Decrease In Workability Research Articles

Impact of work-related musculoskeletal disorders on work ability among workers

To assess the impact of work-related musculoskeletal disorders (WRMDs) on work ability among workers. A total of 1686 workers in various occupations, such as administration and education, were enrolled as subjects using the random cluster sampling method. The WRMDs and work ability of all subjects were evaluated using standardized Nordic questionnaires for the analysis of musculoskeletal symptoms and the Work Ability Index (WAI) scale, respectively. Comparison of work ability and its classification between the disease group and the non-disease group was performed by paired t test, RxC table χ2 test, and the Wilcoxon rank-sum test. The relationship between work duration and work ability was analyzed by the Spearman correlation test and a multi-level model. (1). The work ability of workers in the disease group was significantly lower than that in the non-disease group (P<0.0 1). (2) There were significant differences in work ability between workers with different work durations (<10 years, 10-20 years, and ≥20 years) (F=22.124, P< 0.01). With the increase in work duration, the work ability of workers declined in both groups, and the work ability of workers in the disease group (Spearman coefficient rs=-0. 172, P<0.01) had a more significant decline than that in the non-disease group (Spearman coefficient rs=-0.104, P<0.01). WRMDs were important risk factors for the decrease in work ability among workers. (3) There were significant differences in constituent ratios and levels of work ability classification between the disease group and the non-disease group (χ2=121.097, P<0.01; Z=-10.699, P<0.01). The proportions of workers with poor and medium work ability in the disease group were significantly higher than those in the non-disease group, while the proportion of works with excellent work ability in the disease group was significantly lower than that in the non-disease group. The similar characteristics in constituent ratios and levels of work ability classification could be found between the disease group and the non- disease group in various occupations (P<0.01). WRMDs have a harmful effect on the work ability of workers, and the work ability of workers substantially declines with the increase in exposure time (work duration).

Use of OPC to improve setting and early strength properties of low calcium fly ash geopolymer concrete cured at room temperature

Most previous works on fly ash based geopolymer concrete focused on concretes subjected to heat curing. Development of geopolymer concrete that can set and harden at normal temperature will widen its application beyond precast concrete. This paper has focused on a study of fly ash based geopolymer concrete suitable for ambient curing condition. A small proportion of ordinary Portland cement (OPC) was added with low calcium fly ash to accelerate the curing of geopolymer concrete instead of using elevated heat. Samples were cured in room environment (about 23°C and RH 65±10%) until tested. Inclusion of OPC as little as 5% of total binder reduced the setting time to acceptable ranges and caused slight decrease of workability. The early-age compressive strength improved significantly with higher strength at the age of 28days. Geopolymer microstructure showed considerable portion of calcium-rich aluminosilicate gel resulting from the addition of OPC.

Effect of the surface treatment of recycled rubber on the mechanical strength of composite concrete/rubber

In this study, the influence of the addition of tire rubber in concrete was evaluated, to partially replace the fine aggregate of sand particles. The rubber fibers were also surface treated with different solvents to improve adhesion of the fibers to the concrete matrix. Compressive strength, slump test, Fourier Transform Infrared Spectroscopy of concrete samples were performed at time intervals of up to 28 days. The results showed a decrease on mechanical property values after the addition of tire rubber without treatment as well as a decrease of workability. It was also observed that the tire rubber treatment with acetone caused an increase of the mechanical strength of the samples.

The effect of prehydration on the engineering properties of CEM I Portland cement

Prehydration – the reaction between anhydrous cement and water vapour – has deleterious effects on engineering properties such as compressive strength, workability and setting time. This study assessed changes in the engineering properties of CEM I Portland cement exposed to relative humidities (RHs) of 60% or 85% for 7 and 28 days. Thin layers (no more than 2 mm thick) of CEM I 42.5R cement were exposed to controlled RHs of 60% and 85%, followed by assessment of compressive strength, setting time and workability. These measurements were complemented by characterising the prehydrated anhydrous cement using isothermal calorimetry, scanning electron microscopy, X-ray diffraction and thermal gravimetric analysis. Following prehydration at 60% RH, conventional hydration resulted in a negligible reduction in strength development plus a decrease in workability and increase in setting time. At 85% RH, compressive strength was greatly reduced, particularly at early ages. There was also a greater loss of workability and increase in setting time.

