Artificial Intelligence Neural Network: Compressive Strength Prediction of Recycled Aggregate Concrete Samples

Old and demolished structures profusely exist in landfills because they are not being recycled frequently nor being employed correctly. This leads to an increase of construction and demolished wastes (C&D). These demolished structures and blocks can be broken down into smaller components to serve as aggregates (which are called recycled aggregates). Recycled aggregates are not being used regularly because they sometimes have detrimental influence on the compressive strength of concrete. Recycled concrete aggregate (RCA) reduces compressive strength of the concrete samples due to absorption issues related to the type, and age of the old concrete. Increase in water absorption levels leads to reduction in the compressive strength. If this issue is resolved, consumption of natural resources would decrease, and the use of recycled aggregate would increase which has beneficial reflection on the economy and the environment. The objective of this research was to develop a model to predict the compressive strength of concrete containing different percentages of RCA. This research studied the physical properties that reduce compressive strength, and even included the parameters that are aligned to the concrete mixture and treated them as input parameters in a prediction model. The model was created using artificial intelligence neural network. The built model included a specific prediction algorithm which was Bayesian Regularization Backpropagation which can deal with many types of data, even those of the random type. Although, the data was considered as non-linear, the Bayesian v probability algorithm was able to determine the pattern between the data and reduce the error by using the error function which was Mean Squared Error. The experimental data was collected from previous published research works in literature. The collection of the data and the evaluation of the model were both built upon specific criteria. The training results showed the success of the model. The model can be used as a tool by engineers to calculate compressive strength when recycled aggregates are added by entering the physical properties of the mixture. The work done here can be extended in the future to cover optimization of mechanical properties of concrete containing RCA

Analyzing the frequency shift of physiadsorbed CO2 in metal organic framework materials

Combining first-principles density functional theory simulations with IR and Raman experiments, we determine the frequency shift of vibrational modes of CO2 when physiadsorbed in the iso-structural metal organic framework materials Mg-MOF74 and Zn-MOF74. Surprisingly, we find that the resulting change in shift is rather different for these two systems and we elucidate possible reasons. We explicitly consider three factors responsible for the frequency shift through physiabsorption, namely (i) the change in the molecule length, (ii) the asymmetric distortion of the CO$_2$ molecule, and (iii) the direct influence of the metal center. The influence of each factor is evaluated separately through different geometry considerations, providing a fundamental understanding of the frequency shifts observed experimentally.Comment: 9 pages, 4 figure

Proposed Strategy for the Development of the Palestinian NGO sector

1. This strategy is intended for the broad range of non-governmental organizations in Palestine. The initiative to prepare this strategy came from the Project Management Office (PMO) of the Palestinian NGO (PNGO) Project of the World Bank in preparation for the third phase of PNGO. However, the strategy is not intended to be a strategy of the PMO for PNGO III only. It is crafted to address the alleged weaknesses of NGOs and the expectations of stakeholders of the role that they should play in responding both to current problems as well as long-term concerns. It is expected that implementation will be a collaborative undertaking by different stakeholders

Theoretical and experimental analysis of H2 binding in a prototype metal organic framework material

Hydrogen adsorption by the metal organic framework (MOF) structure Zn2(BDC)2(TED) is investigated using a combination of experimental and theoretical methods. By use of the nonempirical van der Waals density-functional (vdW-DF) approach, it is found that the locus of deepest H2 binding positions lies within two types of narrow channel. The energies of the most stable binding sites, as well as the number of such binding sites, are consistent with the values obtained from experimental adsorption isotherms and heat of adsorption data. Calculations of the shift of the H-H stretch frequency when adsorbed in the MOF give a value of approximately -30 cm-1 at the strongest binding point in each of the two channels. Ambient temperature infrared absorption spectroscopy measurements give a hydrogen peak centered at 4120 cm-1, implying a shift consistent with the theoretical calculations.Comment: 4 pages, 4 figure

