Workable Level Research Articles

Sustainable design and ecological evaluation of low binder self-compacting concrete

Self-compacting concrete (SCC) is a kind of high-performance concrete that is able to consolidate under its own weight without vibration. Due to its high binder content, the production of SCC normally needs a larger number of cement, the production of cement are associated with high energy consumption and CO2 emissions, which result in serious environmental pollution. To maintain the ecological sustainability of SCC, this research recommends a sustainable mix design method for SCC with a low binder content based on particle packing theory. The packing density of the concrete mixture is optimized by selecting an appropriate powder composition and particle gradation of the aggregate. Using the SCC mix design with the optimal packing density, a sustainable SCC can be achieved with the lowest possible of binder content while maintaining the desired level of workability and mechanical performance. The proposed design reduces the required binder content in the SCC mixture by 16%, the energy consumption during production of concrete by 30.57%, the CO2 emissions by 33.98%, and the material cost by 6.24%, respectively, compared with the typical mix design recommended by the American Concrete Institute (ACI C237) standard for similar 28-day compressive strength. The proposed mix design strikes a good balance between the ecological sustainability and performance based behaviors of SCC.

Production of eco-efficient earth-based plasters: Influence of composition on physical performance and bio-susceptibility

An experimental campaign was developed to evaluate the properties of earth plastering mortars, not only at the level of workability and physic-mechanical performance but also their susceptibility for biological colonization. A ready-mixed earth mortar and several other mortars formulated with a raw clayish earth were produced. The influence of partial replacement of fine sand by a phase change material (PCM) and the addition of low amounts of oat fibres and hydrated air lime were assessed. The experimental campaign shows that the PCM completely changes the mortar workability, with a decrease on wet density. The addition of PCM and fibres decreases the bulk density and, consequently, increases the porosity of the mortars. The presence of PCM, fibres and air lime decreases the thermal conductivity. Earth mortars are susceptible to mould development, and the fibres or PCM seem to intensify their bio-susceptibility. A low addition of air lime increases pH and inhibits fungal growth though decreasing the mechanical properties. Mortars with PCM, fibres and air lime present a higher surface roughness in comparison to other mortars, including the ready-mixed earth mortar with fibres. Surface roughness was found to be an important factor influencing the level of colonization.

The impact of internet-based cognitive behavior therapy on work ability in patients with depression - a randomized controlled study.

ObjectivesThe aim of this randomized controlled trial (RCT) was to investigate the effects of internet-based cognitive behavior therapy (ICBT) treatment for depression compared to treatment-as-usual (TAU) on improving work ability and quality of life in patients with mild-to-moderate depression. We also examined whether patients treated with ICBT returned to work more rapidly, that is, had fewer days of sick leave, than patients treated with TAU.DesignThis study is based on material from the PRIM-NET RCT that took place between 2010 and 2013.SettingPrimary care centers in Region Vastra Gotaland, Sweden, population about 1.6 million.PatientsA total of 77 patients with depression randomized to either ICBT (46 patients) or TAU (31 patients). Mean age of participants was 35.8 years, and 67.5% were women.Main outcome measuresWork ability was measured with the Work Ability Index, depressive symptoms with Montgomery Asberg Depression Rating Scale – self-rating version (MADRS-S), quality of life with EuroQoL-5D (EQ-5D), and number of sick leave days.ResultsBoth groups showed an association between improved work ability and reduction of depressive symptoms and between improved work ability and better quality of life. ICBT could not be shown to improve work ability more than TAU among patients with mild-to-moderate depression. There were no differences between the groups concerning number of patients with sick leave or number of sick leave days.ConclusionOur study indicates that a high level of work ability has an association with high health-related quality of life in patients with mild-to-moderate depression, whether they are treated with ICBT or TAU. ICBT has previously been found to be cost-effective and can be seen as a good alternative to TAU. In addition to the ICBT, an intervention oriented toward the work place might improve work ability and reduce the number of sick leave days among patients with depression.

The use of shear responsive stress control mastics as void fillers in medium voltage cable accessories

In the majority of polymeric medium voltage cables the outer conductive insulation screen (shield) is connected to earth (ground), and this contains the radial electrical field within the insulation. The status quo is disrupted when the screen is removed during jointing or terminating and the screen cutback is left untreated. The stress at the screen cut will be much higher than the design stress of the cable (Figure 1), and cable accessories are designed to control this stress to a workable level [1]. The example illustrated in Figures 1 and 2 shows this effect with a nongeometric stress control method, but similar effects will occur with geometric systems. Use of an effective stress control system ensures that the stress lines are redistributed to reduce the highly localized stress at the screen cut.

