162 research outputs found
FIG. 2 in A new species and a new record of the genus Phaeophyscia Moberg (Lecanorales, Physciaceae) from Pakistan supported by phenotypic and molecular phylogenetic analyses
No full textFIG. 2. — Phaeophyscia kaghanensis Niazi, Nadeem, Afshan & Khalid, sp. nov.: A, foliose thallus of type specimen (holo-, LAH[LAH37615]); B, apothecia; C, section of an apothecium; D, E, ascus; F, ascospores. Scale bars: A, 1 cm; B, 3 mm; C, 100 μm; D, 28 μm; E, 24 μm; F, 14 μm.Published as part of Niazi, Abdul Rehman, Afshan, Najam-ul-Sehar, Naseer, Arooj, Nadeem, Muhammad, Iftikhar, Fatima, Fayyaz, Iram, Ashraf, Asma, Imtiaz, Sawera, Fatima, Shahzadi Qamar & Khalid, Abdul Nasir, 2023, A new species and a new record of the genus Phaeophyscia Moberg (Lecanorales, Physciaceae) from Pakistan supported by phenotypic and molecular phylogenetic analyses, pp. 51-59 in Cryptogamie, Mycologie 20 (4) on page 55, DOI: 10.5252/cryptogamie-mycologie2023v44a4, http://zenodo.org/record/786720
An adaptive discrete Newton method for a regularization-free Bingham model
No full textDeveloping a numerical and algorithmic tool which correctly identifies unyielded regions in the yield stress fluid flow is a challenging task. Two approaches are commonly used to handle the singular behaviour at the yield surface, i.e. the Augmented Lagrangian approach and the regularization approach, respectively. Generally in the regularization approach for the resulting nonlinear and linear problems, solvers do not perform efficiently when the regularization parameter gets very small. In this work, we use a formulation introducing a new auxiliary stress [1]. The three field formulation of yield stress fluids corresponds to a regularization-free Bingham formulation. The resulting set of equations arising from the three field formulation is treated efficiently and accurately by a monolithic finite element method. The velocity and pressure are discretized by the higher order stable FEM pair Q_2⁄(P_1^disc ) and the auxiliary stress is discretized by the Q_2 element.
Furthermore, this problem is highly nonlinear and presents a big challenge to any nonlinear solver. We developed a new adaptive discrete Newton's method, which evaluates the Jacobian with the directional divided difference approach [2]. The step size in this process is an important key: We relate this size to the rate of the actual nonlinear reduction for achieving a robust adaptive Newton's method. The resulting linear subproblems are solved using a geometrical multigrid solver. We analyse the solvability of the problem along with the adaptive Newton method for Bingham fluids by doing numerical studies for different prototypical configurations, i.e. "Viscoplastic fluid flow in a channel" [2], "Lid Driven Cavity", "Flow around cylinder", and "Bingham flow in a square reservoir", respectively.
References
[1] A. Aposporidis, E. Haber, M. A. Olshanskii, A. Veneziani. A Mixed Formulation of the
Bingham Fluid Flow Problem: Analysis and Numerical Solution, Comput. Methods Appl. Mech. Engrg. 1 (2011), 2434–2446.
[2] A. Fatima, S. Turek, A. Ouazzi, M. A. Afaq. An Adaptive Discrete Newton Method for Regularization-Free Bingham Model, 6th ECCOMAS Young Investigators Conference 7th-9th July 2021, Valencia, Spain. doi: 10.4995/YIC2021.2021.12389
Biosynthesis and characterization of bacterial cellulose membranes presenting relevant characteristics for air/gas filtration
No full textFunding Information:
This work was supported by the Associate Laboratory LS4FUTURE which are financed by Portuguese national funds from the Fundação para a Ciência e Tecnologia (FCT/MCTES, Portugal) ( LA/P/0087/2020). Arooj Fatima acknowledges FCT for PhD grant reference 2021.07557. BD. The authors acknowledge Professor Vítor D. Alves, from Instituto Superior de Agronomia, Universidade de Lisboa , for the support in the analysis of membrane mechanical properties.
