bluuebunny/crossref_metadata_2025 huggingface dataset:
Oil Recovery by Low-Rate Waterflooding in Water-Wet Sandstone Cores
Authors: Aslanidis Panagiotis , Strand Skule , Puntervold Tina , Yeboah Kofi Kankam , Souayeh Iyad
Published: June 2022

Smart Water or low salinity water injection are environmentally friendly methods for efficient hydrocarbon recovery. Wettability alteration towards more water-wet conditions and generation of positive capillary forces and spontaneous imbibition are responsible for the increased oil production. Spontaneous imbibition to expel oil from the low permeable matrix is a time-dependent process and both injection rate and oil viscosity are important factors affecting the contribution of capillary and viscous forces to the oil production.

It is hypothesized that when capillary forces and spontaneous imbibition are important for oil production, low flooding rate must be applied in laboratory corefloods to allow for wettability alteration. In this study the effect of flooding rate on oil displacement from low permeable sandstone cores has been examined. Viscous forces have been varied by injection at two different rates and performing spontaneous imbibition experiments, in addition to varying the oil viscosity. Low permeable, water-wet Bandera Brown outcrop sandstone cores were used as the porous medium, and synthetic oil and formation water were used to avoid any wettability alteration during fluid restoration and oil displacement.

The results showed only small differences in oil recovery by spontaneous imbibition and viscous flooding at high and low rate, proving that capillary forces and spontaneous imbibition were major contributors to the oil mobilization and production process. By varying the oil viscosity, the results indicated that capillary forces were especially important for oil displacement at higher oil viscosity, since the ultimate oil recovered by low-rate injection was higher than that from high-rate injection. As expected, capillary number calculations indicated that capillary forces were important for efficient oil displacement from the low permeable, water-wet cores used in this study. However, there was no direct link observed between generated pressure drops at high and low injection rate, including spontaneous imbibition, and the ultimate oil recovery. Thus, to simulate oil production in the middle of the reservoir it was concluded that low rate waterflooding is needed in laboratory tests to allow spontaneous imbibition into the matrix to displace oil by positive capillary forces.

The combination of using oils that differ in viscosity in different injection rates could add some additional information in the literature on how to increase the efficiency of waterflooding by a low injection rate.
Viscosity from Geochemical Techniques: A Case Study for a Heavy Oil Field on the UKCS
Authors: Cutler Ian , Cely Alexandra , Moore Julian , Yang Tao , Birch Nicholas , Ablard Peter
Published: June 2022

Heavy oil fields are characterised by complex chemistries and exhibit a wide range of physical properties (especially oil viscosity). This paper describes the development of two innovative and cost-effective data acquisition methods: the optimised use of mud gas data and the geochemical characterisation of cuttings extracts, both as an alternative data source for oil viscosity determination. Applications of these methods can lead to the cost reduction of data acquisition programs and potentially improvements in oil recovery.

The mud gas provides real-time surface logging data. Due to the nature of heavy oil in the case study wells, the mud gas compositions contain mainly C1-C3. By comparing with the reservoir oil samples from the exploration and appraisal wells, we investigated the possibility of using mud gas while drilling to identify if the reservoir oil belongs to the high viscosity or medium viscosity group. For cutting analysis, we thoroughly investigated solvent extracts from cuttings from the exploration and appraisal wells and correlated them with the oil viscosity from the corresponding PVT samples. When such a correlation is established, we can then apply the correlation to predict oil viscosity from the cuttings of new production wells.

We achieved excellent results for both real-time oil viscosity identification from mud gas data and post well oil viscosity prediction from the extraction of cuttings. The C1/(C2+C3) is the key parameter for oil viscosity identification from the standard mud gas data in the field. For the past wells, the mud gas interpretation has high accuracy for determining if the reservoir oil belongs to the high viscosity or medium viscosity regions. We established a strong correlation between the biomarkers and the oil viscosity from the exploration and appraisal wells. When we applied the correlation to new production wells, the oil viscosity prediction was very close to the viscosity measurement from the wellhead PVT samples.

The geochemical techniques provide oil viscosity for critical decisions regarding well placement and reservoir management modelling. The new source of reservoir fluid data from mud gas and cuttings provides real-time fluid interpretation while drilling and close to PVT sample quality oil viscosity prediction after drilling. This new approach is cost-efficient and has a large potential to replace the downhole fluid sampling or expensive downhole logging tools for production wells.
Construction of Single-Porosity and Single-Permeability Models as Low-Fidelity Alternative to Represent Fractured Carbonate Reservoirs Subject to WAG-CO2 Injection Under Uncertainty
Authors: Menezes Davi Eber Sanches de , Santos Susana Margarida da Graça , Santos Antonio Alberto de Souza dos , Hohendorff Filho João Carlos von , Schiozer Denis José
Published: June 2022

