Search results

1 – 10 of over 2000
Article
Publication date: 30 March 2010

Mingguo Tang, Kamran Alvani and Richard F. Tester

The purpose of this paper is to prepare alginate‐pectin‐starch containing matrices expanded by the generation of carbon dioxide, from carbonates when in contact with acids…

Abstract

Purpose

The purpose of this paper is to prepare alginate‐pectin‐starch containing matrices expanded by the generation of carbon dioxide, from carbonates when in contact with acids, characterise their structure in vitro and to assess their capacity to provide satiety in vivo.

Design/methodology/approach

For in vitro characterisation, carbon dioxide expanded polysaccharide matrices (rafts) were prepared in HCl and their structural strength was measured in terms of their capacity to resist breakage in a model test system. For in vivo trials, 12 healthy volunteers (mixed sex, aged 25‐55) were recruited to take part in the three‐part trial. Each part lasted for one week where volunteers consumed polysaccharides (in 50 ml water) with or without rafting salts (carbonates), or water (as a control). Effects on satiety, reduction of food intake and any change to body weight were evaluated with the volunteers.

Findings

The in vitro results showed that aqueous solution/dispersions (50 ml) of alginate‐pectin‐starch matrices produced rafts in hydrochloric acid (pH < 2), where increasing the ratio of carbonates to polysaccharides (range from 0.25:1 to 1.5:1, w/w) provided increased floatation capability but reducing gel strength. These rafts were stable for over 24 h at room temperature within 0.05‐0.5 M HCl. For in vivo “satiety” studies, when volunteers consumed (daily) aliquots of the polysaccharide mixture plus flavour and sweetener without carbonates 2.5 h after lunch, they felt the onset of hunger on average 186 ± 68 min after consumption of the polysaccharides. This was not significantly different from a water only control (onset of hunger at 165 ± 47 min). When polysaccharides plus flavour sweetener and carbonates were consumed, however, volunteers reported feeling the onset of hunger at 224 ± 62 min on average after consumption which was significantly different from the water control (p < 0.001), or the polysaccharides without carbonates (p < 0.01). When consuming the polysaccharide rafting format, half of the volunteers reported a reduction in size of their evening meal.

Originality/value

These data indicate that the alginate‐pectin‐starch combination with carbonate salts in a “gastric rafting format” provide a potential approach in the management of body weight and obesity.

Details

Nutrition & Food Science, vol. 40 no. 2
Type: Research Article
ISSN: 0034-6659

Keywords

Article
Publication date: 8 September 2023

Xing Ai, Shuaishuai Wang, Fenghua Luo, Haiqing Pei and Zhenwei Li

The purpose of this study is to describe the mechanism of single-crystal high-temperature creep deformation, predict the creep life more accurately and study the creep…

Abstract

Purpose

The purpose of this study is to describe the mechanism of single-crystal high-temperature creep deformation, predict the creep life more accurately and study the creep constitutive and lifetime models with microstructure evolution.

Design/methodology/approach

The mechanical properties of nickel-based single-crystal superalloy are closely related to the γ' phase. Creep tests under four different temperature and stress conditions were carried out. The relationship between creep temperature, stress and life is fitted by numerical method, and the creep activation energy is obtained. The creep fracture surface, morphology and evolution of strengthening phase (γ') and matrix phase (γ) during different creep periods were observed by scanning electron microscope. With the increase of creep temperature, the rafting time is advanced. The detailed morphology and evolution of dislocations were observed by transmission electron microscope (TEM).

Findings

With the increase of creep temperature, the rafting time is advanced. The detailed morphology and evolution of dislocations were observed by TEM. Dislocations are mainly concentrated in the γ channel phase, especially at high temperature and low stress.

Originality/value

A creep constitutive model based on the evolution of γ' phase size and γ channel width was proposed. Compared with the experimental results, the predicted creep life is within 1.4 times error dispersion band.

Details

Multidiscipline Modeling in Materials and Structures, vol. 19 no. 6
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 26 June 2020

Haojia Su, Zhengchun Cai, Zhengwei lv, Yongkang Chen and Yongxin Ji

In this work, the authors used reversible addition-fragmentation transfer (RAFT) polymerization to develop a new cationic acrylate modified epoxy resin emulsion for water-borne…

Abstract

Purpose

In this work, the authors used reversible addition-fragmentation transfer (RAFT) polymerization to develop a new cationic acrylate modified epoxy resin emulsion for water-borne inkjet which have the advantages of both polyacrylate and epoxy resin. The emulsion was successfully used in the canvas coating for inkjet printing. This paper aims to contribute to the development of novel cationic emulsions for inkjet printing industry.

