Towards First-principles Electrochemistry

Chemisorbed molecules at a fuel cell electrode are a very sensitive probe of the surrounding electrochemical environment, and one that can be accurately monitored with different spectroscopic techniques. We develop a comprehensive electrochemical model to study molecular chemisorption at either constant charge or fixed applied voltage, and calculate from first principles the voltage dependence of vibrational frequencies -- the vibrational Stark effect -- for CO adsorbed on close-packed platinum electrodes. The predicted vibrational Stark slopes are found to be in very good agreement with experimental electrochemical spectroscopy data, thereby resolving previous controversies in the quantitative interpretation of in-situ experiments and elucidating the relation between canonical and grand-canonicaldescriptions of vibrational surface phenomena.Comment: 10 pages, 2 figure

Joint Density-Functional Theory of the Electrode-Electrolyte Interface: Application to Fixed Electrode Potentials, Interfacial Capacitances, and Potentials of Zero Charge

This work explores the use of joint density-functional theory, a new form of density-functional theory for the ab initio description of electronic systems in thermodynamic equilibrium with a liquid environment, to describe electrochemical systems. After reviewing the physics of the underlying fundamental electrochemical concepts, we identify the mapping between commonly measured electrochemical observables and microscopically computable quantities within an, in principle, exact theoretical framework. We then introduce a simple, computationally efficient approximate functional which we find to be quite successful in capturing a priori basic electrochemical phenomena, including the capacitive Stern and diffusive Gouy-Chapman regions in the electrochemical double layer, quantitative values for interfacial capacitance, and electrochemical potentials of zero charge for a series of metals. We explore surface charging with applied potential and are able to place our ab initio results directly on the scale associated with the Standard Hydrogen Electrode (SHE). Finally, we provide explicit details for implementation within standard density-functional theory software packages at negligible computational cost over standard calculations carried out within vacuum environments.Comment: 18 pages, 5 figures. Initially presented at APS March Meeting 2010. Accepted for publication in Physical Review B on Jul. 27, 201

Effect of GSM Radiation on White Blood Cells

The effect of continuous-wave radiation on peripheral blood in albino mice was investigated. A radiation frequency of 2450MHz was applied at an average power density of induced field 10mW/cm2. Ten 13 week old albino mice with average body mass of 35.0g were divided into 3 groups, preliminary group, control group, C and the irradiated group, E. Two (2) mice were used for preliminary studies, four (4) were kept to serve as control batch, and four (4) were exposed to microwaves for 60 days, at 2 hours per day. Peripheral blood samples were taken immediately after irradiation on the 1st, 16th, 32nd and the 60th day of the experiment. The total white blood cells count of both control, C batch and exposed, E batch, as well as the differential white blood cells count were investigated. The morphology of cells was also observed, during each session of the investigation in comparison with control C batch. The results revealed a decrease in the total white cell count which consistently continued in irradiated E batch from the 1st day of irradiation in the sample of the irradiated E batch in comparison with the control C batch samples. Slight increase in relative proportion of the neutrophil was observed in E batch sample in comparison with the C batch samples. Our investigation confirms wave exposure affects the white blood cells parameters of exposed animals

Spiritual well-being for croatian cancer patients: Validation and applicability of the croatian version of the eortc qlq-swb32

Spiritual well-being is a recognized predictor of health-related quality of life in palliative patients. No research in Croatia has yet addressed this field. This study, the first of its kind in Croatia, validated a Croatian translation of the EORTC QLQ-SWB32 measure of spiritual well-being with curative Croatian oncology patients and assessed its use and value. The study was conducted between July 2019 and January 2020 at the Department of Radiotherapy and Oncology, University Hospital Rijeka, with 143 cancer patients, using the linguistically validated Croatian version of the measure. All patients found the measure acceptable. Confirmatory factor analysis aligned with the structure found in previous studies. Cronbach’s alpha confirmed internal consistency. Female participants scored higher on the RSG (Relationship with Someone or Something Greater), RG (Relationship with God), and EX (Existential) scales, and on Global-SWB. Patients with breast and gynecological tumors scored higher on RG. Older patients scored lower on RSG, RG and EX. Retirees and those with below-average incomes scored lower on EX. Participants who identified as having no religion scored lower on RSG. Stage I cancer patients scored higher on RG. The Croatian version of the EORTC QLQ-SWB32 is an acceptable, valid, and reliable measure of SWB for Croatian cancer patients

