Richard Steele

Some Theoretical Considerations of Cellulose Cross-Linking

Much available chemical evidence supports the hypothesis that covalent cross-linking is the best way to improve the resilience of cellulosic fabrics. This paper reviews the theories relating physical properties to cross-linking in rubbery polymers and shows that they apply in some qualitative aspects to cellulose. Particularly, the observed changes in swelling, solubility, modulus, tensile strength, and resilience are consistent with these theories. On the basis of published data, the concentration of intermolecular cross links is esti mated ; it is found that at least every twenty-fifth accessible anhydroglucose unit has to be intermolecularly cross-linked when maximum crease recovery values are attained. In rubbery polymers, substantial changes in mechanical properties are obtained at much lower levels of cross-linking. This difference between cellulose and rubbers in response to cross-linking is probably due to the polar nature of cellulose.

The Relation of Wet and Dry Crease Recovery to Wash -Wear Behavior

The chemical changes in cellulose fiber which lead to various wet: dry crease re- , covery ratios are reviewed. Covalent cross-linking of a dry fiber enhances both wet and dry recovery, and the ratio of the two values is believed to depend on the relative accessibilities of the fiber to water and to the cross-linking reagent. Water-sensitive links between cellulose chains can give high dry and low wet crease recovery. Cross- linking reactions carried out when the fiber is wet and swollen lead to a higher degree of intrachain reaction, which is equivalent to substitution, and to some interchain cross links. The swelling of such a fiber in water leads to good wet crease recovery, although the dry recovery is not improved. To achieve good tumble-dry wash-wear behavior, both wet and dry crease recovery must be increased In line- and drip-drying, the we crease recovery has more sig nificance than the dry.

Relationships between impairment-level assessments and functional-level assessments in aphasia: Findings from LCC treatment programmes

We report an outcome study of persons with aphasia participating in community-based treatment programmes. Patients (n = 50) were assessed before and after treatment using: (i) a standardised test of impairment, the Western Aphasia Battery, administered by treating clinicians; and (ii) a standardised assessment of disability (functional communication), the Communicative Effectiveness Index, rated by family members. Pretreatment and post-treatment means are calculated and compared, with matched t -tests utilised to probe statistical significance of improvements after treatment. We then calculate impairment- and functional-level means by aphasia diagnostic categories, assigning rank orders and calculating Spearman rank-order correlations. Data analysis shows that, before treatment, patients spanned a wide range of times after onset, aphasia diagnostic types, and severity levels at start of care. Following treatment, means of the 50 patients improved significantly on every measure administered at both the impairment and the functional levels. Absolute improvements ranged from 6.5% to 26.2%, with statistical significance ranging from p < .01 to p << .0001. Before treatment, there is strong positive correlation (𝜌 = +.90) between impairment-level and functional-level assessment means by diagnostic categories; after treatment, improvement means by these diagnostic categories show moderate negative correlation (𝜌 =-.60). Further examination shows that post-treatment improvements are found to be best viewed as functions of same-type severity levels pretreatment, with patterns of improvement at the impairment and functional levels diverging distinctly.

The Reaction of Forxnaldehyde with Cellulose

the useful effects it can produce on the physical and mechanical properties of cellulosic fibers. The chemistry of the reaction has been studied by a number of workers. The work before 1942 is reviewed by Schaeffer [6], while Gruntfest and Gagliardi [2] have more recently examined the problem. The author has made some observations in the rock salt region of the infrared spectrum which he believes may contribute to understanding this reaction.

Telepractice in the Assessment and Treatment of Individuals with Aphasia: A Systematic Review

Telepractice involves the application of technology to deliver services over a geographical distance. Studies in which telepractice procedures were used in the assessment or treatment of individuals with aphasia were reviewed. Systematic searches identified 10 studies meeting inclusion criteria. These studies were evaluated in terms of the: (a) characteristics of the participants, (b) technology utilized (c), services delivered via telepractice, (d) research methodology, and (e) results and conclusions of the study. Telepractice was used by speech-language pathologists and allied health professionals to assist with the delivery of services to participants with aphasia by their caretakers or clinicians. The services delivered included appraisal, diagnostic assessments, interventions, and consultation. This review suggests that telepractice is a viable method of service delivery for individuals with aphasia, however further research is warranted. Guidelines for practitioners and potential directions for future research are discussed.

Representations of ‘verbs’ in a computerized visual communication system

Abstract versus concrete representations for verbs in a visual, non-verbal communication system for severe aphasics were investigated. Two patients with comparable agrammatic aphasias were studied in paired counter-balanced experiments. Concrete symbols were learned more quickly and generalized slightly faster to apply to new objects. However, neither abstract nor concrete symbols were generalized very well to novel situations. The implications for the organization of semantic information in aphasic patients and for future research on visual communication systems are discussed.

An Analysis of Tearing Failure

The tearing failure of materials depends very strongly on the conditions of use or testing which produce the non-uniform tensile stress which causes such failure. In the trapezoid tear test. the stress pattern is determined largely by variables at the disposition of the operator. The effect of these variables on the tearing strength and the relationship of the latter to the shape of the force-elongation curve have been determined. The tear load is given by an equation of the form where g is the modulus. h is the thickness. L o is the gauge length, α is the trapezoid angle. and E is the elongation of the material at break. The form of the term f( E) is deter mined by the shape of the force-elongation curve and has been calculated for the linear case and for cases yielding convex and concave curves. The validity of this equation has been evaluated with experiments on cotton and rayon fabries in which gauge length, trapezoid angle, thickness and elongation were varied The data are reasonably well tit by the equation using the form of f( E) calculated for a linear force-elongation curve.

Computers in the rehabilitation of chronic, severe aphasia: C-VIC 2.0 cross-modal studies

Abstract We describe the C-VIC 2.0 system for use by severe, chronic aphasic patients, and give an account of its use in helping a globally aphasic patient in a cooking-related task. In this controlled study, we conducted cross-modal comparisons of acontextual execution of single steps, delivered in C-VIC, spoken, and written modalities. We report results of the experiment, and discuss the findings along with some of their possible implications.

Evaluation and Treatment of Aphasia Among the Elderly With Stroke

&NA; While aphasia is not per se a geriatric disorder, risk factors for aphasia increase with age, and effective treatments for older individuals must be sensitive to age‐related needs and circumstances. This article first reviews evaluation tools, with their assessment domains and ways of using them, then moves to treatment approaches, with an eye in particular to describing experiences using advanced treatment programs with older aphasic patients, and concludes with discussions and examples of outcomes analyses that contribute to our understanding of improvements following treatment in older patients.

A Method for Studying the Deformation of Fabrics in Creasing

A procedure has been devised for obtaining the load-deformation curve of a fabric during a deformation which begins as a small-radius bend and ends in crease formation. A strip of the fabric is formed, into a cylinder and mounted horizontally on the crosshead of an Instron tester. A fixed weight is hung from the strain gauge and the force exerted on the bottom of this weight as the sample cylinder moves up against it is recorded by the tester. The recovery curve can be obtained by reversing the crosshead. The results are most conveniently presented by plotting log of the jaw separation against the re ciprocal of the load. Curves obtained in this way on a variety of fabrics, including some resin-finished ones, indicate that the procedure should be of value in studying stiffness, resilience, crease recovery, and other properties related to the drape and handle of fabrics.