ERGONOMICS-JOB STRESS INTERVENSION (ERGO-JSI) REDUCES STRESS OF EMPLOYEES AT NATIONAL BANK IN DENPASAR

 Work stress may affect the quality of working life due to decrease of work ability, cognitive ability, and may also lead to risky behavior. The decrease in work stress could be reflected by the decrease in stressor, psychological distress and cortisol levels among employees. An ergonomic job stress intervention (Ergo-JSI) applied in this study has several advantages in regard to participatory ergonomics and individual orientation. The objective of this research is to analyze the decrease in job stress reflected by the decrease in stressor, psychological distress and cortisol levels among the employees of a National Bank in Denpasar, Bali, after the application of Ergo-JSI.This is an experimental study with treatment by subject design which was conducted from January to September 2011. Several dependent variables such as stressor and psychological distress were measured using the Indonesian version of Brief Job Stress Questionnaire (BJSQ), while the blood cortisol was measured using chemiluminescence technique. Totally 25 male employees of the Private National Bank in Denpasar 25 were used as the research subjects. They were randomly selected and their ages averaged 39.After the application of Ergo-JSI, a significant change (p &lt; 0.05), that is, a 6.8% decrease in stressor and a 23.7% fall in cortisol were found. Apart from that, a significant change (p&lt; 0.05), that is, a 28% decrease in psychological distress was also found.It could be concluded that the application of Ergo-JSI reduces job stress among the employees of the National Bank in Denpasar, Bali.

EFFECTS OF CIRCULATING FLUIDIZED BED COMBUSTION FLY ASH ON THE PROPERTIES OF ALKALI-ACTIVATED SLAG CEMENT MORTARS

This paper illustrates the result of a study on the influence of circulating fluidized bed combustion (CFBC) fly ash, sodium hydroxide (NaOH), sodium silicate (Na2SiO3), sodium phosphate (Na3PO4), and sodium carbonate (Na2CO3) as activators on the workability, bleeding, setting time, compressive strength, shrinking, and absorption of the alkali-activated slag (AAS) cement mortars. The addition of CFBC fly ash, Na3PO4, and Na2CO3 shows decrease of workability. But with Na2SiO3, the workability increase was observed. The setting time of Na3PO4, NaOH, Na2SiO3, and Na2CO3 activated slag cement mortars was found to be much faster than the setting time of slag cement mortars. Slag cement mortars activated with CFBC fly ash show similar strength properties to slag cement mortars. CFBC fly ash activated slag cement mortars gained higher early compressive strength and developed 50MPa compressive strength at the age of 56 days. CFBC fly ash activated slag cement mortars were found providing higher compressive strength than other activated slag cement mortars.

Adverse effects of effort–reward imbalance on work ability: longitudinal findings from the German Sociomedical Panel of Employees

The aim of this paper was to analyse the longitudinal effects of effort-reward imbalance (ERI) on work ability, mental health and physical functioning. A total of 603 men and women aged 30-59 years participating in the first two waves of the German Sociomedical Panel of Employees were included in the analyses. Work ability was assessed using the Work Ability Index. Mental health and physical functioning were assessed using scales of the Medical Outcomes Study 36-item Short-Form Health Survey. Our longitudinal analysis showed that high ERI-related work stress exposure at baseline was associated with a decrease in work ability, mental health and physical functioning over time. In case of work ability (b=-0.512; 95% CI -1.018 to -0.006) and mental health (b=-2.026; 95% CI -3.483 to -0.568), this also held true after adjusting for other factors of the work environment (physical demands, job control and psychological job demands). Work stress by ERI has an impact on work ability independent of and above that of other known explanatory variables.

Effect of Superplasticizer and NaOH Molarity on Workability, Compressive Strength and Microstructure Properties of Self-Compacting Geopolymer Concrete