Fractured carbonate reservoirs are typically modeled in a system of dual-porosity and dual-permeability (DP/DP), where fractures, vugs, karsts and rock matrix are represented in different domains. The DP/DP modeling allows for a more accurate reservoir description but implies a higher computational cost than the single-porosity and single-permeability (SP/SP) approach. The time may be a limitation for cases that require many simulations, such as production optimization under uncertainty. This computational cost is more challenging when we couple DPDP models with compositional fluid models, such as in the case of fractured light-oil reservoirs where the production strategy accounts for water-alternating-gas (WAG) injection. In this context, low fidelity models (LFM) can be an interesting alternative for initial studies. This work shows the potential of compositional single-porosity and single-permeability models based on pseudo-properties (SP/SP-P) as LFM applied to a fractured benchmark carbonate reservoir, subject to WAG-CO2 injection and gas recycle. Two workflows are proposed to assist the construction of SP-P models for studies based on (i) nominal approach and (ii) probabilistic approach of reservoir properties. Both workflows begin with a parametrization step, in which the pseudo-properties are optimized for a base case in order to minimize the mismatch between forecasts of the SP/SP-P and DP/DP models. The new parametrization methods proposed in this work showed to be viable for the construction of the SP/SP-P models. For studies under uncertainties, the workflow proposes obtaining pseudo-properties by robust optimizations based on representative models from a DP/DP ensemble, which proved to be an effective method. The case study is the benchmark UNISIM-II-D-CO with an ensemble of 197 DP/DP models and two different production strategies. The risk curves for production, injection and economic indicators obtained from DP/DP and SP/SP-P ensembles showed good match and the computational time spent on simulations of the SP/SP-P ensemble was 81% faster than DP/DP models, on average. Finally, the responses obtained from both ensembles were validated in a reference model (UNISIM-II-R) that represents the true response and is not part of the ensemble. The results indicate the SP/SP-P modeling as a good LFM for preliminary assessments of highly time-consuming studies. Besides, the workflows proposed in this work can be very useful for assisting the construction of SP/SP-P models for different case studies. However, we recommend the use of the high-fidelity models to support the final decision.
Simulation Evaluation of CO2-ECBM Potential in Karaganda Coal Basin in Kazakhstan
Authors: Serikov Galymzhan , Wang Lei , Asif Mohammad , Hazlett Randy
Published: June 2022

Karaganda Coal Basin is the largest coal basin in Kazakhstan with around one trillion cubic meters of coalbed methane, which has not been tapped to date. Also, simulation research on the production of coalbed methane from the Karaganda Coal Basin has not been conducted. Seeing that primary production of coalbed methane (CBM) is generally slow and recovery is not high, we proposed to evaluate the potential of implementing CO2-ECBM processes in Karaganda Coal Basin in Kazakhstan. It is known that CO2 adsorption on coal is much higher than methane so it is important to study the displacement mechanisms by CO2 injection. Using the geological parameters collected for Karaganda Coal Basin, main factors affecting methane production including different rates of CO2 injection and different starting times of CO2 injection were simulated and compared. CO2 injection into CBM reservoir is predicted to be effective due to competitive adsorption of these gases. This study provides a workflow model for evaluating and predicting efficient CBM production from the Karaganda Coal Basin. Results from simulation studies showed that injection of 110,000 m3/day of CO2 is as practical as injection of 150,000 m3/day, with small difference in recovery factor. The methane production enhances from 68.32% to 73.67-74.62% at injection pressure 15,000 kPa. The CO2 injection after 30% of primary recovery is the most efficient option. Early injection results in early breakthrough and high CO2 content in the producer well, while late injection leads to relatively low incremental recovery factor.
What Have We Learn from the Most Prolific Pad of Shale Gas in the Sichuan Basin?
Authors: Wang Meng , Che Mingguang , Jiang Yun , He Chunming , Weng Dingwei , Zhu Guangyou
Published: June 2022

There are more than 1300 horizontal wells in the Sichuan Basin shale reservoirsthat produce more than 20 billion cubic meters of gas in 2021. A test production of best-performing shale gas pad,so far in China, consisting of 8 horizontal wells, is over 4.7 × 106 m³/d (167.7 MMcf/d). The average EUR per well is estimated to exceed 2.0 × 108 m³(7.0 bcf).The underlying geological controlling factors including TOC content, porosity, gas saturation and brittle mineral content for these prolific wells were analyzed. The length of the well laterals drilling into the sweetest pay zone was characterized by well logging. The strategies of optimizing drilling and completion strategies used in these wells are discussed. In addition, the solutions to deal with the frequent occurrence of casing deformation are also proposed and adopted. Rate transient analysis was performed on these wells to assess the stimulation efficiency, which was further compared with those wells treated by conventional stimulationstrategies. It was found that the thickness and length of the completion in the highest quality pay zone are the two main geological controlling factors for the prolific wells. Different from the conventional stimulation strategies, the eight wells in one pad were all treated using higher intensity stimulation strategies. The average spacing between treated stages ranges from 85 m to 91 m, with tighter cluster spacing. Fracturing was temporarily plugged to passively treat sever deformation in two laterals consisting of 29 stages (total length of 2068m). Compared with the neighboring offset wells, the average bulk linear flow parameter of these eight well is 72% higher. Integration of geological designs (like sweet spot optimization) and engineering designs (such as tighter cluster spacing within longer stages, temporarily plugging fracturingand using more proppants), created a high-productivity template for the next stage of efficient developments of shale gas. The findings obtained in this study are also beneficial to unlock unconventional resources including shale oil and tight gas in China.
Designing CO2-EOR in Indonesia by Matching Business Strategy: Study Case East Java Field, Indonesia
Authors: Panggabean Yan Bastian , Pramadewi Tania Busran , Kusuma Erwin Andri , Maryanto Adam
Published: June 2022

JTB and SKW Field are proven fields which are hydrocarbon producing fields in Indonesia. JTB Field which is part of the Cepu Block is a proven field as well as the SKW Field which belongs to Pertamina EP Block. These two fields are 40 km apart and are currently a stranded field due to different operators. The JTB field is an early development field with CO2 characteristics > 35%, while the SKW field is a mature field with oil producers. The SKW field has been produced for more than 30 years so it is a mature field with a fairly high decline rate.