Design/methodology/approach

In this work, the epoxy acrylate was synthesized from RAFT agent and epoxy resin firstly. Cationic macromolecular emulsifier was prepared by RAFT polymerization, using 2,2’-Azobisisobutyronitrile as initiator, 2-(dimethylamino)ethyl methacrylate and styrene as monomer, which was directly used to prepare the emulsion. The influences of the amount of 2-(dimethylamino)ethyl methacrylate on particle size, zeta potential and water contact angle were studied. Finally, the cationic emulsion was used to print images by inkjet printing.

Findings

The emulsion has the smallest particle size, the highest potential and the highest water contact angle when the DM content is 13 Wt.%. The transmission electron microscopy analysis reveals the latex particles is core-shell sphere with the diameters in the range 120–200 nm. The emulsion was successfully used in the canvas coating for inkjet printing. This work will contribute to the development of novel cationic emulsions for inkjet printing industry.

Originality/value

The emulsion was successfully used in the canvas coating for inkjet printing. This work will contribute to the development of novel cationic emulsions for inkjet printing industry.

Details

Pigment & Resin Technology, vol. 49 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 1 August 2000

Hugo Letiche and René van Hattem

A normative hurdle needs to be taken of moving beyond claims that relationship(s) of exploitation (neo‐Marxism) and bureaucracy (neo‐Weberian) are determinate, and that there is…

2759

Abstract

A normative hurdle needs to be taken of moving beyond claims that relationship(s) of exploitation (neo‐Marxism) and bureaucracy (neo‐Weberian) are determinate, and that there is nothing new under the sun. Descriptive research is needed into what is new in the knowledge work economy/society. New relationships between self and organization demand the rethinking of logocentricism. In knowledge work, management by content mobilizes the self via individualist and creative work. An organizational (epistemic) regime emerges where the claim on the self is total. Ethnographic research has revealed self/organization identification, wherein the identification of the two leads via divergence and conflict to (organizational) fragmentation. Kunda has shown that self/organization identification can endanger the self through burn‐out and an unhealthy fixation on work. Establishes that identification between self and organization can endanger necessary boundary objects threatening requisite meanings and structures.

Details

Journal of Organizational Change Management, vol. 13 no. 4
Type: Research Article
ISSN: 0953-4814

Keywords

Open Access
Article
Publication date: 3 February 2021

Geoff A.M. Loveman and Joel J.E. Edney

The purpose of the present study was the development of a methodology for translating predicted rates of decompression sickness (DCS), following tower escape from a sunken…

Abstract

Purpose

The purpose of the present study was the development of a methodology for translating predicted rates of decompression sickness (DCS), following tower escape from a sunken submarine, into predicted probability of survival, a more useful statistic for making operational decisions.

Design/methodology/approach

Predictions were made, using existing models, for the probabilities of a range of DCS symptoms following submarine tower escape. Subject matter expert estimates of the effect of these symptoms on a submariner’s ability to survive in benign weather conditions on the sea surface until rescued were combined with the likelihoods of the different symptoms occurring using standard probability theory. Plots were generated showing the dependence of predicted probability of survival following escape on the escape depth and the pressure within the stricken submarine.

Findings

Current advice on whether to attempt tower escape is based on avoiding rates of DCS above approximately 5%–10%. Consideration of predicted survival rates, based on subject matter expert opinion, suggests that the current advice might be considered as conservative in the distressed submarine scenario, as DCS rates of 10% are not anticipated to markedly affect survival rates.

Originality/value

According to the authors’ knowledge, this study represents the first attempt to quantify the effect of different DCS symptoms on the probability of survival in submarine tower escape.

Details

Journal of Defense Analytics and Logistics, vol. 5 no. 1
Type: Research Article
ISSN: 2399-6439

Keywords

Article
Publication date: 15 November 2011

Volker G. Kuppelwieser and Jörg Finsterwalder

This paper aims to demonstrate how psychological safety influences individual contributions in customer groups where multiple customers co‐create a service experience. It also…

2512

Abstract

Purpose

This paper aims to demonstrate how psychological safety influences individual contributions in customer groups where multiple customers co‐create a service experience. It also shows the influence of other customers' contributions on an individual customer's own contribution to the service experience as well as the individual customer's perception of his/her own and of other customers' contributions toward service satisfaction.

