Best Conditions Of Use Research Articles

Case study: structural feasibility analysis for a reinforced concrete building

Currently, the residential building sector in Brazil is experiencing continuous growth, despite the adverse impacts caused by 2 years of the Covid-19 pandemic. Therefore, there is a demand for structural projects that enable the execution of these works from a structure that is viable from the point of view of safety, good conditions of use, comfort and economy. Technical and practical knowledge is a fundamental requirement for a good project, combined with skill in a technological analysis and sizing tool. Having said that, the present work proposed to develop the analysis and structural design, with the help of the Brazilian software TQS®, of a multi-family residential building in reinforced concrete, using both linear and nonlinear static analyses. The central motivation was to address structural challenges and ensure that the design complies with Brazilian standards, thereby improving the quality and safety of residential buildings. The work sought to follow all the design steps of a structure in order to meet the requirements recommended by Brazilian standards. Based on the analyses, it was possible to adopt solutions for the various structural problems that arose during the design and, finally, obtain the final document with all the details of the structure.

ANÁLISE DA UTILIZAÇÃO DA ESCÓRIA NO PROCESSO PRODUTIVO DO CIMENTO

The study carried out analyzed the chemical composition of blast furnace slag, highlighting calcium, silicon, aluminum and magnesium oxides as the main elements present, along with other elements in smaller quantities, such as FeO, MnO, TiO2 and sulfur. The application of slag in Portland cement was investigated based on data from references and bibliographic studies. The results and discussions indicated that the addition of slag in the manufacture of cement resulted in significant benefits, such as savings in grinding energy and a better distribution of clinker phases. Tests carried out on a raw mix containing 37% ground slag showed changes in the kinetics of clinker formation, highlighting the importance of the composition and proportion of slag used. Crystalline blast furnace slag was found to be more suitable than glassy slag for cement manufacture, due to its potential to improve operation and conserve energy. However, further studies and analysis are needed to fully assess the impact of slag on the durability and efficiency of cement, as well as to determine the best conditions of use. In summary, the study pointed out that the use of slag in the manufacture of cement brings relevant benefits,but highlighted the need for further research to confirm and expand the results obtained. The discussion emphasized the importance of considering the limitations of the study and discussing the implications of the findings for the field of study in question.

Anodal tDCS does not enhance the learning of the sequential finger-tapping task by motor imagery practice in healthy older adults.

Motor imagery practice (MIP) and anodal transcranial direct current stimulation (a-tDCS) are innovative methods with independent positive influence on motor sequence learning (MSL) in older adults. The present study investigated the effect of MIP combined with a-tDCS over the primary motor cortex (M1) on the learning of a finger tapping sequence of the non-dominant hand in healthy older adults. Thirty participants participated in this double-blind sham-controlled study. They performed three MIP sessions, one session per day over three consecutive days and a retention test 1 week after the last training session. During training / MIP, participants had to mentally rehearse an 8-element finger tapping sequence with their left hand, concomitantly to either real (a-tDCS group) or sham stimulation (sham-tDCS group). Before and after MIP, as well as during the retention test, participants had to physically perform the same sequence as fast and accurately as possible. Our main results showed that both groups (i) improved their performance during the first two training sessions, reflecting acquisition/on-line performance gains, (ii) stabilized their performance from one training day to another, reflecting off-line consolidation; as well as after 7 days without practice, reflecting retention, (iii) for all stages of MSL, there was no significant difference between the sham-tDCS and a-tDCS groups. This study highlights the usefulness of MIP in motor sequence learning for older adults. However, 1.5 mA a-tDCS did not enhance the beneficial effects of MIP, which adds to the inconsistency of results found in tDCS studies. Future work is needed to further explore the best conditions of use of tDCS to improve motor sequence learning with MIP.

Ophthalmic In Situ Gels with Balsam Poplar Buds Extract: Formulation, Rheological Characterization, and Quality Evaluation.

Balsam poplar buds are a raw material with a high content of polyphenols. Various polyphenols are known for their anti-inflammatory and antioxidant properties. In this study, an aqueous extract of balsam poplar buds was prepared in order to use environmentally friendly and non-aggressive solvents. The aqueous extract was lyophilized, and a 1% aqueous solution of lyophilized balsam poplar buds extract (L1) was prepared. L1 solution was used as a source of polyphenols for the production of ophthalmic in situ gels, so as to develop a product featuring antioxidant properties. Poloxamer 407 (P407) and hydroxypropyl methylcellulose (HPMC) were selected as gelling agents for the in situ gels. In order to select the formulations with the best conditions of use, formulations of different polymer concentrations (P407—10%, 12%, 15%; HPMC—0.5%, 0.75%) were prepared, choosing the same amount of the active polyphenol source L1. The physicochemical properties, rheological parameters, stability, and irritant effect on the rabbit corneal cell line (SIRC) were evaluated. Formulations in which P407 and HMPC concentrations were 10/0.75% and 12%/0.75% reached a gelation point close to the ocular surface temperature; the gels remained stable for 30 days and did not cause an irritant effect on the SIRC cell line.