Publisher Copyright:
© 2023The production of bacterial cellulose has gained prominence in recent years as an alternative for the sustainable production of materials that might be used in diverse processes and applications. The present study discusses the possibility of producing tailored bacterial cellulose membranes in situ, that present relevant characteristics for potential use in air/gas filtration. Various cultivation processes and characterization studies were performed to ascertain the suitability of Komagataeibacter sp. FXV3, Komagataeibacter sp. NFXK3, and K. intermedius LMG 18909 bacterial strains to produce cellulose membranes with diverse properties. Subsequently, the bacterial cellulose films produced were freeze-dried to obtain stable membranes, and extensively characterized for their physicochemical properties. The results obtained showed that different strains enabled the synthesis of membranes with distinctive morphological properties. Moreover, the different carbon sources and ethanol concentrations employed in the cultivation media led to modifications in the cellulose membranes produced by the different Komagataeibacter strains, which further impacted membrane morphology and, ultimately, gas filtration behavior. All the synthesized membranes were fully characterized, showing adequate mechanical properties, and tested for permeance of N2, CO2 and O2, opening perspectives for their use in air/gas filtration.publishersversionpublishe
An integrated architecture for semantic search
No full textmeaningful manner such that software agents can search, reason with and manipulate this
data based on an understanding of its semantics. Accessing structured data from Linked
Open Datasets currently requires the use of formal query languages (such as SPARQL) which
poses significant difficulties for the end users.
One way to solve this problem is to provide a Natural Language Interface (NLI) to query
semantic data. The author undertook a comprehensive literature survey of existing semantic
search tools and performed a critical analysis to identify their strengths and weaknesses.
Although some of the existing tools support natural language, they are limited in their
techniques for query processing, result ranking, result readability and ease of integration
with other search tools. Based upon this analysis, this research proposes a new architecture
framework called SIRF (Semantic Information Retrieval Framework) for semantic search to
address these shortcomings.
This thesis provides a complete overview of the proposed framework, including: the
research challenges it addresses; its architecture; the techniques to map user queries to
SPARQL queries and to rank domains based on ontology concepts; and the evaluation of the
proposed system through a prototype. Evaluation of the prototype demonstrated the validity
of the approach. However the quality of resulting queries (and consequently retrieved
answers) depended upon the accuracy of the NLP parsers invoked by the prototype. Syntactically
well structured NL queries were correctly parsed, yielding better formed SPARQL
queries. Less structured NL queries performed poorly. As the framework is not tied to any
particular parser, result quality can be improved by utilising better parsers as they become
available.
The author believes that this work can be employed by a variety of end-user applications
that wish to utilise structured data
An integrated architecture for semantic search
No full textmeaningful manner such that software agents can search, reason with and manipulate this
data based on an understanding of its semantics. Accessing structured data from Linked
Open Datasets currently requires the use of formal query languages (such as SPARQL) which
poses significant difficulties for the end users.
One way to solve this problem is to provide a Natural Language Interface (NLI) to query
semantic data. The author undertook a comprehensive literature survey of existing semantic
search tools and performed a critical analysis to identify their strengths and weaknesses.
Although some of the existing tools support natural language, they are limited in their
techniques for query processing, result ranking, result readability and ease of integration
with other search tools. Based upon this analysis, this research proposes a new architecture
framework called SIRF (Semantic Information Retrieval Framework) for semantic search to
address these shortcomings.
This thesis provides a complete overview of the proposed framework, including: the
research challenges it addresses; its architecture; the techniques to map user queries to
SPARQL queries and to rank domains based on ontology concepts; and the evaluation of the
proposed system through a prototype. Evaluation of the prototype demonstrated the validity
of the approach. However the quality of resulting queries (and consequently retrieved
answers) depended upon the accuracy of the NLP parsers invoked by the prototype. Syntactically
well structured NL queries were correctly parsed, yielding better formed SPARQL
queries. Less structured NL queries performed poorly. As the framework is not tied to any
particular parser, result quality can be improved by utilising better parsers as they become
available.