Design/methodology/approach

This empirical research paper is based on structural equation modelling to examine customer group experiences of two different service providers, a white water rafting company and an indoor soccer company. Data from a survey of a combined total of 273 consumers were utilised to test the research model.

Findings

The results demonstrate that, on an aggregate level, psychological safety affects an individual customer's perception of his/her own and others' contributions to a service experience. The findings show that the contributions of others have a significant influence on one's own contribution. No influence or relationship could be found regarding one's own contribution and service satisfaction; however, other customers' contributions have a negative effect on an individual's service satisfaction. The results vary on a subsample level.

Research limitations/implications

The generalisability of the findings is limited to two customer group services, one group sport experience and one group leisure experience.

Practical implications

This research provides insights for service firms with respect to managing the provider‐to‐multi‐customer co‐creation interface.

Originality/value

This article contributes to the analysis of co‐creation efforts of individuals in groups with respect to a specific environment (psychological safety). It adds value to the discussion of factors that influence the partial creation of a service by individuals while interacting with one another and the impact on the perceived outcome. The paper provides a platform for further research on aspects of co‐creation in customer groups.

Details

Managing Service Quality: An International Journal, vol. 21 no. 6
Type: Research Article
ISSN: 0960-4529

Keywords

Article
Publication date: 27 September 2022

Mingyue Xie, Jun Liu, Shuyu Chen and Mingwei Lin

As the core technology of blockchain, various consensus mechanisms have emerged to satisfy the demands of different application scenarios. Since determining the security…

Abstract

Purpose

As the core technology of blockchain, various consensus mechanisms have emerged to satisfy the demands of different application scenarios. Since determining the security, scalability and other related performance of the blockchain, how to reach consensus efficiently of consensus mechanism is a critical issue in the blockchain.

Design/methodology/approach

The paper opted for a research overview on the blockchain consensus mechanism, including the consensus mechanisms' consensus progress, classification and comparison, which are complemented by documentary analysis.

Findings

This survey analyzes solutions for the improvement of consensus mechanisms in blockchain that have been proposed during the last few years and suggests future research directions around consensus mechanisms. First, the authors outline the consensus processes, the advantages and disadvantages of the mainstream consensus mechanisms. Additionally, the consensus mechanisms are subdivided into four types according to their characteristics. Then, the consensus mechanisms are compared and analyzed based on four evaluation criteria. Finally, the authors summarize the representative progress of consensus mechanisms and provide some suggestions on the design of consensus mechanisms to make further advances in this field.

Originality/value

This paper summarizes the future research development of the consensus mechanisms.

Details

International Journal of Intelligent Computing and Cybernetics, vol. 16 no. 2
Type: Research Article
ISSN: 1756-378X

Keywords

Article
Publication date: 27 January 2022

Michelle Kwok

Although English Language Arts (ELA) teachers have historically been expected to take the lead in literacy training, the domain of ELA has yet come to terms with what holds it…

Abstract

Purpose

Although English Language Arts (ELA) teachers have historically been expected to take the lead in literacy training, the domain of ELA has yet come to terms with what holds it together as a discipline. Within this conundrum, the author studied one group of ELA teacher leaders who led a professional development (PD) aimed at training teachers in disciplinary writing instruction. This study aims to explore the differences in perspectives between what constitutes disciplinarity for ELA teachers and teachers in other content areas.

Design/methodology/approach

Over the course of two years, the author observed the PD, taking extensive field notes, collecting artifacts and conducting interviews. The author engaged in constant comparative analysis of the data throughout this time, open coding within each data source and then triangulating the data to support the author’s finding.

Findings

Whereas the ELA teacher leaders seemed to focus on general aspects of writing, teachers from the other content areas shared discipline-specific understandings about writing. The teachers and teacher leaders, however, did not explicitly discuss these differences in how they conceptualized writing instruction; rather, this tension was revealed through the author’s analysis of the data.

Originality/value

The findings of this study illustrate how a vague definition of writing in English and of disciplinary literacy has come to bear on one PD of writing. This study recommends future research to continue to develop clear epistemologies, purposes and literate practices of the disciplines related to ELA.

