ChPh-APT) approach was emulated by combining the flocculation process with the MS technique. Considering the best-case scenario to remove utmost POC, the results illuminated a substantial potential for biogas production enhancement by around 85 % (from 1.3 to 2.4 g (cap. d)-1 converted chemical oxygen demand (COD) to biogas) through ChPh-APT configuration. Furthermore, estimations showed that maximum POC removal can significantly reduce energy demand from 42 to 28 kWh (cap. a)-1 while simultaneously increasing green electricity generation from 11 to 33 kWh (cap. a)-1. This transformation will eliminate dependency on external energy sources and significantly increase by-product generation like volatile fatty acids (VFA), Polyhydroxyalkanoate (PHA), and hydrogen (H2) in the concept of a biorefinery. The possible increase in the production of H2 can be from roughly 32 to 58 L (cap. d)-1, PHA recovery from 1.3 to 2.4 g (cap. d)-1, and VFAs from about 12 to 22 g (cap. d)-1. Consequently, this transformation will enhance the efficiency of municipal WWTPs and turn them into energy-positive, sustainable, and resource-recovery entities.

IMBA: IoT-Mist Bat-Inspired Algorithm for Optimising Resource Allocation in IoT Networks

The advent of the Internet of Things (IoT) has revolutionised our interaction with the environment, facilitating seamless connections among sensors, actuators, and humans. Efficient task scheduling stands as a cornerstone in maximising resource utilisation and ensuring timely task execution in IoT systems. The implementation of efficient task scheduling methodologies can yield substantial enhancements in productivity and cost-effectiveness for IoT infrastructures. To that end, this paper presents the IoT-mist bat-inspired algorithm (IMBA), designed specifically to optimise resource allocation in IoT environments. IMBA’s efficacy lies in its ability to elevate user service quality through enhancements in task completion rates, load distribution, network utilisation, processing time, and power efficiency. Through comparative analysis, IMBA demonstrates superiority over traditional methods, such as fuzzy logic and round-robin algorithms, across all performance metrics.

StresSense: Real-Time detection of stress-displaying behaviors

BackgroundWrist-worn gadgets like smartphones are ideal for unobtrusively gathering user data, in various fields such as health and fitness monitoring, communication, and productivity enhancement. They seamlessly integrate into users' daily lives, providing valuable insights and features without the need for constant attention or disruption. In sensitive domains like mental health, these devices provide user-friendly, privacy-protected means of diagnosis and treatment, offering a secure and cost-effective avenue for seeking help. ObjectivesThis study addresses the limitations of traditional mental health assessment techniques, such as intrusive sensing and subjective self-reporting, by harnessing the unobtrusive data collection capabilities of smartphones. Equipped with accelerometers and other sensors, these devices offer a novel approach to mental health research. Our objective was to develop methods for real-time detection of stress and boredom behavior markers using smart devices and machine learning algorithms. MethodologyBy leveraging data from accelerometers (A), gyroscopes (G), and magnetometers (M), we compiled a dataset indicative of stress-related behaviors and trained various machine-learning models for predictive accuracy. The methodology involved collecting data from motion sensors (A, G, and M) on the dominant arm's wrist-worn smartphone, followed by data preprocessing, transformation from time series format, and training a Deep Neural Network (DNN) model for activity recognition. FindingsRemarkably, the DNN achieved an accuracy of 93.50% on test data, outperforming traditional and ensemble machine learning methods across different window sizes, and demonstrated real-time accuracy of 77.78%, validating its practical application. ConclusionIn conclusion, this research presents a novel dataset for detecting stress and boredom behaviors using smartphones, reducing reliance on costly devices and offering a more objective assessment. It also proposes a DNN-based method for wrist-worn devices to accurately identify complex activities associated with stress and boredom, with benefits in terms of privacy and user convenience. This advancement represents a significant contribution to the field of mental health research, providing a less intrusive and more user-friendly approach to monitoring mental well-being.

