96 research outputs found
Analysis of electron-atom and electron-molecule collisions
The relativistic R-matrix method is used to calculate elastic and inelestic cross sections for electrons incident on caesium atoms with energies from 0 to 3 eV. In addition to the total cross sections, results are presented on the differential cross section, σ, and the spin polarization, Py, of the scattered electrons as a function of energy at eight scattering angles (10°, 30°, 50°, 70°, 90°, 110°, 130°, 150°). Also the differential cross section, spin polarization and the left-right asymmetry function, As, are calculated as a function of the scattering angles at a number of chosen values of energies. The calculation reveals a wealth of resonances around 2p1/2 and 2p3/2 thresholds. The resonances are
analysed in detail and their role in the scattering process is discussed.
The density matrix formalism is used to derive expressions for the Stokes' Parameters to describe the state of the photons emitted in electron-atom collision experiment. Numerical results for the Stokes
Parameters of the light emitted in the decay 6p 2p1/2,3/2 -> 6s 2S1/2 in atomic caesium after electron impact excitation are presented and compared with the available measurements. These results show what effects can be expected and may be useful for the planning of future experiments.
The angular distribution and the integrated cross sections have been calculated at incident electron energies 20, 25 and 30 eV, in e-N2 scattering. The calculations are based on the use of numerical basis functions in the R-Matrix method, and exchange and polarization effects are included. Also variation of the mixing parameter, between p- and f- partial waves and the individual eigenphases with the internuclear distance are presented. The mixing parameter has shown to be a rapidly varying function of the internuclear distance contradicting the assumption made by Chang (1977)
SOCIJALNO RAČUNOVODSTVO I IZVJEŠĆIVANJE O DRUŠTVENOJ ODGOVORNOSTI U JORDANSKIM KORPORACIJAMA NA AMMANSKOJ BURZI
This study examines practice of social accounting and the reporting of social responsibility in the industrial Jordanian companies listed in Amman Stock Exchange. As operations of industrial companies have significant impact on the society, they should be accountable to the environment, and members of societies in which they operate. The method adopted to figure out the state of current social accounting and reporting practices was carried out by analyzing the annual reports of 30 randomly selected Jordanian industrial companies for the year 2016. The study found that 73% of industrial companies in Jordan are disclosing their activities of social responsibility in the annual reports. This study also found that 50% of these companies use the director’s reports as the main outlet for disclosing their activities related to social responsibility, 36% companies use the corporate social responsibility report and finally 14% are use the notes or schedule to financial statement to inform general people about their commitment to social responsibility. The study recommended that as there are many types and techniques of reporting, the Jordanian securities commission, as a government regulatory entity, should work on establishing uniformity for disclosing social accounting reports, and the outlet for such disclosure should be clearly specified.Ovaj rad istražuje praksu socijalnog računovodstva i izvješćivanja o društvenoj odgovornosti u jordanskim korporacijama na ammanskoj burzi. S obzirom da aktivnosti korporacija imaju značajan utjecaj na društvo, one trebaju biti odgovorne spram okoline i članova društva u kojima djeluju. Kako bi se utvrdilo stanje socijalnog računovodstva i izvješćivanja, provedena je analiza godišnjih izvješća 30 slučajno odabranih jordanskih korporacija za 2016. godinu. Istraživanje je pokazalo kako 73% korporacija u Jordanu iskazuju svoje društveno odgovorne aktivnosti u godišnjim izvješćima. Kako bi informirali o njihovoj predanosti društvenoj odgovornosti, 50% tih korporacija koriste izvještaje menadžmenta, 36% korporacija koristi izvješće o društvenoj odgovornosti poduzeća, a 14% koristi bilješke uz financijske izvještaje. S obzirom da postoje mnoge tehnike izvještavanja, zaključak je kako jordanska komisija za vrijednosne papire, kao regulatorno tijelo državne vlasti, treba raditi na uspostavljanju jedinstvenih izvještaja o socijalnom računovodstvu
Prediction of Splitting Tensile Strength of Self-Compacting Recycled Aggregate Concrete Using Novel Deep Learning Methods
[EN] The composition of self-compacting concrete (SCC) contains 60–70% coarse and fine aggregates, which are replaced by construction waste, such as recycled aggregates (RA). However, the complexity of its structure requires a time-consuming mixed design. Currently, many researchers are studying the prediction of concrete properties using soft computing techniques, which will eventually reduce environmental degradation and other material waste. There have been very limited and contradicting studies regarding prediction using different ANN algorithms. This paper aimed to predict the 28-day splitting tensile strength of SCC with RA using the artificial neural network technique by comparing the following algorithms: Levenberg–Marquardt (LM), Bayesian regularization (BR), and Scaled Conjugate Gradient Backpropagation (SCGB). There have been very limited and contradicting studies regarding prediction by using and comparing different ANN algorithms, so a total of 381 samples were collected from various published journals. The input variables were cement, admixture, water, fine and coarse aggregates, and superplasticizer; the data were randomly divided into three sets—training (60%), validation (10%), and testing (30%)—with 10 neurons in the hidden layer. The models were evaluated by the mean squared error (MSE) and correlation coefficient (R). The results indicated that all three models have optimal accuracy; still, BR gave the best performance (R = 0.91 and MSE = 0.2087) compared with LM and SCG. BR was the best model for predicting TS at 28 days for SCC with RA. The sensitivity analysis indicated that cement (30.07%) was the variable that contributed the most to the prediction of TS at 28 days for SCC with RA, and water (2.39%) contributed the least.S