The author believes that this work can be employed by a variety of end-user applications
that wish to utilise structured data
Real-Time Implementation of Spectrum Sensing Techniques in Cognitive Radios
No full textWireless communication requirements of higher sampling frequencies and bandwidth are ever increasing. For this purpose, exploitation of underutilized spectrum bands was one the challenging research targets. Cognitive Radio (CR) is a promising solution to overcome the “limited bandwidth” issue. Software defined radio (SDR) is the enabler of CR. The aim of the thesis is to adopt the vacant TV channels for secondary users. Spectrum sensing prototype has been proposed to detect TV white space (TVWS). The prototype has been developed using Universal Software Radio Peripheral (USRP) and examined to sense TVWS in the real time world. The conducting analysis of obtained measurements showed the state of unoccupied spectrum bands in the UHF band ranges from 500 MHz to 698 MHz in the urban area ofWindsor, Ontario, Canada. Two different spectrum sensing techniques namely, the energy detector, and pilot-tone detector were employed to get the result with minimum computational complexity. Experiments show that the presence of incumbent users can be easily detected using the spectrum sensing techniques mentioned in the thesis. The experimental results have demonstrated the validity of the proposed prototyp
Phaeophyscia microspora Aptroot & Schumm
No full textPhaeophyscia microspora Aptroot & Schumm (Fig. 3) Virtuelles Herbarium de Flechtengattungen Hyperphyscia, Paeophyscia, Physcia und Physconia: 193 (Schumm & Aptroot 2019). SPECIMENS EXAMINED. — Pakistan. Margalla Hills, Islamabad, 1604 m alt., on tree bark, 33°41’35”N, 73°03’50”E, 09.IV.2019, A. Ashraf, K. Habib & M. Usman, T5-02 (LAH[LAH37622]; GenBank[OQ024193]); Azad Jammu and Kashmir, District Bagh, 33.9259°N, 73.7810°E, 4734 m alt., on tree bark, 10.XI.2021, A. Naseer, B-04 (LAH[LAH37624]; GenBank[OQ073895]); Azad Jammu and Kashmir, District Bagh, 33°55’33.24”N, 73°46’51.6”E, 4734 m alt., on tree bark, 12.XI.2021, A. Naseer, B-05 (LAH[LAH37625]; GenBank[OQ073896]); Khyber Pakhtunkhwa, Kaghan Valley, Shogran, 34°64’N, 73°46’E, 2362 m alt., on bark, 24.VIII.2021, A. R. Niazi & M. Nadeem, SN-1 (LAH [LAH37618]; GenBank[OP933725]); Khyber Pakhtunkhwa, Kaghan Valley, Siri Paya, 33°71’N, 78°08’E, 3000 m alt., on tree bark, 26.VIII.2022, A. R. Niazi & M. Nadeem, BK-14 (LAH [LAH37617]; GenBank[OP933722]). CHEMISTRY. — Thallus K-, C-, KC-, P-; no lichen substance detected by TLC. HABITAT AND DISTRIBUTION. — Pakistani collections of this species are from humid to moist temperate, coniferous forest and scrub forest. The specimens were found on tree bark. The maximum daily temperature of the Himalaya region varies around 30-32°C during the summer, the average winter temperature is 4°C, while Margala Hills have an average maximum temperature of 34.3°C and minimum of 3.4°C with an average rainfall of 1200 mm per year. DESCRIPTION Thallus Foliose, epiphloeodal, rust grey to pale grey, remaining unchanged when wet, loosely attached to substratum, very variable in size, 2-4 cm in diam. Lobes Densely, dichotomously or irregularly branched, without pruina, lobe tips creamy white, flat to strongly convex, imbricate, usually upturned near the tips, 0.5-1.5 mm wide. Soralia and isidia Absent. Cortex Dark brown, paraplectenchymatous, 18-23 µm thick. Algal layer 28-34 µm thick. Photobiont cells Globose, 8-13 µm in diam. Medulla White. Lower surface Black, usually becoming pale to dark grey towards lobe tips, rhizinate. Rhizines Dense, black, simple, 1.3-2.5 mm long. Lower cortex Paraplectenchymatous, dark brown, 18-30 µm thick. Apothecia Abundant, usually present, 1.5-3 mm in diam., stipitate to very shortly stipitate, the margin entire or becoming regularly crenate, with prominent cortical hairs, epruinose or slightly pruinose. Disc Charcoal black, shiny, flat to strongly concave or sometimes convex. Margins Prominent, creamy to pale white. Epihymenium Light brown to orange, 18-24 µm. Hymenium Hyaline to creamy, 70-90 µm. Hypothecium Creamy white, 22-28 µm. Ascus Cylindrical to clavate, 45-55 ×12-14 µm. Ascospores Dark brown, ellipsoid, Physcia - type, 16-20 ×7.5-9 µm. Paraphyses Hyaline, branched and anastomosing, 1.7-2.8µm thick, wider at the apex, 3-4 µm thick. Pycnidia Not found.Published as part of Niazi, Abdul Rehman, Afshan, Najam-ul-Sehar, Naseer, Arooj, Nadeem, Muhammad, Iftikhar, Fatima, Fayyaz, Iram, Ashraf, Asma, Imtiaz, Sawera, Fatima, Shahzadi Qamar & Khalid, Abdul Nasir, 2023, A new species and a new record of the genus Phaeophyscia Moberg (Lecanorales, Physciaceae) from Pakistan supported by phenotypic and molecular phylogenetic analyses, pp. 51-59 in Cryptogamie, Mycologie 20 (4) on pages 56-57, DOI: 10.5252/cryptogamie-mycologie2023v44a4, http://zenodo.org/record/786720
Phaeophyscia kaghanensis Niazi, Nadeem, Afshan & Khalid 2023, sp. nov.
