Effects of loading conditions and specimen thickness on the flexural behavior of fiber-reinforced cementitious composites

The flexural performance of polypropylene (PP) and polyvinyl alcohol (PVA) fiber reinforced cementitious composites (FRCC) have been investigated within the scope of this study. Thin plates and relatively thicker prismatic specimens have been prepared by using three fiber-matrix combinations. The center-point and two-point loading flexural performance of these specimens has been determined in terms of; first cracking strength, flexural strength and toughness. Test results showed that there is a significant difference in the flexural properties and toughness between thin specimens (mini-plates; thickness/span = 0.08) incorporating PP and PVA fibers. Despite their different shaped load-deflection curves, the flexural load carrying capacity of PP and PVA FRCCs was approximately same with the prismatic specimens (thickness/span = 0.31). According to center-point and two-point loading flexural test results, two-point loading condition seems more appropriate to visualize multiple cracking for PVA fiber reinforced thin members

The Relationship Between Exercise Habit and Quality of Life in Mild to Moderate Alzheimer's Disease Patients

Amaç: Yaşlılarda egzersiz, birçok fizyolojik yararına rağmen, işlevsellik ve duygusal boyutlardaki etkinliği tartışmalı olan bir araçtır. Bu çalışma ile hafif-orta evre Alzheimer hastalarında egzersiz alışkanlığı ile yaşam kalitesi arasındaki ilişkinin incelenmesi amaçlanmıştır. Gereç ve Yöntem: Çalışmaya, düzenli egzersiz alışkanlığı olan (ortalama yaş; 68,03±8,98 yıl) ve hiç egzersiz yapmayan (ortalama yaş; 69,22±8,25 yıl) toplam 73 yaşlı birey katıldı. Klinik muayeneleri sırasında hastaların sosyodemografik özellikleri kaydedildi ve Standardize Mini Mental Testleri yapıldı. Alzheimer Hastalığı Yaşam Kalitesi Ölçeği ile yaşam kalitesi değerlendirildi. Son 3 ay içerisinde yapılan egzersizlerin türü ve frekansı hasta yakınlarına soruldu. Bulgular: Egzersiz alışkanlığı olan ve egzersiz yapmayan gruplar, yaş, cinsiyet, kognitif düzey ve hastalık süresi açısından benzerdi (p>0,05). Yaşam kalitesi toplam puanı, hasta ve yakını tarafından bildirilen yaşam kalitesi puanı, egzersiz alışkanlığı olan grupta daha yüksekti (p0,05). Sonuç: Düzenli egzersiz alışkanlığı olan hafif-orta evre Alzheimer hastalarında yaşam kalitesi, egzersiz tipi ve frekansından bağımsız olarak egzersiz yapmayanlara göre daha iyidir. Bu hastalarda herhangi bir egzersizin düzenli bir alışkanlık haline getirilmesi önerilmektedir.Objective: Despite its many physiological benefits, exercise in the elderly is a tool whose functionality and emotional effectiveness are controversial. In this study, it was aimed to examine the relationship between exercise habit and quality of life in mild-to moderate Alzheimer’s disease. Material and Method: A total of 73 geriatric people with regular exercise habit (mean age; 68.03±8.98 year) and no exercise ( mean age; 69.22±8.25 year) participated in the study. Sociodemographic characteristics of the patients who had Standardized Mini Mental Tests during their clinical examinations were recorded. Quality of life was evaluated with the Alzheimer’s Disease Quality of Life Scale. The type and frequency of the exercises performed in the last 3 months were asked to the proxies of the patients. Results: Both groups with exercise habits and without exercise were similar in terms of age, gender, cognitive level, and duration of illness (p>0.05). Quality of life total score and quality of life reported by the patient and proxies were higher in the group with exercise habit (p 0.05). Conclusion: The quality of life in mild-to-moderate Alzheimer’s disease patients with regular exercise habit is better than those who do not exercise, regardless of exercise type and frequency. It is recommended that any exercise should be made a regular habit in these patients

Effect of Camera Resolution on the Determination of Mechanical and Multiple Crack Properties of Engineered Cementitious Composites via Digital Image Correlation

In this study, the effect of image resolution on the determination of mechanical parameters and multiple crack properties of Engineered Cementitious Composites (ECC) was investigated by digital image correlation (DIC). For this purpose, low and high resolution images were captured during the tensile loading of ECC by using two cameras simultaneously. DIC analyzes were performed on the images and results were compared both within themselves and with the traditional method. Mechanical parameters have been successfully calculated with DIC analysis and consistent values obtained with traditional methodology. However, high resolution images were found to be more effective for detecting pattern properties than low resolution images. It resulted in low strain error when using high resolution images compared to low resolution images in DIC analysis. Finally, when the high resolution images were used in DIC analysis as opposed to the low resolution images, both the detected number of cracks and calculated crack widths were obtained accurately. This situation was proven by local strain maps provided by DIC

