EFFECTS OF VARYING WATER-CEMENT RATIOS ON DIFFERENT GRADES OF CONCRETE USING LOCALLY MATERIALS

This research focused on laboratory tests that was conducted using locally available 10mm washed all-in gravel, quarry dust with varying water cement ratio. The research was carried-out using 108 (150 x 150 x 150) mm standard cubes that were all tested from three designed concrete mixes. In the present study, the role of water-cement ratio in compressive strength of concrete was investigated. The mixed concrete samples with water-cement ratios of 0.3, 0.35 and 0.40 were experimented for 3, 7, 21 and 28 days of curing. The results of compressive strength experiment showed that due to increase in water-cement ratio from 0.3 to 0.40, the compressive strength improved from 22 N/mm2 to 24.33 N/mm2 for 1:1.5:3 design mix, the compressive strength improved from 22.88 N/mm2 to 24 N/mm2 for 1:2:1 design mix, while compressive strength improved from 24 N/mm2 to 25.3 N/mm2 for 1:1:2 design mix   respectively. The results for compressive strength experiments showed that the 0.4 water-cement ratio resulted in the optimum compressive strength for all three design mixes.     &nbsp

Customer Acceptance of Self-Service Technology at Fast Service Restaurants in Tshwane

Objective: Technological advances have prompted many businesses to introduce self-service technology (SST) to improve customer waiting times and reduce operational costs. This study aims to determine the factors linked to the acceptance of self-service technology by customers at fast-service restaurants. Research Design & Methods: This research uses a quantitative method by surveying 172 customers who had visited self-service restaurants within the preceding six months. The Unified Theory of acceptance and use of technology (UTAUT) was used to determine the factors linked to the acceptance of self-service technology at quick-service restaurants. The Statistical Package for Social Sciences was used for analysis. Findings: It was found that age and gender moderate the relationship between the construct: performance expectancy ratio and SST usage intention, effort expectancy and SST usage intention, social influence and usage intention and lastly, age moderates the relationship between facilitating conditions and SST usage behaviour. Contribution & Value Added: The design of future self-service technology at restaurants should be constructed in a manner that would appeal to customers of all ages and gender. An education drive should be prioritised to educate customers about the benefits of self-service while ensuring that they also understand that technology does not reduce employment but may be used to create employment in other forms. Future studies should also investigate whether technology education might have a moderating effect on technology

Study of Mix Design for High Strength Concrete using Locally Occuring 10mm (3/8) All-in-one Aggregate Gravel

This paper presents a detailed study and mix analysis for high strength (HSC) and Normal Strength (NSC), the study monitored washed locally occurring 10 mm (3/8’) gravel aggregate as total replacement for coarse and fine aggregates .The aggregates were used in the combined state under natural condition. The study was carried out with mixes design containing aggregate with its combined and natural state incorporating fly ash and microsilica as supplementary cementitious materials. A total of 25 trial mixes was considered comprising 10 high strength and 15 normal strength concrete mixes. The variation of compressive strength of HSC and NSC was investigated as a function of fly ash/microsilica (FA/MS) and water/binder (W/B) ratios. One hundred and ninety six cube specimen of size 150mmx150mmx150mm were cast and tested for compressive strength after 3, 7 and 28 days wet curing.  The maximum 28-day of compressive strength of 88.9 MPa and 53.8 MPa was obtained for HSC and NSC respectively

Isotopic Dependence of the Casimir Force

We calculate the dependence of the Casimir force on the isotopic composition of the interacting objects. This dependence arises from the subtle influence of the nuclear masses on the electronic properties of the bodies. We discuss the relevance of these results to current experiments utilizing the iso-electronic effect to search at very short separations for new weak forces suggested by various unification theories.Comment: 12 pages, Revtex (to appear in Physical Review Letters

Developing core sets for persons following amputation based on the International Classification of Functioning, Disability and Health as a way to specify functioning