Feasibility Study conducted to these project to know incremental value, especially value of engineering and carbon emission incentives from this project. After the formation of integration in the existing fields, where these two fields are under 1 Region, so that the integration of these two fields becomes possible. This integration is necessary considering that currently the JTB Field will be onstream in 2022, while on the one hand the SKW Field has started studies related to CO2 EOR. The pilot project that will be implemented is expected to be a pilot and proof of CO2 EOR which is a very new technology in the oil and gas industry in Indonesia.

Carbon emissions for around that can be saved with this method become integrated value engineering that provides value creation. For implementation on pilot phase, capital expenditure about USD 75 millions with additional carbon value around USD 30 millions. This paper will use a Value engineering approach combined with environmental analysis to see the value and incremental value for these two fields. Feasibility Study of this integrated project will be used for searching another financing and get evaluated by project sanctions

Deliverable for this feasibility study to calculate incremental return and amount of carbon emission value for this integrated project.
Estimation of the Half-Length of Non-Simultaneous-Closed Fracture Through Pressure Transient Analysis: Model and Case Study
Authors: Wang Zhipeng , Ning Zhengfu , Jia Zejiang , Cheng Qidi , Zhang Yuanxin , Guo Wenting , Zhu Qingyuan
Published: June 2022

During water-flooding development, severe water breakthrough has been observed in fractured wells. It is essential that determine the reason for water-breakthrough to improve the performance of production wells. However, the conventional pressure-transient analysis model hardly characterizes fracture-induced pressure response and fracture half-length, leading to erroneous results. This paper aimed at present an approach to estimate the half-length of non-simultaneous fracture induced in a relatively economical way. The non-simultaneous fracture closure flow (NFCF) model was proposed to characterize flow in induced fracture. To better characterize pressure response in induced fracture, we first modeled fluid flow in fracture with variable conductivity by two-part, variable-conductivity-linear flow and low-conductivity-linear flow. At the same time, fracture closure was considered to occur twice according to the pressure response of water injection wells, and its condiction followed experimental results. As a result, a semi-analytical solution was developed. We compared it with the finite-conductivity model to certify the accuracy. A new flow regime (the non-simultaneous fracture close linear flow) was discovered and behaved as two peaks on the pressure derivative curve. It will shorten the half-length of induced fracture if the new flow regime is ignored. Case studies showed that the NFCF model matched well with field data, which validated the practicability of the proposed approach. Our results might help accurately understand the reason for the water breakthrough - enormous the half-length of induced fracture was ignored in the past. In addition, the results also have provided significant insight for the operators could make reasonable decisions, reasonable well spacing and water-flooding rate, to improve production and water injection wells performance.
Understanding the Controlling Factors for CO2 Sequestration in Depleted Shale Reservoirs Using Data Analytics and Machine Learning
Authors: Hassan Baabbad Hassan Khaled , Artun Emre , Kulga Burak
Published: June 2022

Carbon capture and sequestration (CCS) will generate an industry comparable to, if not greater than, the existing oil and gas sector. Carbon capture and sequestration is the capture of carbon-dioxide from refineries, industrial facilities, and major point sources such as power plants and storing it in subsurface formations. Subsurface formations like unconventional reservoirs can be a good example for storing carbon-dioxide. Despite its importance in the oil and gas industry, our understanding of carbon-dioxide sequestration in unconventional reservoirs still needs to be developed. The objective of this paper is to identify the most important parameters that affect carbon-dioxide sequestration in depleted shale reservoirs using data-analytics and machine-learning.

The dataset used was an extensive shale reservoir dataset which comprised a large set of numerical simulation scenarios. A quality check of the input data was performed for missing variables. Then, a data-analytics based investigation was followed to develop insights into the relationship between reservoir parameters and operational parameters, which were the main predictor variables, as well as between the predictor variables and the main response variable: cumulative CO2 injected. Machine-learning based predictive models such as multiple linear regression, regression tree, bagging, random forest, and boosting were built to predict the cumulative CO2 injected. Variable importance (screening) was carried out to determine the crucial parameters which drive CO2 sequestration performance in shale reservoirs.