No full textPhaeophyscia kaghanensis Niazi, Nadeem, Afshan & Khalid, sp. nov. (Fig. 2) The taxon is characterized by its greyish white to grey thallus, absence of asexual diaspores or cortical hairs, flat to slightly concave lobes, white medulla, black lower surface, large, Physcia-type ascospores of 24-30× 12-17 µm, and absence of secondary substances. HOLOTYPE. — Pakistan. Azad Jammu and Kashmir, Garhi Dupatta, 34°36’N, 73°35’E, 817 m alt., on tree bark, 2.X.2021, N. S. Afshan & A. R. Niazi, CKR-22 (holo-, LAH [LAH37615]; GenBank[OP933723]). ADDITIONAL SPECIMEN EXAMINED. — Pakistan. Khyber Pakhtunkhwa, Kaghan Valley, Sharan, 34°30’N, 73°18’E, 2500 m alt., on tree bark, 22.VIII.2022, N. S. Afshan & A. R. Niazi, KA-17 (LAH [LAH 37616]; GenBank[OP 933724]). ETYMOLOGY. — The specific epithet ‘kaghanensis’ (Latin) refers to the type locality of Kaghan Valley. CHEMISTRY. — Thallus K-, C-, KC-, P-; no lichen substance detected by TLC. HABITAT AND DISTRIBUTION. — The known collections of the new species are from moist temperate, coniferous forest in the Himalaya in Azad Jammu and Kashmir. The specimens were found on siliceous rock. The forest is dominated by species such as Pinus roxburghii Sarg., Pyrus pashia L., Quercus oblongata D.Don and Q. glauca Thunb. The maximum daily temperature of the region varies around 30-32°C during the summer, the average winter temperature is 4°C, and there is moderate rainfall. MYCOBANK. — MB846997. DESCRIPTION Thallus Foliose, epiphloeodal, greyish white to grey, remaining unchanged when wet, loosely attached to substratum, 3-5 cm in diam., more or less circular in outline. Lobes Densely, dichotomously or irregularly branched, without pruina, lobe tips greyish-white, flat to slightly concave, imbricate, usually upturned near the tips, 0.8-2.5 mm wide. Soralia and isidia Absent. Upper surface Dark brown, paraplectenchymatous, 20-25 µm thick. Algal layer 30-35 µm thick. Photobiont cells Globose, 10-15 µm in diam. Medulla White. Lower surface Black, usually becoming pale to dark grey towards lobe tips, not rhizinate. Rhizines Absent. Lower cortex Paraplectenchymatous, dark brown, 28-35 µm thick. Apothecia Frequent, usually present, 2.5-4 mm in diam., stipitate, lacking cortical hairs, epruinose. Disc Chocolate brown to black, dull, epruinose, flat to strongly convex. Margins Prominent, creamy to pale white. Epihymenium Light brown to brownish orange, 13-17 µm. Hymenium Hyaline, 90-110 µm. Hypothecium Hyaline, 25-35 µm. Ascus Cylindrical to clavate, 70-83 × 22-28 µm. Ascospores Dark brown, ellipsoid, Physcia - type, 24-30× 12-17µm. Paraphyses Hyaline, branched and anastomosing, 2-3 µm thick, wider at the apex, 4-5 µm thick. Pycnidia Not found.Published as part of Niazi, Abdul Rehman, Afshan, Najam-ul-Sehar, Naseer, Arooj, Nadeem, Muhammad, Iftikhar, Fatima, Fayyaz, Iram, Ashraf, Asma, Imtiaz, Sawera, Fatima, Shahzadi Qamar & Khalid, Abdul Nasir, 2023, A new species and a new record of the genus Phaeophyscia Moberg (Lecanorales, Physciaceae) from Pakistan supported by phenotypic and molecular phylogenetic analyses, pp. 51-59 in Cryptogamie, Mycologie 20 (4) on pages 52-56, DOI: 10.5252/cryptogamie-mycologie2023v44a4, http://zenodo.org/record/786720
Machine learning model for predicting hepatocellular carcinoma in Hepatitis C patients