Public--Private Cooperation Funding Juxtaposed of University--Community Engagement in Europe: Systematic Review

This article explores the utilization of public–private funding models in European universities and its implications for community empowerment initiatives, particularly University–Community Engagement (UCE) projects. A systematic literature review (SLR) was conducted using the Scopus database, screening 50 articles relating to public–private funding models in European universities. The study reveals that while public–private funding models have gained traction in the academic sphere, they primarily focus on supporting applied science research projects. In contrast, the funding of projects solely oriented toward community empowerment remains limited, with only one article addressing this potential. The findings highlight the challenges associated with employing public–private funding for UCE projects with a strong emphasis on community empowerment. Public–private funding, typically sourced from industry partners, tends to prioritize product innovations and productivity enhancements, posing a mismatch with the social justice-oriented nature of UCE. This discrepancy underscores a significant research gap in UCE and calls for innovative approaches to develop supportive funding frameworks that can effectively sustain UCE initiatives.
 Keywords: public–private funding, university–community engagement, European University

Estimating enhanced fish production on restored shellfish reefs using automated data collection from underwater videos

Abstract Shellfish reefs across the world have been heavily degraded by mechanical harvesting, disease and declining water quality. In southern Australia, where substantial losses have occurred, government and non‐government efforts to restore functioning reefs are now underway with a strong focus on enhancing fish productivity. However, the capacity of these restored reefs to enhance fish production remains unknown, hampering estimates of return on investment. We quantify the density differences of newly recruited juvenile fish and other nekton on these restored reefs, relative to those on unrestored, unstructured habitat. Fish were surveyed at three paired reef‐unstructured locations using 169 unbaited stereo video deployments during three periods over 12 months (2022–2023). We used automation software, FishID, to automatically identify, size and count fish in videos. We subsequently applied known growth and mortality parameters to model enhancement of fish productivity. Sixteen species occurred as new recruits, with all but two found at higher densities on reefs than unstructured habitat. Enhancement of fish production from subtidal restored shellfish reefs from a single year's cohort is estimated to be, on average, 6186 kg ha−1 year−1 (SD 1802) after enough time has elapsed for all species to have matured. Species harvested commercially or recreationally contributed 98% of that production (6083 kg ha−1 year−1, SD 1797). Enhancement varied greatly among locations, ranging from 12,738 kg ha−1 year−1 (SD 2894), which is the highest yet recorded anywhere, to 1.4 kg ha−1 year−1 (SD 0.9). The lack of juvenile fish at the location with the lowest estimated enhancement might be explained by the impact of overfishing on recruitment of key species or by an abundance of alternative habitat for juvenile fish. Synthesis and applications. The combination of underwater videos with automated data extraction provides a reliable, cost‐effective method for surveying fish on oyster reefs. By quantifying enhanced fish productivity on reefs, we provide estimates that will underpin calculations of ecological, social and financial benefits, supporting the business case for scaling‐up restoration efforts.

Multi-omics analysis provides insights into the enhancement of β-carotene and torularhodin production in oleaginous red yeast Sporobolomyces pararoseus under H2O2-induced oxidative stress

Carotenoids are one of the most widespread groups of naturally occurring pigments with extensive applications in the food, nutraceutical, pharmaceutical, and cosmetic industries. Sporobolomyces pararoseus is a well-studied oleaginous red yeast that has attracted rising interest as an alternative source of high-value-added carotenoids, consisting of β-carotene, torulene, and torularhodin. Here, the effect of different concentrations of H2O2 treatments on carotenoid contents in S. pararoseus CJR was investigated. The results showed that, after 120 h of incubation, the total amount of carotenoids was significantly increased in 5 mM (963.37 μg/gdw), 10 mM (1525.03 μg/gdw), 20 mM (1823.8 μg/gdw), 40 mM (2163.78 μg/gdw), and 60 mM (1116.94 μg/gdw) H2O2 treatments than control (935.1 μg/gdw), respectively. Meanwhile, the increase in β-carotene and torularhodin production was the main contributor to the enhancement of total carotenoids under H2O2 treatments. Multi-omics profiling revealed that the up-regulation of carotenogenic metabolic flux and the down-regulation of TCA cycle metabolic flux might be the main reasons for this increase in total carotenoids. Our findings not only offer an accessible and effective way to boost carotenoid synthesis in S. pararoseus but also establish the molecular basis to further enhance their production through genetic or metabolic engineering.