The results revealed that there is a relationship between the reservoir and operational parameters, together with the predictor variables and response variable. Operational parameters displayed a monotonic relationship with the cumulative CO2 injected. Random forest provided the best predictive ability among the machine-learning techniques consistent with the theoretical background of random forest. Regression tree had the worst predictive ability mainly because of overfitting. Screening results show that stimulated reservoir volume fracture permeability was the most important variable for the performance of CO2 sequestration. The findings and results reported in this study will allow the exploration and production companies to determine what causes low-performance or high-performance CO2 sequestration process in shale reservoirs.
Impact of Field Development Strategies on CO2 Trapping Mechanisms: A Case Study of CO2-EGR in the DND Tight Gas Field
Authors: Jia Ying , Huang Lei , Yan Jin
Published: June 2022

This paper presents field-scale compositional reservoir flow modeling in the DND tight gas field, to demonstrate the relative partitioning of 3 during and after CO2 injection. The model was developed to study the effect of structural trapping, solubility trapping, residual trapping, and mineralization trapping on the partitioning of CO2 in gas (free or residual), and brine phases over time. Furthermore, we investigated the impact of various injection scenarios, such as Injection pressure, Injection rate and Injection time, on the different trapping mechanisms. First, we used a high-resolution geo-model, which was constructed from wireline logs, seismic surveys, core data, and stratigraphic interpretation. As the initial distribution of fluids plays a vital role in CO2 partitioning, a comprehensive pressure-production history matching was completed. The hysteresis model was used to calculate the amount of CO2 trapped as residual. The water-rock reaction models among CO2 and minerals were added to analyze the mineralization trapping mechanism. CO2 solubility into brine was verified based on experiments. The model results show a new understanding of relative CO2 partitioning in porous media. Although it was believed that structural trapping is the largest of the trapping mechanisms during CO2 injection and post-injection, our results show that in sandstone tight gas field like DND tight gas field, the solubility of CO2 in gas plays a very important role, even in the first stage of CO2 injection. Porosity changes caused by the reaction among CO2 and different minerals during CO2 storage were also analyzed. Comprehensive models were run to estimate the amount of trapped CO2 during and after the injection period. The present work provides valuable insights for optimizing gas production and CO2 storage in sandstone reservoirs like DND tight gas field.
Time-Dependent Moderating Effect of Exposure to Nature on Relations between Perceived Interior Crowding, Social Isolation, and Psychological Distress of Residents during Pandemic of COVID-19
Authors: Mousavinia Seyyedeh Fatemeh
Published: June 2022

Due to the results of the COVID-19 epidemic on mental health, some studies have highlighted the positive effects of nature exposure. Nevertheless, this beneficial role has not yet been explored over time of the pandemic. In mid-rise housing, in addition to the small home size, most people do not have access to private outdoor spaces and they use shared open and green areas. It is necessary to understand how household density and nature exposure affect people's mental health in this housing type. The current study examines the longitudinal changes in (a) social isolation, (b) psychological distress, (c) intensity of the effect of social isolation on psychological distress, and (d) moderating effect of nature exposure on the relation between perceived interior crowding, social isolation, and psychological distress. Focusing on six mid-rise housing developments in Mashhad, longitudinal data were collected from 718 middle-aged women (Mage = 49.63, SD = 12.39) in two waves during the Iranian national lockdowns (wave1 in May 2019 and wave2 in April 2020, before nationwide vaccination). A paired-sample t-test showed increased social isolation and psychological distress after one year of the pandemic. Also, using structural equation modeling and multi-group analysis (wave 1 vs. wave 2) revealed that social isolation has an increasing influence on psychological distress over time. Exposure to nature moderates the effect of perceived interior crowding on psychological distress. However, this moderating role is time-dependent and nature exposure during the time did not necessarily assist in reducing the negative impact of perceived interior crowding. Finally, at any given time, nature exposure mitigated the effect of social isolation on psychological distress.
The association of blood urea nitrogen to creatinine ratio and the prognosis of critically ill patients with cerebral infarction: a cohort study
Authors: Chen Ting , Li Aiping , Gong Qi , Zhou Lin , Zhao Yixuan , Zhou Zhiwen , Zhou Wensheng
Published: June 2022

Background
To evaluate the association between blood urea nitrogen (BUN) to creatinine (Cr) (BUN/Cr) ratio with the in-hospital mortality of critically ill patients with cerebral infarction in intensive care unit (ICU).
Methods
In this cohort study, the data of 3059 participants with cerebral infarction were collected from the Medical Information Mart for Intensive Care (MIMIC)-III and the MIMIC-IV database. After propensity score matching (PSM) on age and gender, 2085 people were involved in and divided into the alive group (n = 1390) and the dead group (n = 695). All subjects in the ICU were followed up until death or discharge. Multivariate logistic analyses were applied for identifying the confounders and the association between BUN/Cr and mortality of cerebral infraction.
Results
The median follow-up time was 10.5 days. Among 2778 participants, 695 were dead at the end of follow-up. Univariate analysis revealed that BUN/Cr [risk ratio (RR) = 1.01, 95% confidence interval (CI): 1.01–1.02] might be associated with the in-hospital mortality of cerebral infraction patients. After adjusting respiratory failure, malignant cancer, anticoagulation, liver disease, white blood cell (WBC), red cell distribution width (RDW) percent, glucose, bicarbonate and temperature, BUN/Cr was associated with an increased risk of in-hospital mortality of cerebral infraction patients (RR = 1.01, 95%CI: 1.01–1.02).
Conclusion
This study evaluated the association between BUN/Cr and the in-hospital mortality of cerebral infarction patients in ICU and found BUN/Cr was associated with an increased risk of in-hospital mortality of patients with cerebral infarction in ICU especially in males, and those with respiratory failure, malignant cancer and without liver disease, as well as those receiving anticoagulation. The findings of our study reminded the clinicians to pay attention on the level of BUN/Cr in cerebral infarction patients in ICU.
Multi-objective optimization of fused deposition modelling for mechanical properties of biopolymer parts using Grey-Taguchi Method
Authors: KUMAR KAPIL , Singh Hari
Published: June 2022