No full textAn estimated 58 million people suffer from chronic Hepatitis C virus around the world, while substantial evidence indicates that patients with Hepatitis C virus are at 17 times larger risk of developing Liver Cancer (Hepatocellular Carcinoma). Research has been carried out to predict hepatitis C and liver cancer at different stages in patients. In this research, we proposed the Classification model AdaBoost with Decision Tree as its base model to be trained and tested on patient dataset. The dataset contains records of clinical indicators and was acquired from the University of California Irvine Machine Learning Repository. The preparation of the dataset was done using balancing techniques i.e. SMOTE, it was encoded using Ordinal Encoding. The hyperparameters of AdaBoost model was tuned manually to find the most optimal combination. AdaBoost Classification Model achieved a 92.68% accuracy, and the AUROC of 0.97. The precision and recall differ for each class, “healthy” individuals were classified with a precision of 98% and a recall of 99% while patients with “Cirrhosis” (irreversible scarring of liver due to a tumor) were classified with 86% precision and 67% recall. The research concluded that machine learning has efficient applications in predicting diseases. Moreover, the clinical indicators mentioned in previous studies have proven to be vital in the prediction of HCC (liver cancer) however it is advised that, in future a larger dataset may be acquired to overcome any potential biases in the predictions. The current program successfully distinguishes between patients at different stages of HCC and HCV and can be further adapted to build decision systems to aid diagnosis
Monolithic Newton-Multigrid Solver for Multiphase Flow Problems with Surface Tension
No full text[EN] We have developed a monolithic Newton-multigrid solver for multiphase flow problems which solves velocity, pressure and interface position simultaneously. The main idea of our work is based on the formulations discussed in [1], where it points out the feasibility of a fully implicit monolithic solver for multiphase flow problems via two formulations, a curvature-free level set approach and a curvature-free cutoff material function approach. Both formulations are fully implicit and have the advantages of requiring less regularity, since neither normals nor curvature are explicitly calculated, and no capillary time restriction. Furthermore, standard Navier-Stokes solvers might be used, which do not have to take into account inhomogeneous force terms. The reinitialization issue is integrated with a nonlinear terms within the formulations.The nonlinearity is treated with a Newton-type solver with divided difference evaluation of the Jacobian matrices. The resulting linearized system inside of the outer Newton solver is a typical saddle point problem which is solved using the geometrical multigrid with Vanka-like smoother using higher order stable FEM pair for velocity and pressure and for all other variables. The method is implemented into an existing software packages for the numerical simulation of multiphase flows (FeatFlow). The robustness and accuracy of this solver is tested for two different test cases, i.e. static bubble and oscillating bubble, respectively [2].Muhammad Aaqib Afaq would like to thank Erasmus Mundus INTACT project, funded by the European Union as part of the Erasmus Mundus programme and the National University of Sciences and Technology (NUST) for their financial support. The authors also acknowledge the support by LS3 and LiDO3 team at ITMC, TU Dortmund University.Afaq, MA.; Turek, S.; Ouazzi, A.; Fatima, A. (2022). Monolithic Newton-Multigrid Solver for Multiphase Flow Problems with Surface Tension. En Proceedings of the YIC 2021 - VI ECCOMAS Young Investigators Conference. Editorial Universitat Politècnica de València. 190-199. https://doi.org/10.4995/YIC2021.2021.12390OCS19019
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