Catalytic action of hydronium-ion in rice straw pretreatment and enhancement of enzymatic hydrolysis and ethanol production

The present investigation will focus on the catalytic effect of hydronium ion during liquid-water/ dilute sulfuric acid/ferric chloride pretreatment (LWP/ SAP/ FCP) on the hydrolysate and pretreated rice straw. The overall pretreatment process has been represented as a sequential catalytic reactions. The temperature range of pretreatment is varied in the range of 140–180 °C and the concentration of dilute sulfuric acid and ferric chloride is 0.1 M. The first order rate constants of xylan and glucan degradation have been determined for LWP/ SAP/ FCP. The maximum xylan and glucan conversion of 96.8% w/wand 31.4%w/w respectively are achieved for FCP at 180 °C. Xylose, glucose, furfural, 5-hydroxymethyl furfural, acetic acid and formic acid appear as the main products for all pretreatments. Only in case of FCP levulinic acid also appears as a hydrolysis product. The thermal characteristics, functional groups, crystallinity, surface morphology of untreated and pretreated rice straw have been evaluated. Among all pretreatment processes under study, the highest values of glucose yield of 78.96% (w/w) using enzymatic hydrolysis and 83.79% of theoretical yield of ethanol using Saccharomyces cerevisiae have been achieved for ferric chloride pretreatment.

Development of an action classification method for construction sites combining pose assessment and object proximity evaluation

AbstractAddressing the inherent hazards of on-site construction work and stagnant labor productivity is crucial in the construction industry. To tackle these challenges, automated monitoring of construction sites and analysis of workers' actions play a pivotal role. In this study, we developed a method for classifying actions at a construction site from video, using deep learning. Specifically, we used two image processing techniques, pose assessment and object detection, and found that the accuracy of action classification was improved by extracting information on the proximity of workers to equipment installed at the construction site, and also by considering the pose information. For classification, LSTM (Long Short-Term Memory), CNN (Convolutional Neural Network), and XGBoost models were used, and the presence of proximity information improved average recall by 7.0% to 8.5% for all models used. The final model was developed as an ensemble of these methods, offering accuracy and average recall that are higher than with conventional methods. The methodology developed in this research enables quantification and visualization of work content at construction sites, contributing to the overall enhancement of safety and productivity within the construction industry.

Enhancement of cellulolytic enzyme production from intrageneric protoplast fusion of Aspergillus species and evaluating the hydrolysate scavenging activity

BackgroundLignocellulosic biomass provides a great starting point for the production of energy, chemicals, and fuels. The major component of lignocellulosic biomass is cellulose, the employment of highly effective enzymatic cocktails, which can be produced by a variety of microorganisms including species of the genus Aspergillus, is necessary for its utilization in a more productive manner. In this regard, molecular biology techniques should be utilized to promote the economics of enzyme production, whereas strategies like protoplast fusion could be employed to improve the efficacy of the hydrolytic process.ResultsThe current study focuses on cellulase production in Aspergillus species using intrageneric protoplast fusion, statistical optimization of growth parameters, and determination of antioxidant activity of fermentation hydrolysate. Protoplast fusion was conducted between A. flavus X A. terreus (PFFT), A. nidulans X A. tamarii (PFNT) and A. oryzae X A. tubingensis (PFOT), and the resultant fusant PFNT revealed higher activity level compared with the other fusants. Thus, this study aimed to optimize lignocellulosic wastes-based medium for cellulase production by Aspergillus spp. fusant (PFNT) and studying the antioxidant effect of fermentation hydrolysate. The experimental strategy Plackett-Burman (PBD) was used to assess how culture conditions affected cellulase output, the best level of the three major variables namely, SCB, pH, and incubation temperature were then determined using Box-Behnken design (BBD). Consequently, by utilizing an optimized medium instead of a basal medium, cellulase activity increased from 3.11 U/ml to 7.689 U/ml CMCase. The following medium composition was thought to be ideal based on this optimization: sugarcane bagasse (SCB), 6.82 gm; wheat bran (WB), 4; Moisture, 80%; pH, 4; inoculum size, (3 × 106 spores/ml); and incubation Temp. 31.8 °C for 4 days and the fermentation hydrolysate has 28.13% scavenging activities.ConclusionThe results obtained in this study demonstrated the significant activity of the selected fusant and the higher sugar yield from cellulose hydrolysis over its parental strains, suggesting the possibility of enhancing cellulase activity by protoplast fusion using an experimental strategy and the fermentation hydrolysate showed antioxidant activity.