Data Storage and Retrieval on Nanoparticles

Recent advances at developing nanoscale electronic devices lead us to believe that in the near term the nanomemories in the form of nanodisks and nanotubes will replace existing storage systems and will be integrated into the implementation of nanocomputers and complex nanosensor systems. In this work the issue of recording and reading data using the magnetic vortex of nanodisks is addressed. By using the polarity and chirality properties of the magnetic vortex it may be possible to store information in binary or nonbinary form. Nevertheless, as in any storage system, information can be altered by the presence of noise, and therefore it is necessary to incorporate error control coding. In this regard, here we analyse the behaviour of the proposed system using Turbo coding and Low Density Parity Check (LDPC) coding in order to correct errors in the writing and reading process in nanoparticles. Simulations were performed for the binary case considering the polarity of the magnetic vortex to store information. This, because it appears to be the first workable level in the short term, before reaching practical implementations involving the simultaneous control of polarity and chirality to store non-binary data.

Mitigation of the negative effects of recycled aggregate water absorption in concrete technology

The widespread use of natural aggregates in construction activities, together with the global population increase, gave rise to a depletion of this natural resource and to progressive increase of its transport distances. On the other hand, the construction and demolition wastes (C&DW) resulting from the construction activities are often deposited in landfills and city outskirts, causing environmental and social problems, such as erosion, deforestation, water contamination and human conflicts. The reuse of C&DW in concrete preparation would be a good solution for both problems. Recycled aggregates show, however, high water absorption due to porosity. At saturation, water flows from the inside to the engaging cement paste matrix and at dryness the opposite process occurs. This water flow breaks the aggregate-cement paste bonds and increases the W/C ratio in the interfacial transition zone, this degrades the fresh and hardened concrete properties.In this work a staged mixing method based on the aggregate water absorption over time was developed. A staged mixing procedure was optimized to regulate the water flow and manufacture concrete, using recycled aggregates, with levels of workability, strength and shrinkage equivalent to those of conventional concrete. The physical, mechanical and geometrical properties of the aggregates were related to the properties of concrete in its fresh and hardened state. Three types of commercial recycled aggregates were evaluated. Two types of natural aggregates were also studied for comparison purposes.

Mechanochemical synthesis of one-part alkali aluminosilicate hydraulic cement

A novel approach was devised to synthesize a sustainable hydraulic cement based on alkali aluminosilicate chemistry via mechanochemical activation. This approach builds upon past work on activation of aluminosilicate precursors using alkaline solutions to produce inorganic binders for concrete construction. Recent efforts to develop one-part hydraulic cements based on the chemistry of alkali-activated aluminosilicates have resorted to high-temperature processing techniques which compromise the sustainability advantages of the system, and also require curing at elevated temperatures. The mechanochemical process developed here takes place at room temperature, and yields a hydraulic cement that does not require addition of caustic solutions to render binding effects via room-temperature curing. Processing of this hydraulic cement takes place at room temperature; this advantage together with extensive use of recycled raw materials yield significant sustainability benefits. The (dry) raw materials used for mechanochemical processing of hydraulic cement included coal fly ash, quick lime, sodium hydroxide and Magnesium oxide. The mechanochemically processed hydraulic cement was evaluated through performance of tests concerned with their pH, heat of hydration, chemical composition, crystallinity and microstructure. The hydraulic cement was used to produce concrete materials cured at room temperature. The resulting concrete materials were found to provide desired levels of workability in fresh state and compressive strength after curing, which were comparable to those of Portland cement concrete. Investigations were also conducted on the hydration kinetics of the hydraulic cement and the microstructure of its hydrates in order to gain insight into its hydration process and the nature of hydration products.

On program of extracurricular mini-football training program for university girl students

The research is aimed at working out of efficient program for first year girl students’ health improvement, which is based on mini-football means’ application in extra-curricular activities. Purpose: to substantiate the program of one year mini-football trainings for girl students. Material: one year experiment envisaged participation of 18-20 years’ age 56 first year girl students (two groups, 28 people each). The girl students of every group endured different physical loads: group 1 - 70% of specific means and 30% of non-specific; group 2 - 65% of specific means and 35% of non specific. Results: we worked one year efficient program for girl students’ health improvement, which was based on application of mini-football specific and non specific means’ optimal correlation in extracurricular trainings. We found that optimal correlation of specific and non-specific training loads was 70:30 (%). Practically equal level of workability in both groups was ensured by the following: in group 1 - at the account of special endurance; in group 2 - by means of general physical training. Conclusions: we recommend the program of one-year mini-football trainings, which ensures improvement of physical and technical fitness, rising of girl students organism’s and health indicators.