The research investigates the effects of super plasticizer and molarity of sodium hydroxide alkaline solution on the workability, microstructure and compressive strength of self compacting geopolymer concrete (SCGC). SCGC is an improved way of concreting execution that does not require compaction and is made by complete elimination of ordinary Portland cement content. The parameters studied were superplasticizer (SP) dosage and molarity of NaOH solution. SCGC were synthesized from low calcium fly ash, activated by combinations of sodium hydroxide and sodium silicate solutions, and by incorporation of superplasticizer for self compactability. The workability properties such as filling ability, passing ability and resistance to segregation were assessed using slump flow, T-50, V-funnel, L-Box and J-ring test methods. It was found that the essential workability requirements for self compactability according to EFNARC were satisfied. Results showed that the workability and compressive strength improved with the increase in superplasticizer dosage. An increase in strength and a decrease in workability of these concrete samples were observed with the increase in molarity of NaOH solution from 8M to 14M. Improvement of interfacial transition zone (ITZ) and micro structure with the increase of SP and increase of concentration from 8M to 12M were also identified. Keywords—Compressive strength, Fly ash, Geopolymer concrete, Workability

An exploratory study of the Work Ability Index (WAI) and its components in a group of computer workers

The objective of this paper is to present a study on the assessment of the work ability of a group of aged computers workers. The study was developed with the goal of creating a decision making framework oriented towards the maintenance of the health and working ability of aged workers. Fifty computer workers participated in this study. They were administrative secretaries and computer technicians working mainly with office computers. The method used to assess the work ability was the Work Ability Index (WAI). 78% of the participants had good or excellent work ability and only 2% a poor one. The average WAI score was 40.5 (SD=5.761; min=27; max=49). This study confirms the decrease in work ability of workers while aging. The group overall work ability was slightly higher than the reference values develop by the Finnish Institute of Occupational Health. The assessment of work ability is fundamental to make age-friendly workplaces. WAI is one tool designed to perform such assessment. The results obtained could assist the early identification of situations where employees are struggling with their work ability, thus helping to prioritize ergonomic interventions devoted to improve the working conditions, and allowing the continued employment of aging workers on their current job.

High performance superplasticized silica fume mortars for ferrocement works

Ferrocement works demand cement mortars of good workability and high strength. Reduction in water-cement ratio combined with a refined pore structure increases the compressive strength in addition to the enhancement of durability characteristics, but the workability decreases. Workability becomes important, as the mortar has to easily penetrate between the layers of the mesh wires. A reasonably workable high strength cement mortar can be obtained by using a high cement content coupled with the use of superplasticizers. These were also found to retain the cohesiveness and check undesirable bleeding and segregation. An experimental program was conducted to study the functional efficacy of an SNF condensate used as a water reducing superplasticizer. The compressive strength and flow characteristics of the mortars were determined to decide their suitability for ferrocement works. The parameters included the mix proportions, the grade of cement, age of curing and the dosage of superplasticizer. It was concluded from the study that the addition of an optimum dosage of superplasticizer improved the workability and strength characteristics of silica fume mortars. There was a late gain in the compressive strength of silica fume mortars.

Women's narratives on experiences of work ability and functioning in fibromyalgia

Fibromyalgia is a significant health problem for women of working age. However, little is known about the long-term effects of fibromyalgia in everyday life or on work ability. A narrative interview study was conducted to explore the experiences of work ability and functioning of patients with a long history of fibromyalgia. Twenty women, aged 34-65 years, were purposively chosen for the interviews, to reach a wide range of patients with different social and professional backgrounds. Four types of experience concerning work ability were identified in the narratives: confusion, coping with fluctuating symptoms, being 'in between' and being over the edge of exhaustion. Severe pain and fatigue symptoms, combined with a demanding life situation and ageing, seemed to lead to substantial decrease in work ability and functioning over the long term. In the narratives, vocational rehabilitation or adjustments to work tasks were rarely seen or were started too late to be effective. Exploring the life stories of women with fibromyalgia can reveal the perceived causes and consequences of fibromyalgia related to work ability or disability, which can be utilized in developing client-centred rehabilitation approaches and effective interventions to support work ability and avoid premature retirement in fibromyalgia patients.

Influence of MB-value of manufactured sand on the shrinkage and cracking of high strength concrete

The relation between methylene blue (MB) value of MS and its limestone dust content and clay content was investigated. The effects of MB value ranging from 0.35 to 2.5 on the workability of fresh concrete and crack propagation characteristics at the age of 24 hours, and effects on the mechanical properties, dry shrinkage of the harden concrete were tested. The experimental results show that the MB value is not related with the limestone dust content of MS, but in direct proportion to clay content. With the increase of MB value, the concrete workability decreases, and the flexural strength and 7 d compressive strength reduce markedly, whearas the 28 d compressive strength is not affected. When the MB-value is less than or equal to 1.35, the change of the MB-value has a little influence on early plastic cracking and dry shrinkage property of concrete, but when the MB-value is more than 1.35, the tendency of plastic cracking and dry shrinkage is remarkable.