Experimental Research on Mechanical and Permeability Properties of Nylon Fiber Reinforced Recycled Aggregate Concrete with Mineral Admixture
[EN] Plain concrete’s major two drawbacks are its low tensile strength and high carbon footprint. Joint adding of fibers and recycled/waste materials in concrete might assist to resolve these problems. In the present study, a novel technique is planned to improve the recycled aggregate concrete (RAC) mechanical behavior and durability performance by joint incorporation of silica fume (SF) and nylon fibers (NF). In this research paper, different properties of concrete samples are examined for example flexural strength, compressive strength, split tensile strength, penetration of chloride ions, acid resistance, and water absorption. It was noted that adding nylon fibers as individual components enhances the recycled aggregate concrete mechanical characteristics and resistance to acid exposure. The inclusion of nylon fibers improved the behavior of the recycled aggregate concrete; however, it also increased the chloride penetration and water absorption by only 18% and 8% respectively. Up to 26% of mechanical strength of concrete was improved when silica fume was added in comparison to reference concrete, silica fume also assisted in controlling the loss of durability because of adding recycled aggregate concrete and nylon fibers. Silica fume improved the bond between binder matrix and nylon fibers. The study revealed that the combination of 50% RCA, 0.5% nylon fibers and 20% silica fume are optimum for the joint incorporation into concrete that can assist in developing sustainable, durable, and ductile recycled aggregate fiber reinforced concrete.S
Characteristics of high-performance steel fiber reinforced recycled aggregate concrete utilizing mineral filler
[EN] In current state of the World, the pollution is increasing very fast. One of its major reason is the
production of huge quantity of cement which causes outflow of CO2 into the environment and
land dumping of construction and demolition waste which leads to the land pollution. In order to
address this major issue, it is important to decrease the utilization of cement by substituting the
cement with by product such as slag and using recycled aggregates as a replacement of natural
aggregates. This research aimed to utilize evaluate the performance of sustainable high-
performance concrete reinforced with steel fibers which is produced with recycled aggregate.
Crushed stone aggregates are supplanted with recycled aggregates extracted from source concrete
that had compression strength of 45 MPa and 85 MPa at proportions of 50% and 100%. Steel
fibers are used at 2% to produce high-performance concrete, and in a few of the mixtures, the
cement was substituted with granulated blast furnace slag. In addition to mechanical perfor-
mance, the durability properties, i.e., electrical resistivity, drying shrinkage, and water absorp-
tion, of concrete blends were examined. The test outcomes show that high-performance concrete
with the required characteristics can be developed utilizing recycled aggregates extracted from
source concrete of high strength. The inclusion of double hooked end steel fibers considerably
improves the mechanical characteristics of RAC. Concrete formed with high-quality recycled
concrete aggregates and mixes comprising granulated blast furnace slag (GBFS) and double
hooked end (DHE) steel fibers shows decreased drying shrinkage and water absorption in com-
parison to normal concrete. The outcomes of the present study assist in making of suitable high-
performance concrete which is sustainable and budget friendly.SIt F. M. Mukhtar would like to acknowledge the support of King Fahd University of Petroleum & Minerals (KFUPM
Treatment and Disease-related Complications in Multiple Myeloma
Multiple myeloma is a clonal plasma cell neoplasm that is mainly characterized by anemia, renal insufficiency, hypercalcemia, and bone destruction. Since 1990, there is an increase in the incidence of myeloma globally by 126%. However, due to the presence of the new therapeutic agents such as proteasome inhibitors, immunomodulatory drugs, Chimeric antigen receptor T-cell therapy, bispecific antibodies, bisphosphonates, corticosteroids, melfulfen, iberdomide, cyclophosphamide, plerixafor, melphalan chemotherapy, nuclear transport inhibitor, and monoclonal antibodies, as well as upfront autologous and allogeneic hematopoietic cell transplantation in eligible patients, a decline in the age-standardized mortality rate has been seen. This leads to higher survival rates of patients with multiple myeloma in the last 15 years, and hence, patients with multiple myeloma for 10–15 years are no longer rare. However, it has been observed that even though the treatment goal was to prevent end-organ damage, improve or maintain quality of life (QoL), and achieve long-term disease-free survival; thus, new treatments have converted myeloma into a chronic disease, such as peripheral neuropathy (PN), venous thromboembolism, and cardiac toxicity. Notably, most patients remain on continuous treatment for extended time periods, which leads to various complications. Hence, management of immediate and late complications from disease and treatment is a critical component of survivorship care in myeloma
Mechanical properties and durability assessment of nylon fiber reinforced self-compacting concrete
[EN] The higher paste volume in Self Compacting Concrete (SCC) makes it susceptible to have a higher creep coefficient
and cracking and has brittle nature. This brittle nature of concrete is unacceptable for any construction industry. The
addition of fibers is one of the most prevalent methods to enhance the ductile and tensile behavior of concrete. Fibers
reduce the cracking phenomena and improve the energy absorption capacity of the structure. Conversely, the addition
of fibers has a negative impact on the workability of fresh concrete. In this research work, a detailed investigation of
the influence of Nylon fibers (NFs) on fresh properties, durability, and mechanical properties of SCC was carried out.