An effort to assess the relation between productivity loss costs and presenteeism at work

Purpose. This study assesses potential presenteeism costs and the association of these with a company’s business figures. Materials and methods. We conducted the questionnaire surveys in alternate years between 2003 and 2007 and linked them to sickness absence register data. Perceived work ability levels were assessed and converted into presenteeism days using the Presenteeism Scale tool. Sickness absence and presenteeism days were converted into monetary figures using median monthly salary information. Results. The share of presenteeism costs was constant at about 1% of annual turnover and about 3.7% of personnel costs. The lowest annual presenteeism cost per employee was EUR 986 and the highest was EUR 1302. The lowest number of presenteeism days per employee in a year was 8.7 days and the highest number was 10.4 days. Estimated losses to a company due to sickness absences and presenteeism ranged from EUR 4.6 million to EUR 5.6 million annually. The potential presenteeism costs to the company and to Finnish society were vast. Conclusions. Presenteeism is a costly problem but more research is needed to reveal the connections between presenteeism and a company’s turnover, personnel costs and profit.

Physicians' occupational stress, depressive symptoms and work ability in relation to their working environment: a cross-sectional study of differences among medical residents with various specialties working in German hospitals

ObjectivesThis study aimed to analyse and compare differences in occupational stress, depressive symptoms, work ability and working environment among residents working in various medical specialties.Methods435 German hospital residents in medical...

Investigation on modulus of elasticity of powder-activated geopolymer concrete

Geopolymer is an inorganic binder, synthesised by the activation of aluminosilicate compounds by strong alkali solution. Previous researches suggested that geopolymer concrete possessed superior mechanical properties over ordinary Portland cement (OPC) concrete; however, modulus of elasticity was found lower than OPC concrete of same grade. Two types of powder-activated geopolymer binders were used to produced geopolymer concretes of four different grades and two workability levels; normal and super-workable. Development of compressive strength and modulus of elasticity geopolymer concretes were investigated at ambient curing and compared with OPC concrete of same grade. Early age compressive strength of geopolymer concrete was lower than OPC concrete of same grade; however, the ultimate strength was significantly higher. The modulus of elasticity of geopolymer normal-workable concrete was similar to OPC concrete of same grade and complied with AS-3600. However, modulus of elasticity of geopolymer super-workable concrete was significantly lower than normal-workable concrete of same grade.

Investigation on compressive strength development and drying shrinkage of ambient cured powder-activated geopolymer concretes

Geopolymer is an inorganic polymer binding material, generally formed by the reaction between aluminosilicate materials and alkali activator solution. Previous researches on geopolymer concrete around the world suggested that geopolymer concrete possess superior mechanical and durability properties over ordinary Portland cement (OPC) concrete, such as higher indirect tensile strength and resistance to sulphate attack. Generally, fly ash-based geopolymer concrete was cured in elevated temperature for higher early age strength because of their longer setting time in ambient temperature. Published engineering properties of geopolymer concrete cured at ambient temperature are not abundant. In this research, two types of powder-activated geopolymer binders were used as binding material. A detailed study of compressive strength and drying shrinkage of different grades (40, 50, 65 and 80 MPa) of geopolymer and OPC concrete with different workability levels (normal-workable and super-workable) were carried out. All the concrete specimens were cured at standard laboratory temperature. The compressive strength development of geopolymer concrete in early age was relatively lower than OPC concrete; however, the later age strength was significantly higher. The drying shrinkage of geopolymer concrete was similar to OPC concrete of same grade and complied with Australian Standard 1379; however, it was higher than estimated values from Australian Standard 3600. The drying shrinkage results of this study were higher than drying shrinkage of accelerated cured geopolymer concretes in previous investigations. Super workable concrete exhibited higher drying shrinkage than normal workable concrete of same grade.

Effects of Work-Related Stress on Work Ability Index among Iranian Workers.

