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Article
Publication date: 28 June 2019

Shuang Huang, Xin Wu and Peixing Li

In the textile industry, liquid ammonia treatment is an important way to modify the structure of natural fibers. The purpose of this paper is to reveal the diffusion behaviors of…

179

Abstract

Purpose

In the textile industry, liquid ammonia treatment is an important way to modify the structure of natural fibers. The purpose of this paper is to reveal the diffusion behaviors of liquid ammonia in cellulose.

Design/methodology/approach

To analysis the diffusion behaviors of liquid ammonia in cellulose, the cellulose model and the system of ammonia and cellulose are built. Infrared spectrum is carried out to test the model of cellulose, which is found to agree with experiment. Diffusion coefficients, free volume and hydrogen bonds are discussed to explain diffusion behaviors.

Findings

The results demonstrate that diffusion coefficients and free volume of systems rise with increasing temperature. The diffusion coefficients of ammonia are larger than those of water, a result in agreement with free volume. To understand the mechanism of diffusion, the numbers of hydrogen bonds are tracked. It is found that without ammonia, intrachain hydrogen bonds decrease with the increase of temperature, which indicate that the structural stability of cellulose is deteriorated. And the increased interchain hydrogen bonds show that swelling properties of cellulose become better with the increase of temperature. After ammonia treatment, the numbers of intrachain hydrogen bonds remain stable, indicating that the structure stability of cellulose chain is maintained. But, there is a substantial rupture of interchain hydrogen bonds, ammonia molecule destroys the hydrogen bond network between the original cellulose molecular chains, which intensifies the activity of cellulose molecular chains and enlarges the distance between cellulose molecular chains, showing good swelling properties.

Originality/value

The research findings give a detailed information about the diffusion behaviors of liquid ammonia in cellulose, which provide the theoretical evidence for liquid ammonia treatment.

Details

International Journal of Clothing Science and Technology, vol. 31 no. 5
Type: Research Article
ISSN: 0955-6222

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Article
Publication date: 16 January 2023

Gregory Stock and Christopher McDermott

The authors examine how physician staffing, human capital and knowledge spillovers are related to multiple dimensions of hospital operational and financial performance at the…

530

Abstract

Purpose

The authors examine how physician staffing, human capital and knowledge spillovers are related to multiple dimensions of hospital operational and financial performance at the organizational level.

Design/methodology/approach

The authors use a data set assembled from multiple sources for more than 1,300 US hospitals and employ hierarchical linear regression to test this study’s hypotheses. The authors use multiple quality, efficiency and financial measures of performance for these hospitals.

Findings

The authors find that higher levels of staffing, skills and knowledge spillovers associated with physicians were positively associated with multiple dimensions of hospital performance. The authors find linear and nonlinear relationships between experience and performance, with the relationships primarily negative, and nonlinear relationships between spillovers and quality performance.

Practical implications

Hospital managers should consider increasing physician staffing levels if possible. In addition, the overall Final MIPS Score from the Centers for Medicare and Medicaid Services might be included as a factor in determining which physicians practice in a hospital. Finally, if possible, encouraging physicians to practice at multiple hospitals will likely be beneficial to hospital performance.

Originality/value

This study’s findings are original in that they explore how physician-specific staffing and human capital, which have received comparatively little attention in the literature, are related to several different dimensions of hospital-level operational and financial performance. To the best of the authors’ knowledge, this paper is also the first to examine the relationship between the construct of physician knowledge spillovers and hospital-level operational and financial performance.

Details

International Journal of Operations & Production Management, vol. 43 no. 7
Type: Research Article
ISSN: 0144-3577

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Article
Publication date: 16 January 2017

Yanjin Lu, Yiliang Gan, Junjie Lin, Sai Guo, Songquan Wu and Jinxin Lin

The aim of the study is to obtain dense Ni-free CoCrW parts fabricated by selective laser melting (SLM) technique for dental application.

589

Abstract

Purpose

The aim of the study is to obtain dense Ni-free CoCrW parts fabricated by selective laser melting (SLM) technique for dental application.

Design/methodology/approach

The optimum of processing CoCrW powders was investigated by the varying laser scanning speeds between 200 and 1,500 mm/s with the other parameters fixed as constants. The investigations of density, phase, mechanical property and corrosion resistance were conducted.

Findings

It was found that a maximum relative density of 99.4 per cent was obtained with the preferable laser scanning speed of 700 mm/s; the outcome from the tensile test suggested that the 0.2 per cent yield strength of the specimen fabricated at 700 mm/s satisfied the type 5 criteria in ISO22764 for dental application, whereas the electrochemical test indicated that the specimens fabricated at 700 mm/s existed excellent corrosion resistance. The high precision dental denture could be fabricated by SLM.

Originality/value

In the study, the Ni-free CoCrW parts fabricated by SLM was investigated by the tensile and electrochemical tests. The yield strength, corrosion resistance and margin fit accuracy met requirements for dental application. It was considered that the speed of 700 mm/s with the laser powers of 95 W, the track width of 0.11 mm and the layer thickness of 25 μm are promising candidates for fabricating the CoCrW parts.

Details

Rapid Prototyping Journal, vol. 23 no. 1
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 23 May 2022

Ghadeer Alabbadi and Rabab Allouzi

The purpose of this study is to improve the lateral capacity of Cold-Formed Steel (CFS) frame walls filled with lightweight foamed concrete (LFC) and supported with straw boards…

66

Abstract

Purpose

The purpose of this study is to improve the lateral capacity of Cold-Formed Steel (CFS) frame walls filled with lightweight foamed concrete (LFC) and supported with straw boards by introducing structural foamed concrete and/or bracing.

Design/methodology/approach

Finite element models are developed and calibrated based on previous experimental work. Then, these models are extended to conduct a parametric study to quantify the effect of filling CFS walls and structural LFC and the effect of supporting CFS walls with bracing.

Findings

Results of the study conclude that the finite element analysis can be used to simulate and analyze the lateral capacity of CFS walls effectively since the maximum deviation between calibrated and experimental results is 10%. The structural LFC usage in CFS walls improves the lateral capacity considerably by (25–75) % depending on the wall properties. Besides, the application of lateral bracing does not always have a positive effect on the lateral performance of these walls.

Originality/value

Although CFS walls are preferred due to it is light in weight, low in cost, easy to install and recyclable, low seismic performance, buckling vulnerability, poor thermal insulation and sound insulation properties, low lateral stiffness, and low shear strength limit their use. This study proposes the use of structural foamed concrete and a different bracing method than what is available in the literature. This can overcome the drawbacks of the CFS walls alone which can permit the usage of such walls in mid-rise buildings and other applications.

Details

International Journal of Structural Integrity, vol. 13 no. 4
Type: Research Article
ISSN: 1757-9864

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