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Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7482
Author(s):  
Mingxian Wang ◽  
Xiangji Dou ◽  
Ruiqing Ming ◽  
Weiqiang Li ◽  
Wenqi Zhao ◽  
...  

Refracturing treatment is an economical way to improve the productivity of poorly or damaged fractured horizontal wells in tight reservoirs. Fracture reorientation and fracture face damage may occur during refracturing treatment. At present, there is still no report on the rate decline solution for refractured horizontal wells in tight reservoirs. In this work, by taking a semi-analytical method, traditional rate decline and Blasingame-type rate decline solutions were derived for a refractured horizontal well intercepted by multiple reorientation fractures with fracture face damage in an anisotropic tight reservoir. The accuracy and reliability of the traditional rate decline solution were verified and validated by comparing it with a classic case in the literature and a numerical simulation case. The effects of fracture reorientation and fracture face damage on the rate decline were investigated in depth. These investigations demonstrate that fracture face damage is not conducive to increasing well productivity during the early flow period and there is an optimal matching relationship between the principal fracture section angle and permeability anisotropy, particularly for the reservoirs with strong permeability anisotropy. The fracture length ratio and fracture spacing have a weak effect on the production rate and cumulative production while the fracture number shows a strong influence on the rate decline. Furthermore, multifactor sensitivity analysis indicates that fracture conductivity has a more sensitive effect on well productivity than fracture face damage, implying the importance of improving fracture conductivity. Finally, a series of Blasingame-type rate decline curves were presented, and type curve fitting and parameter estimations for a field case were conducted too. This work deepens our understanding of the production performance of refractured horizontal wells, which helps to identify reorientation fracture properties and evaluate post-fracturing performance.


HPB ◽  
2021 ◽  
Author(s):  
Marcello Di Martino ◽  
Stijn Van Laarhoven ◽  
Benedetto Ielpo ◽  
Jose Manuel Ramia ◽  
Alba Manuel-Vázquez ◽  
...  

2021 ◽  
Vol 15 (3) ◽  
pp. 1435-1451
Author(s):  
Nathan Maier ◽  
Florent Gimbert ◽  
Fabien Gillet-Chaulet ◽  
Adrien Gilbert

Abstract. On glaciers and ice sheets, identifying the relationship between velocity and traction is critical to constrain the bed physics that controls ice flow. Yet in Greenland, these relationships remain unquantified. We determine the spatial relationship between velocity and traction in all eight major drainage catchments of Greenland. The basal traction is estimated using three different methods over large grid cells to minimize interpretation biases associated with unconstrained rheologic parameters used in numerical inversions. We find the relationships are consistent with our current understanding of basal physics in each catchment. We identify catchments that predominantly show Mohr–Coulomb-like behavior typical of deforming beds or significant cavitation, as well as catchments that predominantly show rate-strengthening behavior typical of Weertman-type hard-bed physics. Overall, the traction relationships suggest that the flow field and surface geometry of the grounded regions in Greenland is mainly dictated by Weertman-type hard-bed physics up to velocities of approximately 450 m yr−1, except within the Northeast Greenland Ice Stream and areas near floatation. Depending on the catchment, behavior of the fastest-flowing ice (∼ 1000 m yr−1) directly inland from marine-terminating outlets exhibits Weertman-type rate strengthening, Mohr–Coulomb-like behavior, or is not confidently resolved given our methodology. Given the complex basal boundary across Greenland, the relationships are captured reasonably well by simple traction laws which provide a parameterization that can be used to model ice dynamics at large scales. The results and analysis serve as a first constraint on the physics of basal motion over the grounded regions of Greenland and provide unique insight into future dynamics and vulnerabilities in a warming climate.


2021 ◽  
Vol 12 ◽  
Author(s):  
Jian Guo ◽  
Min Zhang ◽  
Dan Qiao ◽  
Hui Shen ◽  
Lili Wang ◽  
...  

Candida parapsilosis complex is one of the most common non-albicans Candida species that cause candidemia, especially invasive candidiasis. The purpose of this study was to evaluate the antifungal susceptibilities of both colonized and invasive clinical C. parapsilosis complex isolates to 10 drugs: amphotericin (AMB), anidulafungin (AFG), caspofungin (CAS), micafungin (MFG), fluconazole (FLZ), voriconazole (VRZ), itraconazole (ITZ), posaconazole (POZ), 5-flucytosine (FCY), and isaconazole (ISA). In total, 884 C. parapsilosis species complex isolates were gathered between January 2005 and December 2020. C. parapsilosis, Candida metapsilosis, and Candida orthopsilosis accounted for 86.3, 8.1, and 5.5% of the cryptic species, respectively. The resistance/non-wild-type rate of bloodstream C. parapsilosis to the drugs was 3.5%, of C. metapsilosis to AFG and CAS was 7.7%, and of C. orthopsilosis to FLZ and VRZ was 15% and to CAS, MFG, and POZ was 5%. The geometric mean (GM) minimum inhibitory concentrations (MICs) of non-bloodstream C. parapsilosis for CAS (0.555 mg/L), MFG (0.853 mg/L), FLZ (0.816 mg/L), VRZ (0.017 mg/L), ITZ (0.076 mg/L), and POZ (0.042 mg/L) were significantly higher than those of bloodstream C. parapsilosis, for which the GM MICs were 0.464, 0.745, 0.704, 0.015, 0.061, and 0.033 mg/L, respectively (P < 0.05). The MIC distribution of the bloodstream C. parapsilosis strains collected from 2019 to 2020 for VRZ, POZ, and ITZ were 0.018, 0.040, and 0.073 mg/L, significantly higher than those from 2005 to 2018, which were 0.013, 0.028, and 0.052 mg/L (P < 0.05). Additionally, MIC distributions of C. parapsilosis with FLZ and the distributions of C. orthopsilosis with ITZ and POZ might be higher than those in Clinical and Laboratory Standards Institute studies. Furthermore, a total of 143 C. parapsilosis complex isolates showed great susceptibility to ISA. Overall, antifungal treatment of the non-bloodstream C. parapsilosis complex isolates should be managed and improved. The clinicians are suggested to pay more attention on azoles usage for the C. parapsilosis complex isolates. In addition, establishing the epidemiological cutoff values (ECVs) for azoles used in Eastern China may offer better guidance for clinical treatments. Although ISA acts on the same target as other azoles, it may be used as an alternative therapy for cases caused by FLZ- or VRZ-resistant C. parapsilosis complex strains.