NFs were added into concrete mixes in a proportion of 0.5%, 1%, 1.5%, and 2% by weight of cement to achieve the
research objectives. Durability assessment of modified SCC having Nylon fibers was performed using water absorption,
permeability, carbonation resistance, and acid attack resistant. Mechanical tests (compressive and tensile) were conducted
for modified as well as control mix. Test results indicate that the passing and filling ability decreased while segregation
and bleeding resistance increased with NFs. Furthermore, test results showed a significant increase in strength up to
1.5% addition of nylon fibers and then strength decreases gradually. Durability parameters were significantly improved
with the incorporation of NFs relative to the control mix. Overall, this study demonstrated the potential of using nylon
fibers in self-compacting concrete with improved durability and mechanical properties.SIThe author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding this work through group research program under grant number RGP. 1/100/42 and Taif University Researchers Supporting Project (number TURSP- 2020/276), Taif University, Taif, Saudi Arabi
Antiplasmodium and chloroquine resistance reversing effects of embelin against Plasmodium falciparum K1
Background: Emergence of chloroquine (CQ) resistance among different strains of Plasmodium falciparum is the worst catastrophe that has ever perplexed efforts to eradicate malaria. This behooved the scientists to search for new alternatives or sensitizers that augment its action. Method: In this experiment, the potential of embeline, a quinonoid phytochemical obtained from the Indian plant Embelia ribes, to inhibit the growth and sensitize CQ action was screened using SYBRE green-1 based drug sensitivity assay and isobologram technique respectively. Its effect on both RBCs and Vero cells stability and RBCs fragility was screened to assess its safety. To depict its molecular mechanism, its effect on hemozoin formation and the new permeation pathway (NPP) of the host RBCs membrane were screened. Furthermore, its anti-oxidant activity was measured using the conventional in vitro tests and its molecular characters were obtained using Molispiration program. Results: The results showed that its antiplasmodial effect was weaker than CQ but synergism was obtained when they were combined together. Its low anti-plasmodial potency and poor selectivity toward RBCs reduces its eligibility to be introduced as an antimalarial. Nevertheless, it synergized CQ at a concentration within the safe limit. Embelin did not produce any impact on NPP but its impact on hemozoin formation was pronounced. Its antiplasmodium effect can be attributed to the latter or to its effect on RBCs membrane but further investigations are required to detect its CQ resistance. Conclusion: Overall, embelin is not ideal to be used as antiplasmodium but can be suggested as CQ resistance reversing agent
The Present State of the Use of Waste Wood Ash as an Eco-Efficient Construction Material: A Review
[EN] A main global challenge is finding an alternative material for cement, which is a major source of pollution to the environment because it emits greenhouse gases. Investigators play a significant role in global waste disposal by developing appropriate methods for its effective utilization. Geopolymers are one of the best options for reusing all industrial wastes containing aluminosilicate and the best alternative materials for concrete applications. Waste wood ash (WWA) is used with other waste materials in geopolymer production and is found in pulp and paper, wood-burning industrial facilities, and wood-fired plants. On the other hand, the WWA manufacturing industry necessitates the acquisition of large tracts of land in rural areas, while some industries use incinerators to burn wood waste, which contributes to air pollution, a significant environmental problem. This review paper offers a comprehensive review of the current utilization of WWA with the partial replacement with other mineral materials, such as fly ash, as a base for geopolymer concrete and mortar production. A review of the usage of waste wood ash in the construction sector is offered, and development tendencies are assessed about mechanical, durability, and microstructural characteristics. The impacts of waste wood ash as a pozzolanic base for eco-concreting usages are summarized. According to the findings, incorporating WWA into concrete is useful to sustainable progress and waste reduction as the WWA mostly behaves as a filler in filling action and moderate amounts of WWA offer a fairly higher compressive strength to concrete. A detail study on the source of WWA on concrete mineralogy and properties must be performed to fill the potential research gap.S
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