نتایج جستجو برای: drying shrinkage

تعداد نتایج: 36314  

Journal: :پژوهش های علوم و فناوری چوب و جنگل 0

in this research, the influence of red heartwood formation in iranian beech (fagus orientalis l.) on its drying behavior was studied. radial variation (from pith to bark) in specific gravity, green moisture content, drying rate, transverse shrinkage and casehardening in a beech log containing red heartwood was investigated. all samples were dried in an experimental kiln under a constant tempera...

2016
Jianxia Liu Ximing Wang

As wood shrinks during the drying process, various stresses may develop and cause surface and internal checking. The aim of this study was to systematically investigate the effect of the drying temperature, relative humidity, and specimen thickness on the contraction stress in elm wood (Ulmus pumila L.) specimens during drying. The contraction stress was used as an indirect indicator of drying ...

A. Kaveh, S. M. Hamze-Ziabari, T. Bakhshpoori,

In the present study, the multivariate adaptive regression splines (MARS) technique is employed to estimate the drying shrinkage of concrete. To this purpose, a very big database (RILEM Data Bank) from different experimental studies is used. Several effective parameters such as the age of onset of shrinkage measurement, age at start of drying, the ratio of the volume of the sample on its drying...

2013
Muhammad Burhan Sharif Abdullah Anjum Muhammad Akram Tahir Muhammad Yousaf

Concrete is probably the most extensively used construction material in the world. However, environmental concerns regarding rapid consumption of natural resources and CO2 emission during cement manufacturing process have brought pressure to reduce cement consumption by the use of cement replacement materials (CRMs). The utilization of calcined clay (metakaolin) and silica fume in concrete has ...

2014
Lin Yang Hong-Hai Liu Ying-chun Cai Kazuo Hayashi Kai-Fu Li

To explore the collapse of eucalyptus wood cells during the drying process, continuous and intermittent drying were carried out on Eucalyptus urophylla. The shrinkage throughout the intermittent drying process was less than that of continuous drying. According to observations of cells made using scanning electron microscopy (SEM), there was a large difference in the degree of cell collapse betw...

Journal: :international journal of civil engineering 0
h. famili narmac civil engineering dept. m. khodadad saryazdi yazd safaeayah civil eng. dept. t. parhizkar tehran bhrc

self-desiccation is the major source of autogenous shrinkage and crack formation in low water-binder ratio (w/b) concretes which can be reduced by internal curing. in this paper performance of high strength self consolidating concrete (hs-scc) with w/b of 0.28 and 0.33 including autogenous shrinkage, drying shrinkage, compressive strength, and resistance to freezing-thawing was investigated. th...

Journal: :Journal of nanoscience and nanotechnology 2012
L Durães M Ochoa N Rocha R Patrício N Duarte V Redondo A Portugal

Nanostructured silica based xerogels and aerogels are prepared by sol-gel technology, using methyltrimethoxysilane as precursor. The influence of the drying method and conditions on the microstructure of the obtained materials is investigated, since the drying stage has a critical influence on their porosity. Two types of drying methods were used: atmospheric pressure drying (evaporative), to p...

Journal: :Acta scientiarum polonorum. Technologia alimentaria 2015
Behnam Alaei Reza Amiri Chayjan

BACKGROUND Drying of nectarine slices was performed to determine the thermal and physical properties in order to reduce product deterioration due to chemical reactions, facilitate storage and lower transportation costs. Because nectarine slices are sensitive to heat with long drying period, the selection of a suitable drying approach is a challenging task. Infrared-vacuum drying can be used as ...

Journal: :NIPPON SUISAN GAKKAISHI 1962

2015
Tommy Atkins

Abstract—High moisture content in fruits generates post-harvest problems such as mechanical, biochemical, microbial and physical losses. Dehydration, which is based on the reduction of water activity of the fruit, is a common option for overcoming such losses. However, regular hot air drying could affect negatively the quality properties of the fruit due to the long residence time at high tempe...

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