Rheology and hardened properties of single-coat render mortars with different types of water retaining agents

This paper compares the effect of two different water retaining agents in single-coat render mortars. The water retaining agent used in the experiments were cellulose methyl–hydroxypropyl and super absorbent polymers with various contents ranging from 0.05 to 0.15 wt.% of the total weight. Properties in fresh and hardened state were investigated. Fresh state properties include rheological behaviour, slump and density. Mechanical strength, transport properties through capillary absorption tests and water retaining capacity were measured in hardened state. Results indicate that MHPC promote the cohesion between the material particles in fresh state, increase the cohesiveness and is more efficient in fixing water molecules within their structure but, may lead to lower strength in the hardened state. SAP particles can also be used as water retaining admixtures, although they influence drastically the rheological parameters, specially the yield stress, traduced in removing water from the mixture, promoting a decrease on workability. However, the use of a plasticiser can help to circumvent this decrease of workability and, the higher flexural and compressive strength results of SAP mixtures indicate that SAP particles are more efficient to promote adequate water retention, even in adverse conditions.

Investigations on workability of commercial purity aluminum processed by equal channel angular pressing

Abstract Equal channel angular pressing (ECAP) is an important process for producing ultra fine grains in bulk metallic materials by means of severe plastic deformation. Workability of metals and alloys is an important parameter as it influences the fracture resistance of the material and the ease of subsequent forming by conventional techniques. In this study, the effect of various passes and processing routes of ECAP on the workability of commercially pure aluminum has been investigated. Aluminum specimens were subjected to ECAP using 90° angle ECAP die. ECAP was carried out using two processing routes for up to three passes. Microstructure characterization and mechanical property measurements were carried out. Workability was determined by means of upsetting tests on hexagonal collar specimens machined from specimens processed by ECAP. A Cockcroft fracture criterion was used to evaluate experimental results. It is observed that processing to two passes through Route C results in enhanced mechanical properties with only a slight decrease in workability.

Effects of type and dosage of alkaline activator and temperature on the properties of alkali-activated slag mixtures

In this paper the results of a study on the influence of sodium hydroxide, sodium carbonate, and sodium silicate, as activators, and temperatures in the range of 20–31 °C on the setting time and workability of the fresh alkali-activated slag cement (AAS) mixtures are presented. The results obtained show a significant acceleration of the setting of the AAS mixtures versus the setting of ordinary Portland cements. The highest acceleration of the setting was found with sodium silicate, while both sodium hydroxide and sodium carbonate show a moderate effect. The increase of temperature of the mixtures shows the acceleration of setting and decrease of workability. At the sodium silicate a continuous effect was observed as temperature was increased. But with sodium hydroxide and sodium carbonate a sudden acceleration of the setting, and workability decrease were observed, when the temperature reached the values 24–29 °C.

Work Ability of Health Care Shift Workers: What Matters?

This paper aims at identifying variables associated with inadequate work ability among nursing personnel at a public hospital, considering factors related to socio‐demographic, lifestyles, working conditions, and health outcomes. A cross‐sectional study was conducted in a university hospital in São Paulo, Brazil, as part of a larger research study on tolerance to 12 h night work. Nursing staff included registered nurses, nurse technicians, and nurse aides; in total, there were 996 healthcare workers (878 female; 118 male) at the time of the study. Some 696 workers (69.9%) of the population agreed to participate. Data collection (October 2004–July 2005) was based on a comprehensive questionnaire about living and working conditions (including incivility at work, work demands, work control, and support), mental and physical health symptoms (fatigue and sleep problems), and work ability. This report presents analyses of the adapted Brazilian version of the Work Ability Index (WAI) and associated variables. The study population worked one of the following shift schedules at this hospital: 12 h nights followed by 36 h off or 9 h or 6 h day (morning or afternoon) shifts. The mean age of the respondents was 34.9 (S.D.±10.4) years of age; 31.5% of the participants held two jobs. Statistical analyses using a hierarchical multiple logistic regression model were performed to evaluate the factors associated with inadequate (moderate and low scores) of the WAI. The significantly associated factors were socio‐demographic (income responsibility, sole breadwinner, raising kids, age group), working conditions (thermal discomfort, organization of the workplace, and verbal abuse), and health outcomes (high body mass index, obesity, sleep problems, and fatigue). In spite of limitations of the study design, results indicate that the nursing profession is associated with stressful working conditions, contributing to inadequate WAI. This is in addition to bad living conditions and precarious work. Intervention measures, either at the workplace or at individual levels, are necessary to prevent a decrease in work ability, even in this quite young working population.