Development of customized functional products for engineering and biomedical applications is a prime objective of 3D printing techniques. As a biomedical application, fabrication of surgical instruments, namely, forceps and hemostat using fused deposition modelling (FDM) process is proposed in this article. The mechanical properties of FDM processed parts depend on various process parameters such as layer height, infill pattern, top/bottom pattern, number of top/bottom layers, infill density, flow, number of shells, printing temperature, build plate temperature, printing speed and fan speed. Tensile strength and modulus of elasticity are chosen as evaluation indexes to ascertain the mechanical properties of poly lactic acid (PLA) parts printed by FDM. Taguchi’s L27 orthogonal array (OA) is used to perform the experimentation. Analysis of variance (ANOVA) is used to ascertain the significance of the process parameters and their percent contributions on the evaluation indexes. Finally, an optimal set of the FDM process parameters is obtained by using grey relational analysis (GRA) in order to fabricate the best parts having comprehensive mechanical properties. The types of defects and strong bonding between rasters have been examined by Scanning electron microscopy (SEM).
Outbreak investigation of community associated methicillin-resistant Staphylococcus aureus in a primary and secondary school in Eastern Switzerland
Authors: Waldeck Frederike , Seiffert Salome , Manser Susanne , Zemp Danuta , Walt Angela , Berger Christoph , Albrich Werner C. , Schlegel Matthias , Roloff Tim , Egli Adrian , Nolte Oliver , Kahlert Christian R.
Published: June 2022

Background
In 2018 the number of newly detected methicillin-resistant Staphylococcus aureus (MRSA) cases in children attending primary (age 6–12 years) and secondary school (age 13–16 years) nearly doubled compared to previous years.
Methods
This observation initiated an epidemiological outbreak investigation including a cross-sectional study to determine source of the outbreak, colonization frequency and to identify risk factors for transmission using a questionnaire and to end the outbreak.
Results
During the investigation, 49 individuals were detected with 57 corresponding isolates. Based on the case definition combined with whole genome sequencing, a core cluster was identified that shared common genetic features and a similar antimicrobial susceptibility pattern (efflux-mediated macrolide resistance, tetracycline susceptibility along with presence of Panton-Valentine leukocidin).
Conclusions
Epidemiologic evaluation identified a distinct school as a common risk factor. However, the source of the clustered infections within that school could not be further specified. No further cases could be detected after decolonization of infected and colonized children.
Fate and health risk assessment of heavy metals in Brassica chinensis L. (pak-choi) and soil amended by sludge-based biochar
Authors: Zhang Shijie , Gu Weihua , Bai Jianfeng , Dong Bin , Zhao Jing , Zhuang Xuning
Published: June 2022

Biochar is widely used in agriculture to efficiently solve the problem of sludge. In this study, sludge-based biochar (referred to as BC1, BC2, and BC3) was prepared by mixing sludge with FeCl 3 , Na 2 SiO 3 , and Ca (H 2 PO 4 ) 2 , respectively. Then, it was mixed with fresh soil to plant Brassica chinensis L. The analysis of the effects of the three biochar types showed that all of them were beneficial to the growth of Brassica chinensis L. We added the biochar to the soil and found that the concentration of heavy metals did not exceed the recommended threshold. Additionally, the aboveground part of Brassica chinensis L. met the standard requirement for food safety (GB2762-2017). Notably, BC3 stood out with the best effect on the growth of Brassica chinensis L. and resulted in the improvement of the physical and chemical properties of soil such as ammonium nitrogen, available phosphorus, and available potassium (BC3 was followed by BC2 and BC1). BC3 could efficiently inhibit the migration of heavy metals, thereby reducing the overall heavy metal pollution level and ameliorating the soil nutrients. BC3 could increase the organic carbon by 258.92%, available phosphorus by 234.45%, and available potassium by 37.12% compared with the CK group. The THQ and TTHQ estimates of Brassica chinensis L. were lower than one, indicating that the health risk of heavy metal intake was not prominent. Additionally, the application of the proposed biochar could reduce the form of F1 (acid extracted state) and increase the form of F4 (residue state) in soil. Overall, we conclude that the application of the proposed biochar can promote the root absorption of heavy metals and inhibit the migration of heavy metals.
Time-Frequency Analysis based Deep Interference Classification for Frequency Hopping System
Authors: Xu Changzhi , Ren Jingya , Yu Wanxin , Jin Yi , Cao Zhenxin , Wu Xiaogang , Jiang Weiheng
Published: June 2022