Details

English Teaching: Practice & Critique, vol. 21 no. 1
Type: Research Article
ISSN: 1175-8708

Keywords

Article
Publication date: 1 December 2023

Wan Xu, Xinsheng Liu, Huijuan Zhang, Ting Huo, Zhenbin Chen and Yuan Sun

This study aims to prepare an imprinted composite membrane with grafted temperature-sensitive blocks for the efficient adsorption and separation of rhenium(Re) from aqueous…

Abstract

Purpose

This study aims to prepare an imprinted composite membrane with grafted temperature-sensitive blocks for the efficient adsorption and separation of rhenium(Re) from aqueous solutions.

Design/methodology/approach

PVDF resin membrane was used as the substrate, dopamine and chitosan (CS) were used to modify the membrane surface and temperature-sensitive block PDEA was grafted on the membrane surface. Then acrylic acid (AA) and N-methylol acrylamide (N-MAM) were used as the functional monomers, ethyleneglycol dimethacrylate (EGDMA) as the cross-linker and ascorbic acid-hydrogen peroxide (Vc-H2O2) as the initiator to obtain the temperature-sensitive ReO4 imprinted composite membranes.

Findings

The effect of the preparation process on the performance of CS–Re–TIICM was investigated in detail, and the optimal preparation conditions were as follows: the molar ratios of AA–NH4ReO4, N-MAM and EGDMA were 0.13, 0.60 and 1.00, respectively. The optimal temperature and time of the reaction were 40 °C and 24 h. The maximum adsorption capacity of CS–Re–TIICM prepared under optimal conditions was 0.1071 mmol/g, and the separation was 3.90 when MnO4 was used as the interfering ion. The quasi first-order kinetics model and Langmuir model were more suitable to describe the adsorption process.

Practical implications

With the increasing demand for Re, the recovery of Re from Re-containing secondary resources becomes important. This study demonstrated a new material that could be separated and recovered Re in a complex environment, which could effectively alleviate the conflict between the supply and demand of Re.

Originality/value

This contribution provided a new material for the selective separation and purification of ReO4, and the adsorption capacity and separation of CS–Re–TIICM were increased with 1.673 times and 1.219 time compared with other Re adsorbents, respectively. In addition, when it was used for the purification of NH4ReO4 crude, the purity was increased from 91.950% to 99.999%.

Details

Pigment & Resin Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0369-9420

Keywords

Open Access
Article
Publication date: 22 December 2022

Carolina Bermudo Gamboa, Sergio Martín Béjar, Francisco Javier Trujillo Vilches and Lorenzo Sevilla Hurtado

The purpose of this study is to cover the influence of selected printing parameters at a macro and micro-geometrical level, focusing on the dimensions, geometry and surface of…

Abstract

Purpose

The purpose of this study is to cover the influence of selected printing parameters at a macro and micro-geometrical level, focusing on the dimensions, geometry and surface of printed parts with short carbon fibers reinforced PLA. For this case study, a hollow cylindrical shape is considered, aiming to cover the gap detected in previous works analyzed.

Design/methodology/approach

Nowadays, additive manufacturing plays a very important role in the manufacturing industry, as can be seen through its numerous research and applications that can be found. Within the engineering industry, geometrical tolerances are essential for the functionality of the parts and their assembly, but the variability in three-dimensional (3D) printing makes dimensional control a difficult task. Constant development in 3D printing allows, more and more, printed parts with controlled and narrowed geometrical deviations and tolerances. So, it is essential to continue narrowing the studies to achieve the optimal printed parts, optimizing the manufacturing process as well.

Findings

Results present the relation between the selected printing parameters and the resulting printed part, showing the main deviations and the eligible values to achieve a better tolerance control. Also, from these results obtained, we present a parametric model that relates the geometrical deviations considered in this study with the printing parameters. It can provide an overview of the piece before printing it and so, adjusting the printing parameters and reducing time and number of printings to achieve a good part.

Originality/value

The main contribution is the study of the geometry selected under a 3D printing process, which is important because it considers parts that are created to fit together and need to comply with the required tolerances. Also, we consider that the parametric model can be a suitable approach to selecting the optimal printing parameters before printing.

Details

Rapid Prototyping Journal, vol. 29 no. 11
Type: Research Article
ISSN: 1355-2546

Keywords

1 – 10 of over 2000