Studiu și metode de acces în crearea accesului endodontic

Summary. The main objective of access cavity preparation is to identify the root canal entrances for subsequent preparation and obturation of the root canal system. Access cavity preparation can be one of the most challenging and frustrating aspects of endodontic treatment, but it is the key to successful treatment. Inadequate access cavity preparation may result in difficulty locating or negotiating the root canals. Good access cavity design and preparation is therefore imperative for quality endodontic treatment, prevention of iatrogenic problems, and prevention of endodontic failure.Rezumat. Obiectivul principal al prepararii cavităţii de acces este de a identifica intrările în canal, pentru pregătirea ulterioară și obturarea sistemului canalelor radiculare. Prepararea cavităţii de acces este una dintre cele mai dificile și mai frustrante aspecte ale tratamentului endodontic, dar este cheia succesului tratamentului. Prepararea inadecvată a cavităţii de acces poate duce la dificultăţi în localizăre acanalelor radiculare. Accesul reușit în cavitate, în cele din urmă, este imperativ pentru tratamentul endodontic de calitate, pentru prevenirea problemelor iratrogene și prevenirea eșecului endodontic

Pharmacokinetic and exposure-response analysis of pertuzumab in patients with HER2-positive metastatic gastric or gastroesophageal junction cancer

Purpose: To characterize the pharmacokinetics (PK) of pertuzumab and trastuzumab in patients with HER2-positive metastatic gastric or gastroesophageal junction cancer in the randomized, double-blind, phase III JACOB study (NCT01774786), and to evaluate the appropriateness of the pertuzumab regimen in these patients. Methods: Patients received 840 mg intravenous pertuzumab or placebo plus trastuzumab q3w and chemotherapy. Pertuzumab and trastuzumab were administered until disease progression or unacceptable toxicity. Chemotherapy was administered for up to six cycles or disease progression or unacceptable toxicity. Serum concentrations of pertuzumab and trastuzumab were measured. Pertuzumab PK was characterized across treatment cycles. The impact of anti-drug antibodies (ADAs) on pertuzumab PK and the impact of pertuzumab on trastuzumab PK were assessed. An exploratory exposure-efficacy analysis was also conducted. Results: In total, 374 patients in the pertuzumab arm had evaluable PK data. The mean observed pertuzumab steady-state serum trough (minimum) concentration (C) ± standard deviation was 114 ± 51.8 μg/mL. The target pertuzumab C of ≥ 20 μg/mL was reached in 99.3% of patients at Cycle 5 (steady state) and beyond. Greater than 90% of patients were above the PK target right after the first pertuzumab dose. There was no apparent impact of ADAs on pertuzumab PK nor of pertuzumab on trastuzumab PK. There were no differences in overall survival across Cycle 1 pertuzumab (C) or Cycle 5 pertuzumab (C) exposure quartiles. Conclusions: Pertuzumab exposure in JACOB was consistent with prior studies in advanced gastric cancer and breast cancer. The 840 mg q3w dose allowed the majority of patients in JACOB to achieve target pertuzumab concentrations and appears to be an appropriate dose selectio

A simple method for estimating relative risk using logistic regression

<p>Abstract</p> <p>Background</p> <p>Odds ratios (OR) significantly overestimate associations between risk factors and common outcomes. The estimation of relative risks (RR) or prevalence ratios (PR) has represented a statistical challenge in multivariate analysis and, furthermore, some researchers do not have access to the available methods. Objective: To propose and evaluate a new method for estimating RR and PR by logistic regression.</p> <p>Methods</p> <p>A provisional database was designed in which events were duplicated but identified as non-events. After, a logistic regression was performed and effect measures were calculated, which were considered RR estimations. This method was compared with binomial regression, Cox regression with robust variance and ordinary logistic regression in analyses with three outcomes of different frequencies.</p> <p>Results</p> <p>ORs estimated by ordinary logistic regression progressively overestimated RRs as the outcome frequency increased. RRs estimated by Cox regression and the method proposed in this article were similar to those estimated by binomial regression for every outcome. However, confidence intervals were wider with the proposed method.</p> <p>Conclusion</p> <p>This simple tool could be useful for calculating the effect of risk factors and the impact of health interventions in developing countries when other statistical strategies are not available.</p