BackgroundWork Ability Index (WAI) is a well-known and valid self-report tool that has been widely used in various studies to identify and avoid early retirement and work-related disability. Nevertheless, very few studies have been carried out to evaluate work ability in Iran. We aimed to investigate the WAI and the effect of work-related stress on it among Iranian workers.MethodsA cross-sectional, descriptive and analytic study was carried out among 449 workers from five working sectors in three big cities of Iran. Work ability and work-related stress were measured using the Persian version of WAI and the Persian version of Health and Safety Executive Stress Indicator Tool.ResultsMore than a third of the workers surveyed (34.70%) did not have an appropriate level of work ability (WAI < 37). There was a significant correlation between subscales of work-related stress and the mean score of WAI. Furthermore, the variables of body mass index, sleep quality, exercise activity, job tenure, and three subscales of work-related stress including demands, supervisor support, and role were significant predictors of WAI.ConclusionAccording to the results of this study, the interventional programs must be focused on improving supervisors support, eliminating ambiguity and conflicts in the role of workers in their job and organization, reducing job demands, improving sleep quality, and increasing exercise activity.

Work ability, age and intention to leave aged care work.

To describe the work ability of mature age women workers in Australia's aged care sector, and to explore the relationship between ageing, work ability and intention to leave. Logistic regression techniques were applied to a sample of 2721 responses to a survey of mature age women workers in the aged care sector. Mature age women working in the Australian aged care sector have relatively high levels of work ability by international standards. Furthermore, their work ability remains high in their 50s and 60s, in contrast to some prevailing stereotypes. However, work ability is a key determinant of intention to leave in key occupational groups. Our findings challenge some prevailing stereotypes about the work ability of mature age workers. However, they lend support for the development of retention strategies, which incorporate programs that target low work ability.

PHYSICAL AND MECHANICAL PROPERTIES OF CONCRETE INCORPORATING INDUSTRIAL AND AGRICULTURAL TEXTILE WASTES

To reduce the impact on the environment, industrial and agricultural waste products such as carpet waste, sisal and flax have been added to the concrete. Usage of these materials in concrete does not only improve the strength of concrete but also leads to the proper disposal of these materials that leads to reduce the impact on environment. Fiber admixture can effectively improve the mechanical and physical properties of concrete. Utilization of recycled fibers from post-consumer, industrial waste and agricultural waste offer some benefits such as waste reduction, resource conservation, also low-cost materials and reduced need for land filling. Concrete is a tension weak building material, which is often cracked not ridden in plastic and hardened states, drying shrinkage and so on, low tensile strength limited ductility and resistance to cracking. In order to improve attempt has been made to study the effect of these materials on ordinary Portland cement concrete. In the experimental work, glass fibers, sisal, flax and waste carpet waste in different percentage (0.5%, 1% and 2 %) has been added by volume of concrete volume. The hardened concrete properties compressive strength, dry Shrinkage, Impact stress, The effect of temperature and Thermal conductivity of Concrete) were carried out. A total of Thirteen concrete mixtures were performed with cement content of 350 Kg/m 3 at water cement ratio = 0.525 , The amount of water was adjusted according to cement content, The super plasticizer dosage varied from 0.8% to 2.5% of cement content to achieve the required level of workability defined by a slump value of 10± 2cm.

Work Ability of Employees with Disabilities in Malaysia

Purpose: Based on a sample of employees with disability, this study aimed to: (1) evaluate the construct validity of work ability index (WAI), core self-evaluation scale (CSES) and job in general index (JIG), in order to make a valid and reliable assessment of their work ability, job satisfaction and core self-evaluation; (2) assess their levels of work ability, job satisfaction, and core self-evaluation; (3) investigate the associations of work ability with job satisfaction and core self-evaluation among them; and (4) determine which demographic characteristics significantly affect the work ability of employees with disability. Methods: The sample consisted of 275 employees with disability. Data was collected using a self-administered survey. The analysis focussed on: (1) CFA- for evidence of the construct validity of the employed scales; (2) Descriptive analysis - for evaluating the variables of the study; (3) Pearson correlation analysis – for understanding the simple correlation between variables of the study; and, (4) One-way ANOVA- for identifying the demographic factors that influence the work ability of employees with disability. Results: The findings indicated that 29.5% of the participants had poor levels of work ability, while 35.3% reported moderate levels of work ability. Also, 49.1% of the participants reported moderate levels of core self-evaluation, and 70.5% exhibited high job satisfaction. In this study, work ability was found to be associated with core self-evaluation and job satisfaction. Significant differences in work ability levels were found in terms of age, level ofeducation and employment status of the respondents. Conclusion: Work ability among employees with disabilities did not seem to be influenced merely by individual health status. Attitudinal and dispositional factors appeared to have a significant impact on their levels of work ability. The potential positive impact of education and employment status on employees’ levels of work ability are highlighted in this study.