It is known that, interference classification plays an important role in protecting the authorized communication system and avoiding its performance degradation in the hostile environment. In this paper, the interference classification problem for the frequency hopping communication system is discussed. Considering the possibility of presence multiple interferences in the frequency hopping system, in order to fully extract effective features of the interferences from the received signals, the linear and bilinear transform based composite time-frequency analysis method is adopted. Then the time-frequency spectrograms obtained from the time-frequency analysis are constructed as matching pairs and input to the deep neural network for classification. In particular, the Siamese neural network is used as the classifier, where the paired spectrograms are input into the two sub-networks of the deep networks, and these two sub-networks extract the features of the paired spectrograms for interference type classification. The simulation results confirm that the proposed algorithm can obtain higher classification accuracy than both traditional single time-frequency representation based approach and the AlexNet transfer learning or convolutional neural network based methods.
Performance Analysis of Generalized Frequency Division Multiplexing in Various Pulse-shaping Filter with raised cosine and root raised cosine filter
Authors: Gupta Megha , Gamad R.S
Published: June 2022

Generalized frequency division multiplexing (GFDM) is non orthogonal multicarrier modulation scheme which is suitable for the fifth generation (5G) of wireless network. Pulse shaping filter design in GFDM system have effects on symbol error rate performance due to inter symbol interference (ISI). In this paper Contribute to symbol error rate (SER) performance in GFDM system with additive white Gaussian noise channel (AWGN), zero forcing channel (ZF) rayleigh fading has been analyzed for pulse shaping filter namely raised cosine (RC) and root raised cosine filter (RRC) and also Simulation is done and results are reported in terms of symbol error rate (SER), signal to noise ratio (SNR), different value of roll off factor and different modulation technique. Comparison of simulation results of this method with existing methods is done and improvements in result are obtained as compared to existing.
Hydropower development in the Himalaya: Identifying critical river stretches
Authors: Bartwal Tanuja , Nautiyal Prakash
Published: June 2022

Two hydroelectric projects are operational in the upper and lower stretches of the river Alaknanda near Lambagarh and Srinagar that are respectively ~ 140 km apart. The health of the river ecosystem in the flowing stretches between and below these projects was bio-assessed, based on widely used diatom indices and van Dam ecologic values computed by OMNIDIA software. Samples were collected from Birahi, the semi-natural stretch - 53 km downstream of power-house, Narkota, the impacted stretch 27 km upstream Srinagar dam and Bagwan, the highly regulated stretch 22 km downstream Srinagar. IPS and IBD revealed mild pollution in upper and lower stretch compared to relatively elevate at Narkota. However TDI indicates moderate organic pollution at Birahi and Narkota, whereas the IDSE indicates low degradation at all stations. The prevalence of tolerant N-autotroph, β-mesosprobe, mesotrophic and aquatic to aerophilic categories of van Dam environmental variables indicate that a certain level of impact already persists due to organic-cum-nutrient load and perturbed flow-regime. The prevalence of eutrophic and moderate O2 categories shows that the ecosystem is in critical state at Narkota, causing a disrupted continuum.
Understanding the dynamic of POMS infection and the role of microbiota composition in the survival of Pacific oysters, Crassostrea gigas.
Authors: Delisle Lizenn , Laroche Olivier , Hilton Zoë , Burguin Jean-François , Rolton Anne , Berry Jolene , Pochon Xavier , Boudry Pierre , Vignier Julien
Published: June 2022

Background:In recent years, the aquaculture industry of Crassostrea gigas has been severely impacted by geographically widespread outbreaks of a polymicrobial disease, the Pacific Oyster Mortality Syndrome (POMS). The aetiology of these recurring summer mortality events and the disease progression have notably been recently described in France, revealing a combined development of viral (namely the Ostreid Herpesvirus, OsHV-1 µVar) and bacterial infections. In New Zealand (NZ), mass mortality episodes associated with OsHV-1 have been recorded in juvenile C. gigas since 2010 and selective breeding to improve resistance to OsHV-1 has been effectively used to mitigate the impact of the disease. However, POMS infection process and the role of the host-microbiota during infection have still not been well established in NZ. Results:Using a laboratory-based experimental infection approach, we challenged ten biparental oyster families with previously established contrasted genetically based ability to survive POMS in the field. Molecular analyses (viral load quantification, viral gene expression and 16S rRNA gene sequencing) were combined with histopathological observations to describe the temporal kinetics of infection to POMS and to characterize the role of microbiota during infection. Our main findings showed (1) a delay in viral infection resulting in a late onset of mortality in oysters compared to previous observations from France, and (2) a lack of evidence of major fatal bacteraemia in infected oysters. Bacterial profiling associated the microbiota composition with mortality rate, viral load, and viral replication, allowing the identification of potentially deleterious and beneficial bacterial taxa that can influence the outcome of the disease. Mycoplasma ASV-1 was identified as a significant predictor of mortality in oysters. Conclusion:Collectively, these results could improve current disease management and aquaculture practices and help understanding the mechanisms behind genetic resistance to POMS. Ultimately, microbiome composition could be used to predict oyster mortality following exposure to OsHV-1 and be used as a complementary screening tool in selective breeding and/or a diagnostic tool to determine shellfish health.
miR-4653-3p overexpression is associated with a poor prognosis of pancreatic ductal adenocarcinoma via HIPK2 downregulation
Authors: Hirabayashi Kenichi , Miyazawa Masaki , Takanashi Yumi , Morimachi Masashi , Kawanishi Aya , Saika Tsubasa , Nakagohri Toshio , Nakamura Naoya
Published: June 2022