Design and application of germanium based complementary TFET devices with step tunneling paths

Expanding tunneling has consistently been one of the approaches to enhance the on-state current (Ion) and performance of Tunnel Field-Effect Transistor (TFET). This paper proposes a novel structure for TFET called Step Tunneling Path TFET (STP TFET). The stepped tunneling path is achieved by preparing majority carrier channel and introducing pocket doping layers and lightly doped channel extension regions in the channel. Taking Germanium TFET as an example, the complementary structures, electrical parameters, DC and analog characteristics of STP TFET are investigated. Simulation results demonstrate that, compared to normal TFET, STP TFET exhibits significant improvements in Ion (n-TFET∼18/p-TFET∼45 times), cut-off frequency (n-TFET∼6/p-TFET∼16 times), Gain Bandwidth Product enhancement (n-TFET∼22/p-TFET∼16 times), and Transconductance Frequency Product enhancement (n-TFET∼3/p-TFET∼15 times). Furthermore, in the C-TFET inverter, the transient rise and fall times have decreased by 149 and 199 ns, respectively, while the voltage gain has increased by 6.7 times. The proposed device shows promising potential for applications in high-speed and low-power circuit designs.

Enhancement of isoflavonoid production and release in Pueraria candollei cell suspension culture using elicitors for improving pharmacological activities

Enhancement of isoflavonoid production and release in Pueraria candollei cell suspension culture using elicitors for improving pharmacological activities

Multi-mode enhancement and Co-fermentation mechanism of 2-phenylethanol production by Kluyveromyces marxianus

As a valuable aromatic alcohol, 2-phenylethanol has been widely used in the fields of food, medicine and chemistry, but its production has become a key factor limiting microbial industrialisation. Therefore, atmospheric and room temperature plasma (ARTP) mutagenesis was applied to improve host cell tolerance of 2-phenylethanol, and 2-phenylethanol production was increased from 2.23 g/L to 2.51 g/L in Kluyveromyces marxianus. Fermentation conditions of K. marxianus and Pediococcus lactis co-culture were optimised and production of 2-phenylethanol was further increased by 42.63%, reaching 3.58 g/L. Metabonomics analysis revealed that the cell wall of P. lactis could effectively activate Ehrlich pathway-related metabolism and upregulate arginine synthesis pathways to enhance the cellular robustness of K. marxianus, thereby improving the efficiency of 2-phenylethanol synthesis, and providing a novel strategy for cost-effective 2-phenylethanol production.

Financial Proximity and Agricultural Productivity: New Evidence from Sub-Saharan African Countries

ABSTRACT: Agriculture plays a vital role in driving economic output and employment in Sub-Saharan African (SSA) countries. Despite some progress, agricultural productivity in SSA still lags behind other regions. Limited access to finance remains a significant impediment to improving agricultural productivity in Sub-Saharan Africa. This paper investigates the effect of financial proximity on agricultural productivity in Sub-Saharan African countries. The study primarily employs the system GMM estimator, chosen to address the endogeneity issue typical in macro panel data. This method is also well-suited to our study because it accommodates a high number of cross-sections relative to the number of periods within each cross-section. Additionally, the IV-2SLS method is employed to check the robustness of the findings. The study uses an unbalanced panel for the 36 African countries with data for the period 2004-2019. Our findings show that increasing the financial proximity favors agricultural productivity in SSA countries. Specifically, the number of commercial bank branches (CBB) and the number of automated teller machines (ATM) per 100 000 adults, as indicators of financial proximity, have positive and significant effects on agricultural value added per worker in SSA. Additionally, our findings show that rainfall, arable land, and institutional quality are robust determinants of agricultural productivity. The positive effects of the number of CBB and the number of ATM are even more pronounced on agricultural productivity when coupled with strong institutional quality. Our findings suggest that improving financial services' accessibility in rural areas, coupled with enhanced institutional quality, regular rainfall, ample arable land, and increased access to water and land, are pivotal steps for achieving sustainable enhancements in labor productivity. This, in turn, leads to increased returns through value-added growth and expanded employment in the agricultural sector.

Production of high purity MoO3 from spent catalyst of formaldehyde synthesis process via a novel two-step leaching-cementation method

This study presents a two-step methodology for producing high-purity MoO3 from spent FORMOX process catalysts. In the first step, a leaching process with a Na2CO3 solution is used to get molybdenum out of formaldehyde synthesis catalyst. The second step involves molybdenum-ion cementation in the presence of metallic zinc powder and plates. The leaching process is thoroughly explored using the design of experiments (DOE) to analyze critical parameters such as temperature, leaching time, Na2CO3/Mo stoichiometric ratio, and catalyst average particle size. A robust quadratic model with an R2 value exceeding 97 % is developed, serving as a predictive tool for molybdenum extraction. Through rigorous numerical optimization, the optimal conditions for 100 % extraction were found to be 74.5 °C, 92.3 min, a stoichiometric ratio of 2.52, and a particle size of 183 μm. However, the use of zinc powder in the cementation stage introduces impurities due to increased solution pH and reduced zinc dissolution. The strategic adoption of zinc plates mitigates these challenges, resulting in a notable enhancement of the final product's purity. Over 91 % of MoO4-2 ions with a purity surpassing 99.8 % are successfully obtained as hexagonal MoO3 powder at 85 °C with an initial solution pH of 1.0 after 15 min of the cementation process.