Amputation is a common late stage sequel of peripheral vascular disease and diabetes or a sequel of accidental trauma, civil unrest and landmines. The functional impairments affect many facets of life including but not limited to: Mobility; activities of daily living; body image and sexuality. Classification, measurement and comparison of the consequences of amputations has been impeded by the limited availability of internationally, multiculturally standardized instruments in the amputee setting. The introduction of the International Classification of Functioning, Disability and Health (ICF) by the World Health Assembly in May 2001 provides a globally accepted framework and classification system to describe, assess and compare function and disability. In order to facilitate the use of the ICF in everyday clinical practice and research, ICF core sets have been developed that focus on specific aspects of function typically associated with a particular disability. The objective of this paper is to outline the development process for the ICF core sets for persons following amputation. The ICF core sets are designed to translate the benefits of the ICF into clinical routine. The ICF core sets will be defined at a Consensus conference which will integrate evidence from preparatory studies, namely: (a) a systematic literature review regarding the outcome measures of clinical trails and observational studies, (b) semi-structured patient interviews, (c) international experts participating in an internet-based survey, and (d) cross-sectional, multi-center studies for clinical applicability. To validate the ICF core sets field-testing will follow. Invitation for participation: The development of ICF Core Sets is an inclusive and open process. Anyone who wishes to actively participate in this process is invited to do so

Constraints on Light Pseudoscalars Implied by Tests of the Gravitational Inverse-Square Law

The exchange of light pseudoscalars between fermions leads to a spin-independent potential in order g^4, where g is the Yukawa pseudoscalar-fermion coupling constant. This potential gives rise to detectable violations of both the weak equivalence principle (WEP) and the gravitational inverse-square law (ISL), even if g is quite small. We show that when previously derived WEP constraints are combined with those arisingfrom ISL tests, a direct experimental limit on the Yukawa coupling of light pseudoscalars to neutrons can be inferred for the first time (g_n^2/4pi < 1.6 \times 10^-7), along with a new (and significantly improved) limit on the coupling of light pseudoscalars to protons.Comment: 12 pages, Revtex, with 1 Postscript figure (submitted to Physical Review Letters

If Practice Makes Perfect, Where do we Stand?

Practitioners have played an important role in the information system (IS) field’s development since its beginnings. In the 1970s, IS researchers’ integration with practitioners was high with Society for Information Management members receiving copies of the MIS Quarterly, practitioners funding the ICIS Doctoral Consortium, and submissions receiving at least one practitioner review. Today, however, the integration between practitioners and researchers appears more distant. Given that almost 50 years have passed since the field’s development, we believe that we need to reflect on the past, present, and future relationship between IS research and IS practice. Has the distance between academics and practitioners become too great? Is our relevance too low to expect practitioners to join AIS and attend our conferences? How might we increase the integration? At a panel at ICIS 2018, several panelists provided position statements about those issues

Geometric Random Inner Products: A New Family of Tests for Random Number Generators

We present a new computational scheme, GRIP (Geometric Random Inner Products), for testing the quality of random number generators. The GRIP formalism utilizes geometric probability techniques to calculate the average scalar products of random vectors generated in geometric objects, such as circles and spheres. We show that these average scalar products define a family of geometric constants which can be used to evaluate the quality of random number generators. We explicitly apply the GRIP tests to several random number generators frequently used in Monte Carlo simulations, and demonstrate a new statistical property for good random number generators

Competition, predation, and migration: individual choice patterns of Serengeti migrants captured by hierarchical models

Large-herbivore migrations occur across gradients of food quality or food abundance that are generally determined by underlying geographic patterns in rainfall, elevation, or latitude, in turn causing variation in the degree of interspecific competition and the exposure to predators. However, the role of top-down effects of predation as opposed to the bottom-up effects of competition for resources in shaping migrations is not well understood. We studied 30 GPS radio-collared wildebeest and zebra migrating seasonally in the Serengeti-Mara ecosystem to ask how predation and food availability differentially affect the individual movement patterns of these co-migrating species. A hierarchical analysis of movement trajectories (directions and distances) in relation to grass biomass, high-quality food patches, and predation risk show that wildebeest tend to move in response to food quality, with little attention to predation risk. In contrast, individual zebra movements reflect a balance between the risk of predation and the access to high-quality food of sufficient biomass. Our analysis shows how two migratory species move in response to different attributes of the same landscape. Counterintuitively and in contrast to most other animal movement studies, we find that both species move farther each day when resources are locally abundant than when they are scarce. During the wet season when the quality of grazing is at its peak, both wildebeest and zebra move the greatest distances and do not settle in localized areas to graze for extended periods. We propose that this punctuated movement in highquality patches is explained by density dependency, whereby large groups of competing individuals (up to 1.65 million grazers) rapidly deplete the localized grazing opportunities. These findings capture the roles of predation and competition in shaping animal migrations, which are often claimed but rarely measured