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignant tumor. Several upregulated or downregulated microRNAs (miRNAs) are associated with invasiveness, tumorigenesis, and prognosis of PDAC. This study evaluated miR-4653-3p expression and pancreatic intraepithelial neoplasia (PanIN) using in situ hybridization and the association between miR-4653-3p expression and clinicopathological factors in patients with PDAC. The miR-4653-3p target was also identified. Ninety PDAC cases, including 30 normal pancreatic ducts, 30 low-grade PanINs, and 30 high-grade PanINs were evaluated. miR-4653-3p expression was absent in normal pancreatic ducts and increased in the following order: normal pancreatic duct, low-grade PanIN, high-grade PanIN, and PDAC. High miR-4653-3p expression significantly correlated with advanced pathological T stage, lymph node metastasis, advanced UICC stage, perineural invasion, venous involvement, and shorter overall survival. Homeodomain Interacting Protein Kinase 2 (HIPK2) was identified as a miR-4653-3p target based on mRNA microarray analysis and database screening. In vitro analysis using pancreatic cancer cells showed that miR-4653-3p significantly downregulated HIPK2 expression. Immunohistochemical analysis showed that HIPK2 expression inversely correlated with miR-4653-3p expression in PDAC surgical specimens. In contrast to miR-4653-3p, HIPK2 expression decreased gradually from the normal pancreatic duct to low-grade PanIN, high-grade PanIN, and PDAC. Additionally, low HIPK2 expression was associated with shorter overall survival in patients with PDAC. These results indicate that miR-4653-3p is associated with tumorigenesis and a worse prognosis, partly by reducing HIPK2 expression.
The Role of Plasmids in Antibiotic Resistance in Pasteurella multocida Isolated from Various Sources
Authors: Tabatabaei Mohammad , Joghataei Syed Mehdi
Published: June 2022

Antimicrobial resistance transmitting agents present in animal products and antibiotic use contributed to its occurrence and aggravation. The emergence of resistance toward several antibiotics groups among pathogenic bacteria is a growing global threat, and Pasteurella multocida is no exception in this case. The role of plasmids in creating different patterns of AMR on anyone is not hidden. One of the easiest ways to reduce antibiotic resistance is to stop the plasmid from replicating, dividing, and transferring by removing the plasmid. In this study, we investigated the role of P. multocida plasmids in the occurrence of antibiotic resistance. From different geographical regions of Iran, 131 definite isolates of P. multocida have been isolated from apparently healthy and sick animals. After plasmid DNA extraction, five isolates with evident plasmid were selected. Restriction mapping is used to determine the size of plasmids, so the restriction enzymes BglII, SspI, AluI were used to cleave the plasmids.Plasmid curing was performed, anddisk diffusion method was utilized to compare the antibiotic resistance pattern before and after plasmid curing. We found that the samples that contain plasmids and exhibited extensive antibiotic resistance did indeed lose their ability to resist antibiotics after their deletions and became sensitive to them. Indeed, this observation confirms the role and importance of plasmids in antimicrobial resistance in P. multocida. The study indicates that the ability of these isolates to retain plasmids has a significant effect on their ability to develop resistance to various antibiotics.
Functional linear mixed effects models for cytotoxicity assessment and clustering
Authors: Ma Tiantian , Richard Dan , Yang Yongqing , Kashlak Adam , Anton Cristina
Published: June 2022

A multitude of natural and synthetic chemicals are present in our environment. Through the study of a compound’s cytotoxicity, researchers can carefully set regulations regarding how much of a certain chemical in the ambient environment is tolerable. In the past, research has focused on point measurements such as the LD50. Instead, we consider entire time-dependent cellular response curves through the application of functional mixed effects models. We identify differences in such curves corresponding to the chemical’s mode of action—i.e. how the compound attacks human cells. Through such analysis , we identify curve features to be used for cluster analysis via application of both k-means and self organizing maps. The data is analyzed by making use of functional principal components as a data driven basis and separately by considering B-splines for identifying local-time features. Our analysis can be used to drastically speed up future cytotoxicity research.
Synthesis, Ligating Properties, Thermal Behavior, Computational and Biological Studies of Some Azo-transition Metal Complexes
Authors: Masoud Mamdouh S. , Hemdan Sokaina S. , Elsamra Rehab M. I.
Published: June 2022