TEM Journal ◽  
2020 ◽  
pp. 1088-1093
Author(s):  
Stepan Chalupa ◽  
Martin Petricek

Understanding customer behaviour is an essential activity for hotel marketers and revenue managers. This article presents the statistical approach based on the data mining techniques focused on the extraction of valuable insight from big data. Using Two-Step Clustering, four major customers segments were identified, including their characteristics. Their description based on the booked room type, rate plan, booking window, net average room rate and length of stay can help the manager to plan better their activities.


2020 ◽  
Author(s):  
Scott A. Keith ◽  
Cassandra Bishop ◽  
Samantha Fallacaro ◽  
Brooke M. McCartney

ABSTRACTPerturbations to animal-associated microbial communities (the microbiota) have deleterious effects on various aspects of host fitness, including dysregulated energy metabolism. However, the molecular processes underlying these microbial impacts on the host are poorly understood. In this study, we identify a novel connection between the microbiota and the neuronal factor Arc1 that affects metabolism and development in Drosophila. We find that Arc1 exhibits tissue-specific microbiota-dependent expression changes, and that flies bearing a null mutation of Arc1 complete larval development at a dramatically slowed rate compared to wild-type animals. In contrast, monoassociation with a single Acetobacter sp. isolate was sufficient to enable Arc1 mutants to develop at a wild-type rate. These developmental phenotypes are highly sensitive to composition of the larval diet, suggesting the growth rate defects of GF flies lacking Arc1 reflect metabolic dysregulation. Additionally, we show that pre-conditioning the larval diet with Acetobacter sp. partially accelerates Arc1 mutant development, but live bacteria are required for the full growth rate promoting effect. Finally, GF Arc1 mutants display multiple traits consistent with reduced insulin signaling activity that are reverted by association with Acetobacter sp., suggesting a potential mechanism underlying the microbe-dependent developmental phenotypes. Our results reveal a novel role for Arc1 in modulating insulin signaling, metabolic homeostasis, and growth rate that is specific to the host’s microbial and nutritional environment.SUMMARYDrosophila Arc1 exhibits microbiota-dependent, tissue-specific differential expression, mitigates the impacts of germ-free rearing on insulin signaling and growth rate, but is dispensable for metabolic homeostasis in Acetobacter-colonized flies.


2020 ◽  
Author(s):  
Katherine Turner ◽  
Richard G. Williams ◽  
Anna Katavouta ◽  
David J. Beerling

<p>Unlike historical carbon emissions, which have been driven by economics and politics, climate engineering methods must be scientifically assessed, with consideration as to the type, rate, and total amount implemented. Temperatures reductions from carbon dioxide removal have been found to be proportional to the cumulative amount of carbon removed.  Climate engineering “co-benefits”, such as reduced ocean acidification, may also occur and should be considered when optimising an engineered climate solution. In this study we examine the sensitivities of climate engineering to its implementation, focussing on the effects of its time of onset and rate of carbon capture or enhanced weathering, as well as  background emissions and ocean physics.</p><p>We use two simple coupled models– a Gnanadesikan-style coupled atmosphere-ocean model and the intermediate-complexity Earth system model GENIE – with idealised setups for negative emissions through either carbon capture and sequestration, enhanced weathering, or a combination. The inclusion of enhanced weathering provides insight as to how changes in ocean carbonate chemistry may impact climate, both in terms of temperature and pH changes. We have created ensembles in which the timing, rate, background emissions scenario, and model physics of the model vary and use these ensembles to understand how these decisions may impact the efficacy of climate engineering.</p><p>We find that the effectiveness of climate engineering is dependent upon the background carbon emissions and the choice of climate engineering. Carbon capture reduces surface average temperature more per PgC captured than enhanced weathering, and both are more effective under low emissions scenarios. Additionally, background emissions determine how the impact of climate engineering is realised: under high emissions, earlier implementation of climate engineering results in faster temperature mitigation, although the end state is independent of the onset. When considering reductions in ocean acidification, we find that the alkalinity flux in our enhanced weathering experiments leads to a higher pH than for carbon capture, as well as the pH signals being less dependent on the timing. Thus, the timing and pathway of the climate engineering is important in terms of the resulting averted warming and acidification, though the final equilibrium is still effectively determined by the cumulative carbon budget.</p>


2020 ◽  
pp. 104-109
Author(s):  
Vladislav Leonidovich Nezevak ◽  
◽  
Svyatoslav Sergeevich Samolinov ◽  

The paper considers issues of increasing capacity on «bottleneck» sections of direct current railways by means of application of electric power accumulators. Selection of electric power accumulators location is carried out with the consideration for grading of track on a section, specific recuperation, dominance of traffic type, rate of electric rolling stops, mode of feeding of intersubstational zones. When determining power consumption and capacity of electric power accumulators a depth of discharge that affects a service life and a state of charge graph that depends on a selected characteristic of charging rate are considered. The procedure of assessing the influence of electric power accumulator operation on capacity is considered on the example of one of the railway sections.


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