Cluster Expansion by Transfer Learning from Empirical Potentials

Cluster expansions provide effective representations of the potential energy landscape of multicomponent crystalline solids. Notwithstanding major advances in cluster expansion implementations, it remains computationally demanding to construct these expansions for systems of low dimension or with a large number of components, such as clusters, interfaces, and multimetallic alloys. We address these challenges by employing transfer learning to accelerate the computationally demanding step of generating configurational data from first principles. The proposed approach exploits Bayesian inference to incorporate prior knowledge from physics-based or machine-learning empirical potentials, enabling one to identify the most informative configurations within a dataset. The efficacy of the method is tested on face-centered cubic Pt:Ni binaries, yielding a two- to three-fold reduction in the number of first-principles calculations, while ensuring robust convergence of the energies with low statistical fluctuations

Technology, Performance, and Market Report of Wind-Diesel Applications for Remote and Island Communities: Preprint

This paper describes the current status of wind-diesel technology and its applications, the current research activities, and the remaining system technical and commercial challenges. System architectures, dispatch strategies, and operating experience from a variety of wind-diesel systems will be discussed, as well as how recent development to explore distributed energy generation solutions for wind generation can benefit from the performance experience of operating systems. The paper also includes a detailed discussion of the performance of wind-diesel applications in Alaska, where 10 wind-diesel stations are operating and additional systems are currently being implemented. Additionally, because this application represents an international opportunity, a community of interest committed to sharing technical and operating developments is being formed. The authors hope to encourage this expansion while allowing communities and nations to investigate the wind-diesel option for reducing their dependence on diesel-driven energy sources

FACTS Devices as a Solution to Power Industries Problems: A Review

With an ever-increasing demand for power and establishment of new industries with high load demand, the need to for constant upgrade of powers system network is high. Such transmission networks are prone to external disturbances from loads, environment and other sources which leads to low power quality. Sudden application or removal of large loads. Large loads are known to draw more reactive power than the generated reactive power which lead to reactive power imbalance which can lead to total system collapse. In this paper, a critical review of how Flexible Alternating Current Transmission Systems (FACTS) devices are used to mitigate such issues to ensure power quality is done. Previous work on the integration of different FACTS devices were review to establish the advantage of FACTS devices over conventional solutions to power transmission problems.&nbsp

Non-perturbative embedding of local defects in crystalline materials

We present a new variational model for computing the electronic first-order density matrix of a crystalline material in presence of a local defect. A natural way to obtain variational discretizations of this model is to expand the difference Q between the density matrix of the defective crystal and the density matrix of the perfect crystal, in a basis of precomputed maximally localized Wannier functions of the reference perfect crystal. This approach can be used within any semi-empirical or Density Functional Theory framework.Comment: 13 pages, 4 figure

Hiv/Aids prevalence at the accident & emergency centre of a tertiary and referral health institution in Ghana

Background: Ghana has an estimated HIV prevalence of 1.4%, but the HIV prevalence of patients presenting at emergency departments in Ghana is not well documented in published literature. This study evaluated the prevalence of HIV infection at the Accident & Emergency Department, Komfo Anokye Teaching Hospital (KATH A&E), Kumasi, Ghana.Methods: A descriptive cross-sectional survey was carried out on patients aged 18 and above presenting to KATH A&E. An opt-in testing approach was used; consenting patients were screened for HIV using rapid HIV finger-stick testing with HIV 1-2 STAT-PAK. Sero-positivity was confirmed by OraQuick HIV 1-2 test. Data was analysed using multivariate logistic regression.Results: 1125 patients presenting at the KATH A&E during the study period were offered the Rapid HIV test. 667 of these patients consented to have the test. HIV prevalence was 13.5% (90/667). 53 females (58.9%) were HIV positive compared to 37 males (41.1%). The age group 30-50 years had the highest risk of being HIV-positive. Other socio-demographic variables such as educational level and occupation were significantly associated with HIV-infection (Pvalue = 0.001 at 95% CI).Conclusion: This study shows that emergency department HIV testing in Ghana is feasible. The prevalence of HIV sero-positive patients presenting at KATH A&E was tenfold higher than national estimates. We conclude that this study showed a high prevalence among patients seeking emergency care in our setting. Testing in the emergency department could lead to early detection of HIV-infected patients for linkage to care.Keywords: HIV Infections; HIV Screening; Prevalence, Diagnosis, Emergency Departmen