Synthesis of new Fe(III), Co(II), Ni(II), and Cu(II) complexes of two azo ligands; 1-(phenyldiazenyl) naphthalene-2-ol (sudan orange R, HL1), and sodium 2-hydroxy-5-[(E)-(4-nitrophenyl) diazenyl]benzoate (alizarin yellow GG, HL2) have been reported. Stoichiometries of 1:2 and 1:3 (M:L) of the synthesized complexes were approved by total-reflection X-ray fluorescence technique (TXRF) and by elemental analyses. Complexes geometry of octahedral and square planar types were characterized by various spectroscopic, thermal, and magnetic moment measurements. Notably, bidentate coordination was the common binding mode of the ligands under investigation. The ESR spectroscopy showed that Cu(II) complexes are of different isotropic and rhombic symmetries accompanied by the existence of Cu-Cu ions interaction. TGA, DTA and DSC techniques supported the multi-stage thermal decomposition mechanisms, where the thermal breakdown is ended by the formation of metal oxide in most cases. Moreover, optimization of the structure and chemical reactivity modeling using the density functional theory (DFT) method with the B3LYP/6–31 basis set, showed that metal complexes are more biologically active than their precursor ligands. The calculated lipophilicity character for metal complexes is in the range 33.8–37.5 eV. Furthermore, nucleophilic and electrophilic regions on the surface of the ligands have been mapped aiming to prove the preferable sites of interaction with the metal ions. Docking results revealed high scoring energy for [Fe(HL2)3].H2O complex and moderate inhibition strength of [Cu(L1)2].H2O complex versus 1bqb, 3t88 and 4esw proteins. Ultimately, the extent of biological effectiveness was endorsed experimentally against four microbial strains. The results are guidelines for toxicological investigations.
Effect of ultrasonic vibration on porosity suppression and columnar-to-equiaxed transition in laser-MIG hybrid welding of aluminum alloy
Authors: Tan Caiwang , Xu Bingxiao , Liu Fuyun , Zhao Yixuan , Lin Danyang , Wu Laijun , Chen Bo , Song Xiaoguo
Published: June 2022

Severe porosity and coarse columnar grain are prone to be formed in the laser-MIG welded joint of aluminum alloy, deteriorating the strength and ductility seriously. In this study, the ultrasound was designed to assist the laser-MIG hybrid welding of aluminum alloy, and the influence of ultrasonic vibration on weld formation, porosity, and microstructure was investigated. The weld depth was increased from 3.6 mm to 4.2 mm when external ultrasound with the pressure of amplitude transformer (PAT) of 132 N was used, indicating that the penetration ability of hybrid heat sources to the welded plate could be improved. It was attributed to the dispersion effect of ultrasound on arc plasma in the laser channel. The porosity rate was reduced from 5.66–1.05% under PAT of 132 N, because of the increase in escape velocity of bubbles. Moreover, the columnar to equiaxed transformation (CET) of grain in the weld was promoted and the width of columnar grain zone was gradually reduced with the increasing ultrasonic energy, owing to the breaking effect of cavitation and the stirring effect of acoustic stream. As a result, lower porosity rate and finer grain size led to improvement of the microhardness and the strength of weld by ultrasound. The study provides more guidance on employing ultrasound to improve the quality of welded joints.
Switchable half-metallicity in A-type antiferromagnetic NiI2 bilayer coupled with ferroelectric In2Se3
Authors: Li Yanlu , Wang Yaping , Xu Xinguang , Zhao Xian , Ji Weixiao , Cao Qiang , Li Shengshi
Published: June 2022

Electrically induced and controlled half-metallicity or fully spin polarized current in antiferromagnet is of great significance for both fundamental research and practical application in spintronics. Here, by combining two-dimensional (2D) A-type antiferromagnetic (AFM) NiI2 bilayer (bi-NiI2) with ferroelectric (FE) In2Se3 with different thickness to construct van der Waals (vdW) heterostructure, we propose that the AFM half-metallicity is realizable and switchable in the bi-NiI2 proximate to In2Se3 bilayer (bi-In2Se3). The reversal of the electric polarization of the FE bi-In2Se3 successfully drives nonvolatile transition between half-metal and semiconductor for the AFM bi-NiI2. The mechanism of this intriguing phenomenon cooperatively stems from the energy band shift driven by the polarization field, and from the interfacial charge transfer. Besides, the easy magnetization axis of the bi-NiI2 is switched between the out-of-plane and in-plane directions for the two opposite polarization states. More interestingly, by introducing strain, the half-metallic behavior and magnetic anisotropy energy (MAE) of the bi-NiI2 in the heterostructure can be effectively manipulated. These findings provide not only a feasible strategy for nonvolatile electrical controlled half-metallicity in a 2D antiferromagnet, but also a promising platform for designing new advanced nanodevices.
Increased probability of hot and dry weather extremes during the growing season threatens global crop yields
Authors: Heino Matias , Kinnunen Pekka , Anderson Weston , Ray Deepak , Puma Michael J. , Varis Olli , Siebert Stefan , Kummu Matti
Published: June 2022

Although extreme weather events recur periodically everywhere, the impacts of their simultaneous occurrence on crop yields are globally unknown. In this study, we estimate the impacts of combined hot and dry extremes as well as cold and wet extremes on maize, rice, soybean, and wheat yields using gridded weather data and reported crop yield data at the global scale for 1980-2009. Our results show that co-occurring extremely hot and dry events have globally consistent negative effects on the yields of all inspected crop types. Extremely cold and wet conditions were observed to reduce crop yields globally too, although to a lesser extent and the impacts being more uncertain. Critically, we found that over the study period, the probability of co-occurring extreme hot and dry events during the growing season increased across all inspected crop types; wheat showing the largest, up to a six-fold, increase. Hence, our study highlights the potentially detrimental impacts that increasing climate variability can have on global food production.