Development of hospital nurses' work ability over a 2 year period.

A new approach to the study of work ability is an individually oriented approach. This approach increases our understanding of how work ability develops over time among individuals with a different level of work ability. To increase knowledge about individuals' work ability trajectories by studying hospital nurses' development of work ability over a 2 year period and factors associated with these trajectories. We used a data set of a prospective cohort study of hospital nurses, which was surveyed for 2 years by means of three questionnaires on work characteristics, health and work ability. The outcome variable was the general work ability trajectory over the course of 2 years (favourable/unfavourable). The predictors were the individual, physical and mental work ability and health characteristics at baseline. A multivariate backwards stepwise logistic regression analysis was used. Of 572 nurses in the cohort, nearly one-third (31%, 179/572) showed an unfavourable general work ability trajectory. Low physical work ability (odds ratio (OR) 1.82; 95% confidence interval (95% CI) 1.12-2.95) and high level of fatigue (OR 1.52; 95% CI 0.97-2.40) at baseline were predictors for the unfavourable course of self-reported general work ability. A substantial proportion of this cohort of hospital nurses experienced a reduction in work ability over the course of 2 years. Baseline physical work ability and level of fatigue were related to this. The next step is to address these factors when counselling nurses and evaluate the effect of interventions aimed at improving physical work ability and reducing fatigue.

High work ability and performance in psychiatric health care services: Associations with organizational, individual and contextual factors

IntroductionContinuing development in the German healthcare system has a strong influence on the work situation of hospital clinicians working in Psychiatric Medicine. Since the job demands for psychiatrists are growing, there is a strong need to promote, preserve and restore doctors’ work ability. The aim of this study was to assess the prevalence of psychiatrists’ work ability and to examine relations between work ability, job performance and organizational as wells as individual resources (e.g. work engagement) of doctors working in psychiatric hospitals. Methods and materialsThe current survey investigation was conducted as a cross-sectional. The Utrecht Work Engagement Scale, the Copenhagen Psychosocial Questionnaire and the Work Ability Index were used to evaluate psychiatrists’ work engagement, working conditions and work ability. ResultsPsychiatrists reported high levels of work ability and work engagement. Significant associations have been found between doctors’ sources of work engagement, work ability and organizational factors (e.g. possibilities for development, income, etc.). Moreover, significant differences in gender, age and marital status have been analyzed with regard to perceived work ability scores. ConclusionThe study results reflect the positive effect of supportive working conditions and work engagement on the preservation of psychiatrists’ work ability. Our research suggests that strengthening psychiatrists’ work ability and work engagement will contribute to a more sustainable workplace, in terms of both individual and hospital performance. Innovative strategies for physicians’ personal development and improving capacity and performance of clinicians working in Psychiatric Medicine are strongly required.

Ambiguity as Grasp: The Reworking of Sense

Ambiguity may lead us to insert abstractions into our experience that create a greater number of unanticipated, unintended consequences. When people move closer to the flux of ambiguity, they work to make sense of it. High reliability organizations react to ambiguity by increasing it momentarily. To increase ambiguity is to grasp more of the situation, to refrain from simplifications, and to strive for a workable level of ambiguity. This argument is developed through a focus on connotations of ambiguity, assumptions for organizing around ambiguity, and implications for practice. To grasp ambiguity is to adopt an attitude of wisdom.

Contribution of psychological, social, and mechanical work exposures to low work ability: a prospective study.

To determine the contribution of specific psychological, social, and mechanical work exposures to the self-reported low level of work ability. Employees from 48 organizations were surveyed over a 2-year period (n = 3779). Changes in 16 work exposures and 3 work ability measures-the work ability index score, perceived current, and future work ability-were tested with Spearman rank correlations. Binary logistic regressions were run to determine contribution of work exposures to low work ability. Role conflict, human resource primacy, and positive challenge were the most consistent predictors of low work ability across test designs. Role clarity and fair leadership were less consistent but prominent predictors. Mechanical exposures were not predictive. To protect employee work ability, work place interventions would benefit from focusing on reducing role conflicts and on promoting positive challenges and human resource primacy.