Multidirectional pathway engineering of Mycobacterium neoaurum LY-2 for the enhancement of androstenedione production from phytosterols

Androstenedione (ADD), an important precursor for steroid hormone drug synthesis, can be obtained through the transformation of phytosterols by members of the Mycobacteria genus. In this study, multidirectional pathway engineering of Mycobacterium neoaurum LY-2 was applied to improve ADD production from phytosterols. Initially, the nonessential gene KasB encoding a cell wall β-ketoacyl acyl carrier protein synthase in Mycobacterium neoaurum LY-2 was knocked out, and the production of ADD was increased by 21.0%. Then, the key enzymes involved in ADD synthetic metabolism were systematically explored. These assays revealed that propionyl coenzyme A carboxylase (PCC) and Hsd4A played important roles in the synthesis of ADD. In addition, the heterologous expression of Vitreoscilla hemoglobin (VHb), a protein with oxygen-binding capacity, was successfully realized in Mycobacterium neoaurum LY-2, and the ADD concentration reached 4.42 g/L. Finally, the recombinant strain LY-2-ΔKasB-hsd4A-pcc-vgb with high ADD production was constructed by combining the above strategies. Through optimization of conversion conditions, the recombinant strain LY-2-ΔKasB-hsd4A-pcc-vgb produced an ADD concentration of 11.12 g/L when adding 20 g/L phytosterols.

Gastronomic Identity and the Role of the Confraternities in the Valorisation of Local Products. The Confraternity of Bucho Raiano in the Promotion of Culture and Inland Tourism

Abstract Considering gastronomy as a source of expression of local culture, its use in tourism can contribute to enhancing and adding value to the destination, as well as encourage the pride of the local community, stimulating its production and consumption, and its dissemination outside the region. Bucho Raiano is a gastronomic product of identity and representativeness for the inland border region of Portugal (Riba Côa), for which its confraternity seeks the dissemination, the promotion of its consumption, and enhancement as a cultural resource. In this context, we seek to frame the Bucho Raiano gastronomic product, its identity, and the role of the confreres in its promotion and dissemination. Thus, this research aims to contextualize the Confraria do Bucho Raiano as a case study, evaluate the confreres’ perception of the confraternity’s mission, its strategies and contributions to the promotion and enhancement of this gastronomic product. The aim is to find out whether Bucho can be an important tourist product for this region and, consequently, strengthen the link between traditional local gastronomy and the tourist destination, according to the confreres’ perception.

Application of group method of data handling and gene expression programming to modeling molecular diffusivity of CO2 in heavy crudes

Successful enhancement of heavy oil and bitumen production using CO2-based enhanced oil recovery (EOR) techniques requires extensive knowledge about the diffusivity of CO2 in heavy crudes. In this work, two advanced correlative approaches, namely group method of data handling (GMDH) and gene expression programming (GEP), were utilized to establish simple-to-use mathematical correlations by applying a comprehensive dataset including 260 laboratory data of CO2 diffusion coefficient (DC) in heavy crudes and taking into account all the parameters affecting the accuracy of the models. Moreover, the response surface and contour plots were analyzed to obtain the desired response values and operating conditions. The GMDH correlation represented more reliable results with better statistical criteria including average absolute percentage error (AAPRE) values of 7.47%, 7.83%, and 7.54% for training, testing, and the total sets, respectively. Also, the results showed that the increase in pressure and/or temperature caused an increment in the amount of diffusivity of CO2 in heavy crudes; and the maximum amount of CO2 DC was obtained at the upper limit of these operational parameters. At a given temperature and pressure, it appears that the highest CO2 DC in heavy crudes was obtained when the CO2 mass fraction was less than 0.02. Furthermore, the Pearson and Spearman correlation coefficients were used to investigate linear and non-linear relationships between input variables and the responses of GMDH and GEP correlations. The mass fraction of CO2, temperature, pressure, and temperature_PVT had a direct relationship, and on the other hand, the viscosity and density of crudes had a reverse relationship with CO2 DC. Finally, the reliability of the data bank of CO2 DC in heavy crudes along with the high validity of GMDH and GEP correlations was verified by the leverage technique. Notably, no out-of-leverage data were identified, with only seven and five data points considered as suspected for GMDH and GEP models, respectively.