Evaluation of the quality of wood from naturally fallen trees in the central Amazon

The objective of this study was to assess the quality and potential of wood from naturally fallen trees in the forest for product development and to provide subsidies for the use of raw material. The inventory of fallen trees was carried out along the road from the Experimental Station of Tropical Silviculture of the National Institute for Research in the Amazon (EEST / INPA) - Nucleus ZF-2, at km 23 of the ZF-2 road that starts to the left of km 50 of Highway BR-174 (Manaus-Boa Vista). Only trees that had fall characteristics due to natural factors, that is, that had exposed roots, were considered for the inventory. It was also stipulated as a requirement for measurement the diameter class of trees of 25 cm ≤ DBH ≤ 45 cm. From each naturally fallen tree, the diameters (largest and smallest) and their length were measured. 5cm thick discs were removed from the trees to obtain samples for scientific identification of the wood and determination of physical properties. Based on the inventory, it was identified that many of the trees naturally fallen in the forest are in good conditions of use, considering their woody material and their volume. The Alexa grandiflora species presented the highest volume with 2,788 m³ for a single tree, followed by the species Ormósia sp. with 2,287 m³ and Protium tenuifolium Engl with a volume of 1,269 m³. Regarding the health of the inventoried trees, all from the species Byrsonima crispaJuss. had no sign of degradation, followed by the species Croton lanjouwensis and Ingá sp. The most frequent class was medium density with 9 species with a variation of 0.47g/cm3 to 0.62g /cm3. Eperua schomburgkiana Benth was the most dense with 0.78g /cm3.The levels of degradation found and the intrinsic characteristics of the species did not compromise the possibilities of using this wooden product, and can represent an excellent opportunity for economic return, contributing to minimize the pressures exerted around the living forest.

Performance and thermal decomposition analysis of foaming agent NPL-10 for use in heavy oil recovery by steam injection

Abstract Foaming agents, despite holding potential in steam injection technology for heavy oil recovery, are still poorly investigated. In this work, we analyzed the performance of the foaming agent NPL-10 in terms of foam height and half-life under various conditions of temperature, pH, salinity, and oil content by orthogonal experiments. The best conditions of use for NPL-10 among those tested are T=220°C, pH 7, salinity 10000 mg·L–1 and oil content 10 g·L–1. Thermal decomposition of NPL-10 was also studied by thermogravimetric and differential thermal analyses. NPL-10 decomposes above 220°C, and decomposition is a two-step process. The kinetic triplet (activation energy, kinetic function and pre-exponential factor) and the corresponding rate law were calculated for each step. Steps 1 and 2 follow kinetics of different order (n = 2 and ½, respectively). These findings provide some criteria for the selection of foaming agents for oil recovery by steam injection.

A Bias and Variance Analysis for Multistep-Ahead Time Series Forecasting.

Multistep-ahead forecasts can either be produced recursively by iterating a one-step-ahead time series model or directly by estimating a separate model for each forecast horizon. In addition, there are other strategies; some of them combine aspects of both aforementioned concepts. In this paper, we present a comprehensive investigation into the bias and variance behavior of multistep-ahead forecasting strategies. We provide a detailed review of the different multistep-ahead strategies. Subsequently, we perform a theoretical study that derives the bias and variance for a number of forecasting strategies. Finally, we conduct a Monte Carlo experimental study that compares and evaluates the bias and variance performance of the different strategies. From the theoretical and the simulation studies, we analyze the effect of different factors, such as the forecast horizon and the time series length, on the bias and variance components, and on the different multistep-ahead strategies. Several lessons are learned, and recommendations are given concerning the advantages, disadvantages, and best conditions of use of each strategy.