Elderly workers in chemical, energetic, sanitary and public fields: Evaluation of work ability

The WAI (Work Ability Index) questionnaire, that evaluates the perceived work ability, has been given to a sample of 416 workers from chemical, energetic, sanitary and public fields. Results show a negative correlation between age and WAI score, that is a work ability decrease by aging. The total WAI score is lower in working fields where a more psycho-physical effort is requested. The sanitary field, in spite of a bigger psycho-physical effort, has a WAI score higher than other fields in the youngest age group, but it has the fastest decrease by aging. Aging influences negatively the self-perceived work ability related to following years, especially in those occupations with a bigger physical effort, according to the literature data. Moreover, the psychological evaluation is higher in those working fields and age groups with a higher WAI score. This data confirm that the good self-esteem and the psychological wellbeing can positively influence the work ability development. It is advisable to put in place primary and secondary prevention programs in order to decrease the main causes of morbidity and mortality, which would reduce work ability. Finally, it would be right, to introduce ergonomic measures in order to delay the work ability decrease by aging.

Influence of Modification of Annealing and Sheath Materials on Critical Current Density of Bi-2223/Ag Tapes

It is important to improve critical current density of silver-sheathed Bi-2223 tapes for practical applications of material. Bi-2223/Ag superconducting wires with various sheath materials were fabricated by stacking, drawing process with different pre-annealing schedules. Two kinds of powders were prepared. One was pre-annealed at 760/spl deg/C and low oxygen partial pressure, and the other was only calcined state. Before rolling process, round wires were pre-annealed at 760/spl deg/C and in a low oxygen partial pressure. Bi-2223/Ag conductor was needed softening annealing at low temperature during drawing process because pre-annealed precursor powder brought about decrease in workability. Pre-annealing let tetragonal structure of Bi-2212 phase of precursor transform to orthorhombic structure and reduce the fraction of second phases at superconducting wire, which could increase critical current density. However the breakages occurred at Ag-alloy sheathed long Bi-2223/Ag tapes during rolling after pre-annealing. Several pre-annealing scenarios were introduced to reduce the breakages during rolling process. We could achieve proper pre-annealing conditions for Ag-alloy clad Bi-2223 tapes by the analysis of mechanical properties. We could achieve highest Je of 8800 A/cm/sup 2/ at Bi-2223 tape by two-step pre-annealing.

Reuse of sewage sludge ashes (SSA) in cement mixtures: the effect of SSA on the workability of cement mortars

The influence of sewage sludge ash (SSA) on workability of cement mortars has been studied. The irregular morphology of SSA particles produced a decrease of mortar workability. A nonlinear reduction of workability in mortars containing SSA was observed, but when SSA content in mortars was increased the workability reduction was less significant. A superplasticizer is used in order to compensate the decrease of workability produced by SSA. When SSA sized fractions were used, only significant differences in workability for mortars prepared with high water volumes or with the presence of superplasticizer were observed.

Perceived work ability of home care workers in relation to individual and work-related factors in different age groups.

This study analysed the relationship between age and items of the Work Ability Index (WAI) among 19- to 62-year-old female home care workers (n = 636). The first significant decrease in work ability occurred between the ages of 40 and 44 years, and a second, sharper decrease occurred after 55 years of age. The subjects' physical work ability deteriorated as early as 35 years of age. In addition, current work ability, number of diagnosed diseases and work impairment due to diseases proved to be the most age-sensitive measures of work ability. The subjects who perceived their health status as poor had the highest risk for poor work ability. Moreover, the age-adjusted odds ratio indicated that the WAI was strongly associated with age and musculoskeletal and psychosomatic symptoms. Ergonomics, possibilities to control one's own work, time pressure and management were the features of work that predicted work ability. The study demonstrated the need to promote the work ability of home care workers early in working life. Among both older and younger workers, preventive measures should focus on the above-mentioned factors.