The role of foreign direct investment in east and Southeast Asia: Evidence before and after 2009 global financial crisis

This research investigates the influence of Foreign Direct Investment (FDI), domestic physical stock, and the human capital index on labor productivity across 17 East and Southeast Asian economies. In the period from 1980 to 2009 (pre-global financial crisis), the study reveals that, initially, FDI stock independently contributes little to productivity. It underscores the necessity of specific human capital thresholds for FDI to enhance productivity by facilitating technology diffusion from source to host economies. While most economies in our sample surpass these thresholds, Cambodia, Laos, and Myanmar do not, indicating unexploited potential for productivity enhancement via FDI. In the post-2009 era, following the financial crisis, FDI emerges as the primary driver of labor productivity in these economies, rendering the previously mentioned human capital thresholds less critical across all 17 economies. The study also observes a significant, mutually intensifying crowding-out effect between FDI stock and domestic physical capital, which notably escalated around the 2009 financial crisis. Despite this, the influence of FDI stock on labor productivity substantially surpasses that of domestic physical capital, especially after 2009. These insights underscore the critical need for policymakers to strategically balance the influx of foreign investment with domestic capital investment to optimize economic growth in the aftermath of the 2009 crisis.

Land management without burning and corn productivity enhancement during long dry season in West Kalimantan, Indonesia

In long dry season (El Nino), thousand hectares of agricultural land in Indonesia to experience drought, and sometimes wildfires occur naturally. Land management without burning and environmentally friendly agricultural cultivation needs to be done in the long dry season. It is not recommended to use crop residue that is burned on the land, since the residue can be composted into organic matter which later is returned to the agricultural land as organic fertilizer. Currently, about 40% farmers use local corn varieties. Corn farming lands in Indonesia are generally deficient in nitrogen. Consequently, drought tolerant new superior corn varieties complemented with right dose fertilizer based on plant needs, especially N fertilizer, are needed to increase corn productivity in the dry season. This research aimed to ascertain adaptive hybrid corn varieties and right N fertilizer rate on the growth and productivity of corn planted on the land without burning. The experimental design was Randomized Complete Block Design consisting of 2 factors. The first factor was corn varieties, namely Bima 19, Nasa 29, and JH 21; whereas, the second factor was N fertilizer rate, namely 64, 86.5, 109, and 131.5 kg ha-1. The combination of the two factors consisted of 12 treatments, which were repeated 3 times. The results showed that there was an interaction between the new high yielding varieties and the N fertilizer rate on corn productivity. Greater yields were performed in Bima 19 with N rate of 109 and 131.5 kg ha-1 and Nasa 29 with N rate of 131.5 kg ha-1 i.e., 8.45, 7.94, and 8.04 t ha-1, respectively. Bima 19 and Nasa 29 are drought tolerant high yielding corn varieties.

Numerical simulation of multi-fracture uniform propagation in naturally fractured reservoirs based on the continuum–discontinuum method

Multi-cluster fracturing technology with horizontal wells is significant for the production enhancement of unconventional reservoirs. However, affected by the natural fracture distribution in the reservoir, stress shadowing between multi-fractures and perforation erosion has non-negligible influence on the multi-fracture uniform propagation, which results in uneven reservoir stimulation and lower production capacity. In this study, a multi-field coupled stress-seepage-fracture model for hydraulic fracturing of fractured reservoirs based on the continuum–discontinuum method was developed, adequately simulating the full scenario of stress disturbances, perforation erosion, and fracture interactions during the fracturing process. The effect of different geological and engineering parameters on the competing propagation of multi-fractures was investigated in detail, and the results show: Different geological and engineering parameters have significant influence on the competitive propagation of multi-fractures; among the geological parameters, the elastic modulus has the highest impact on the uniform fluid intake of multi-fractures, while the horizontal stress difference has the least impact on the uniform fluid intake of multi-fractures. Among the engineering parameters, the effect of natural fracture angle on the standard deviation of the fluid injection volume is gradually reduced with the increase in perforation number, flow rate, and fluid viscosity. For a low number of perforations and high fluid viscosity, both have great influence on promoting uniform fluid entry in multiple fractures. In addition, geological parameters have a significantly greater influence on the merging of multi-fractures than engineering parameters, and the probability of merging of multi-fractures increases significantly under low stress differentials and long natural fractures.