Influence of the geomembrane on time-lapse ERT measurements for leachate injection monitoring

Leachate recirculation is a key process in the operation of municipal waste landfills as bioreactors. To quantify the water content and to evaluate the leachate injection system, in situ methods are required to obtain spatially distributed information, usually electrical resistivity tomography (ERT). However, this method can present false variations in the observations due to several parameters. This study investigates the impact of the geomembrane on ERT measurements. Indeed, the geomembrane tends to be ignored in the inversion process in most previously conducted studies. The presence of the geomembrane can change the boundary conditions of the inversion models, which have classically infinite boundary conditions. Using a numerical modelling approach, the authors demonstrate that a minimum distance is required between the electrode line and the geomembrane to satisfy the good conditions of use of the classical inversion tools. This distance is a function of the electrode line length (i.e. of the unit electrode spacing) used, the array type and the orientation of the electrode line. Moreover, this study shows that if this criterion on the minimum distance is not satisfied, it is possible to significantly improve the inversion process by introducing the complex geometry and the geomembrane location into the inversion tools. These results are finally validated on a field data set gathered on a small municipal solid waste landfill cell where this minimum distance criterion cannot be satisfied.

Efectividad del Mini-Mental en la detección del deterioro cognitivo en Atención Primaria

ObjectiveTo evaluate the diagnostic accuracy (DA) of the Mini-Mental State (MMS) for the detection of cognitive impairment (CI) in Primary Care (PC) and to determine the best conditions of use for that purpose. DesignPooled analysis of two prospective, double blind, studies on the evaluation of diagnostic tools with complete verification that were conducted in Madrid and Granada (Spain). SettingThe MMS was administered in PC and the final cognitive diagnosis (gold standard) was made in Specialized Care. ParticipantsSubjects with cognitive complaints or suspected of having CI were consecutively recruited in the PC clinic. Principal measuresThe DA of the MMS was evaluated using the area under the receiver operating characteristic (ROC) curve (AUC). The best cut-off point was selected according to the ratio of cases correctly classified (RCC) and to the kappa index. Direct (MMSd) and age- and education-adjusted (MMSa) total scores were analyzed separately. ResultsIn the total sample of 360 subjects (214 CI), the DA of the MMSd was significantly superior to that of the MMSa (0.84±0.02 vs 0.82±0.02, p≤.001). The yield obtained by the best cut-off point of the MMSd (22/23) was modest (RCC 0.77, kappa 0.52±0.05) and was not improved by any MMSa cut-off point. ConclusionThe DA of the MMS for detection of CI in PC was modest and did not improve with adjustment of the score by age and education. The best cut-off point was 22/23, inferior to the usually recommended cut-off.

Sunscreen products: What do they protect us from?

Whereas for fifty or so years acquiring a tan has been the trend for aesthetic reasons relating to current beauty criteria, the health authorities are now advocating vigilance in this area, prompted by the knowledge of the harmful effects of the sun, especially from its ultra-violet rays. In the European Union, sunscreen products are considered cosmetics and tests on their effectiveness can be performed in vivo or in vitro to determine four effectiveness indicators: the SPF (Sun Protection Factor), the PF-UVA (UVA Protection Factor), the SPF/PF-UVA ratio and the critical wave length. It is the erythemal SPF which is measured in the vast majority of cases: it can therefore be confirmed that sunscreen products protect us from sunburn under good conditions of use. We thought it would be interesting to calculate other indicators to assess protection against non-melanoma skin cancers (NMSC) and to quantify the effectiveness of the product against UVA1 or UVA2. To characterize the products tested, we have determined in vitro different SPF and PF-UVA values, by using not just the erythemal weighting factor but also the weighting factor relating to the non-melanocytic skin cancer (SPF cnm and PF-UVA cnm), by getting away from any weighting factor (SPF m and PF-UVA m) and lastly, by varying the integration limits to quantify the effectiveness of the tested product in the UVB (290–320 nm), UVA1 (340–400 nm) and UVA2 320–340 nm) fields. In this way, and using these new indicators, we have been able to qualify eleven commercial products—ten cosmetic products and one medical device. It can be interesting to take into account the non-melanocytic skin cancer protection in order to qualify the sunscreen products.

Synthetic sex pheromone of citrus leafminer in Brazilian citrus groves

The objective of this work was to determine the best conditions of use of the synthetic sex pheromone of Phyllocnistis citrella Stainton for monitoring this species in citrus groves in northeastern Brazil. Pheromone doses (0.0, 0.1, 1, 10 and 100 μg) and longevity (1, 15, 29, 43 and 57-day-old lures) and trap height (0.5, 1.5 and 2.5 m), color (green, red, and white) and model influence on P. citrella males capture were evaluated. The doses of 10 and 100 μg of the synthetic sex pheromone - a 3:1 blend of (Z,Z,E)-7,11,13-hexadecatrienal and (Z,Z)-7,11-hexadecadienal - attracted the greatest number of P. citrella males. Traps baited with these two both dosages continued to capture P. citrella males at a comparable rate for over eight weeks in citrus groves. Although there was no significant decrease in activity of both dosages until 57 days of exposure to the environment, the higher dose, as time passed, attracted significantly more P. citrella males than the lower dose. There were no significant differences in male capture in traps with synthetic sex pheromone placed at 1.5 and 2.5 m height, wich had the better results. Trap color and model did not affect male capture.

Efficacité de la lévofloxacine dans le traitement des exacerbations aiguës de bronchite chronique chez les patients avec facteurs de risque

Studies of acute exacerbations of chronic bronchitis (EXCB) included in the approval documents of levofloxacin (LVF) were reviewed in light of the good conditions of use defined by the French marketing approval and the AFSSAPS recommendations. The approval documents included two American studies comparing LVF 500 mg/d for 5-7 days with cefaclor 750 mg/d for 7-10 days or cefuroxime axetil (CXM) 500 mg/d for 7-10 days. A new descriptive analysis of efficacy was performed on a population meeting the recommendation criteria for antibiotic treatment in patients with clinical signs of obstruction. This analysis was stratified by number of risk factors (RF) for the following aggravating conditions: age above 65 years, diabetes or corticosteroid therapy. In the American studies, clinical efficacy, measured by rate of success in the total population, in the EXCB population requiring antibiotic therapy with or without risk factors, and in the EXCB population with at least one and at least two of the above-cited risk factors was 93.4% (351/376), 93.0% (268/288), 90.4% (122/135) and 94.4% (34/36) respectively with LVF and 92.2% (354/384), 92.5% (273/295), 87.7% (128/146) and 79.3% (23/29) respectively with the compared drugs. In the European study, the clinical efficacy in the total population, in the EXCB population requiring antibiotic therapy with or without risk factors, and in the EXCB population with at least one and at least two of the above-cited risk factors was 81.9% (195/238), 82.4% (182/221), 78.9% (112/142) and 75.0% (27/36) respectively with LVF and 72.5% (166/229), 74.0% (154/208), 73.1% (95/130) and 58.3% (21/36) respectively with the compared drugs. The efficacy of levofloxacin is thus confirmed for EXCB with signs of obstruction. When stratifying for RF, the efficacy of LVG persists with increasing numbers of RF, a result not observed with the compared drugs.

Improvement of the sensitivity of the scalar indicators (crest factor, kurtosis) using a de-noising method by spectral subtraction: application to the detection of defects in ball bearings

The aim of this article is to show the interest of spectral subtraction for the improvement of the sensitivity of scalar indicators (crest factor, kurtosis) within the application of conditional maintenance by vibratory analysis on ball bearings. The case of a bearing in good conditions of use is considered; the distribution of amplitudes in the signal is of Gaussian kind. When the bearing is damaged, the appearance of spallings comes to disturb this signal, thus modifying this distribution. This modification is due to the presence of periodical impulses produced each time a rolling element meets a discontinuity on its way. Nevertheless, the presence of background noise induced by random impulse excitations can have an influence on the values of these temporal indicators. The de-noising of these signals by spectral subtraction in different frequency bands allows to improve the sensitivity of these indicators and to increase the reliability of the diagnosis.

Advanced detection of rolling bearing spalling from de-noising vibratory signals

The aim of this article is to show the interest of spectral subtraction for the improvement of the sensitivity of scalar indicators (crest factor, kurtosis) within the application of conditional maintenance by vibratory analysis on ball bearings. The case of a bearing in good conditions of use is considered; the distribution of amplitudes in the signal is of Gaussian kind. When the bearing is damaged, the appearance of spallings comes to disturb this signal, modifying this distribution. This modification is due to the presence of periodical impulses produced each time a rolling element meets a discontinuity on its way. Nevertheless, the presence of background noise induced by random impulse excitations can have an influence on the values of these temporal indicators. The de-noising of these signals by spectral subtraction in different frequency bands allows to improve the sensitivity of these indicators and to increase the reliability of the diagnosis.

A photoelectrochemical cell for detecting pollutant-induced effects on the activity of immobilized cyanobacterium Synechococcus sp. PCC 7942

The cyanobacterium Synechococcus sp. PCC 7942 was immobilized by entrapment in poly(vinylalcohol) bearing styrylpyridinium groups (PVA-SbQ). Its properties in a single-compartment photoelectrochemical cell using platinum electrodes in potentiostatic mode were compared with the native material. The operational activity was measured in the presence of an electrolytic solution containing 20 mM sodium phosphate, 0.15 mM NaCI, and 1 mM MgCI 2. The best conditions of use are pH 6.5, 35°C and a 2,5-dichlorobenzoquinone concentration equal to 0.4 mM with native cyanobacteria or 0.5 mM after entrapment. The storage stability of immobilized cyanobacteria maintained in a dry state was good. The membrane made with PVA-SbQ 3500 kept 90% activity after 60-day storage at −18°C in the dark and 75% activity after the same time at +5°C in the dark. Using this procedure, the photocurrent could be inhibited by pollutants such as diuron and mercuric chloride. After entrapment the detection limits (corresponding to a 10% inhibition) were respectively 0.2 μM and 0.06 mM for diuron and mercuric chloride. The potential of this photoelectrochemical cell with cyanobacteria immobilized in PVA-SbQ for use as a bioassay for phytotoxicity measurements is discussed.

Potential for use of a cyanobacterium Synechocystis sp. immobilized in poly(vinylalcohol): Application to the detection of pollutants

A cyanobacterium, Synechocystis sp. PCC 6803, was immobilized by entrapment in poly(vinylalcohol) bearing styrylpyridinium groups. Its properties in a single-compartment micro-photoelectrochemical cell using platinum electrodes in potentiosatic mode were compared with the native material. The operational activity was measured in the presence of an electrolytic solution containing 20 mM sodium phosphate, 0.15 mM NaCl and 1 mM MgCl2. The best conditions of use are pH 7.0, 38 C and a 2,5-dichlorobenzoquinone concentration equal to 350 M with native cyanobacteria or pH 6.5, 25C and 500M 2,5-dichlorobenzoquinone after entrapment. Using this procedure, the photocurrent could be inhibited by pollutants such as Diuron or HgCl2. After entrapment, the detection limits (corresponding to a 10% inhibition) were respectively 0.5 M and 50M for Diuron and HgCl2 after five minutes of incubation. A permeabilization technique was used to increase sensitivity of the procedure to the detection of HgCl2 (25% inhibition with 50M after five minutes of incubation).

Acetylcholine biosensor involving entrapment of two enzymes. Optimization of operational and storage conditions

A bi-enzymatic sensor for the determination of acetylcholine was prepared by co-entrapment of acetyl-cholinesterase and choline oxidase in poly(vinyl alcohol) bearing styrylpyridinium groups. The measurements were based on the detection of enzymatically liberated hydrogen peroxide. The best conditions of use are pH 8, 30°C and a buffer concentration higher than 0.05 M. The storage stability in a dry state is excellent.

Solar energy storage by natural zeolites. V. optimization of the thermal activation process of chabazite TUFF

A research has been carried out, aiming to optimize the thermal activation of chabazite tuff. The thermogravimetric examination of the dehydration process has been carried out, as a function of several parameters, including tuff grain size (6–250 mesh), activation temperature (100–375 °C), heating rate (1–100 ° C min ), obtaining indications on the best conditions of use. The ability of chabazite tuff to store thermal energy has been confirmed, pointing out that effective activations in static conditions are possible in few (1–4) hours at temperatures no higher than 200 °C.

Thermodynamic study of the formation of adenine nucleotide · manganese complexes: I. “pH Stat” titration method results

The thermodynamics associated with the Mn 2− · ATP, Mn · ADP − and Mn · AMP complex formation reactions determined from K potentiometric measurements at I = 0.2 are reported for the temperature range 1–45°C. The K values increase with the lenght of the phosphate chain and with temperature. The limits and the best conditions for use of the “pH stat” titration method are discussed. Comparison with the results obtained by potentiometric and calorimetric methods in the case of Mg · nucleotide complexes is made.

The control of weeds in turf

AbstractIn Great Britain the turf grass crop accounts for about one million acres and is of considerable value. Much of it requires to be in good order throughout the year but surface quality, as distinct from grass quality, varies with the sport or game for which the turf is to be used.Of all the problems associated with turf management, weed control is pre‐eminent, since certain weeds are universal where grass is cut short. Short mowing determines the weed species that are able to persist, and by reducing ground‐floor competition permits their increase. By good management a weed‐free sward can be kept in this state for a long period, but the production of a weed‐free turf is a problem facing most turf users. Methods of control involve mechanical operations, such as raking, and the use of chemicals, varying from the sulphates of ammonia and iron to the plant poisons and then to the growth‐regulating substances or‘hormone’weedkillers. Methods of using all these are described, with data on the effects of repeated applications of the selective weedkillers for resistant weeds. The best conditions for use are also described.Reference is made to 2,4,5‐T (2 : 4 : 5‐trichlorophenoxyacetic acid) for weed control in turf and also to growth‐stunting chemicals such as maleic hydrazide. There is a possibility of controlling growth of long grass (on verges or in cemeteries, for example), but for fine turf there seems to be little likelihood of future application of such materials.