Physiotherapy and Rehabilitation Approaches in Earthquake-Related Thoracic Traumas

İnsan yaşamını etkileyen en önemli doğal afetlerden olan depremlere bağlı toraks travmaları yaygın olarak görülmektedir. Toraks travmaları farklı şekillerde ortaya çıkmakla birlikte sıklıkla ortaya çıkan kosta kırıklarına pulmoner kontüzyon, hemopnömotoraks gibi durumlar eşlik edebilir. Bununla birlikte bozulan solunum mekanikleri ve ağrı, atelektazi ve pnömoni gibi ciddi komplikasyonlar doğurabilmektedir. Fizyoterapistler oluşabilecek muhtemel engellerini önlemek ve azaltmak için depremzede bireylere yönelik çalışan sağlık ekibi içerisinde yer almakta, toraks travması gibi akut hasta yönetiminde önemli rol üstlenmektedir. Toraks travması sonrası fizyoterapi yaklaşımları arasında torakal ekspansiyon egzersizleri ve havayolu temizleme teknikleri gibi solunumsal müdahaleler, kas iskelet sistemine yönelik egzersiz ve mobilizasyon uygulamaları ile ağrı azaltma stratejileri yer almaktadır. Toraks travmaları sonrası fizyoterapi yaklaşımları mortalite ve pnömoni oranlarının azaltılması ve daha kısa süreli hastane yatışı gibi klinik sonuçlar ile ilişkilidir

COVID-19 Disease and Pulmonary Physiotherapy

Aralık 2019’da, Çin’in Wuhan kentinde ortaya çıkan ve Dünya Sağlık Örgütü’nün pandemi olarak ilan ettiği COVID-19, hastaların temel olarak respiratuar, kardiyovasküler, nörolojik ve kas-iskelet sistemlerini etkilemektedir. Vakaların %15’i şiddetli, %5’i ise ventilasyon ve yaşam desteği gerektiren çok şiddetli klinik tablo ile izlenmektedir. COVID-19 hastaları, bu etkiler sebebiyle hastalığın stabil olduğu erken dönemden itibaren pulmoner rehabilitasyona ihtiyaç duymaktadır. Solunum fizyoterapisi, pulmoner rehabilitasyonun önemli komponentlerinden biridir. Bu derlemede güncel literatür eşliğinde, COVID-19 hastalarının hastane süreci ve taburculuklarında uygulanabilecek solunum fizyoterapi yöntemleri ve uygulamalar sırasında dikkat edilmesi gereken noktalar ele alınmıştır. COVID-19, which was appeared in Wuhan, China in December 2019 and declared by the World Health Organization a pandemic, affects patients’ respiratory, cardiovascular, neurological, and musculoskeletal systems. 15% of the cases are severe and 5% are followed by a very severe clinical condition that requires ventilation and life support. COVID-19 patients need pulmonary rehabilitation from the early stage on when the disease is stable due to these negative effects. Respiratory physiotherapy is one of the important components of pulmonary rehabilitation. In this review, respiratory physiotherapy methods which can be applied to patients during the treatment inhospital and after the discharge, and points to be considered in the application of these methods are discussed

Strength and durability of composite concretes using municipal wastes

The influence of different types of polyethylene (PE) substitutions as partial aggregate replacement of micro-steel fiber reinforced self-consolidating concrete (SCC) incorporating incinerator fly ash was investigated. The study focuses on the workability and hardened properties including mechanical, permeability properties, sulfate resistance and microstructure. Regardless of the polyethylene type, PE substitutions slightly decreased the compressive and flexural strength of SSC initially, however, the difference was compensated at later ages. SEM analysis of the interfacial transition zone showed that there was chemical interaction between PE and the matrix. Although PE substitutions increased the permeable porosity and sorptivity, it significantly improved the sulfate resistance of SCC. The influence of PE shape and size on workability and strength was found to be more important than its type. When considering the disposal of PE wastes and saving embodied energy, consuming recycled PE as partial aggregate replacement was more advantageous over virgin PE aggregate replaced concrete

Effects of fibre hybridization on multiple cracking potential of cement-based composites under flexural loading

The effects of individual and combined additions of polypropylene (PP) and polyvinyl-alcohol (PVA) fibres (PP/PVA fibre ratios: 3/0%, 2/1%, 1.5/1.5%, 1/2% and 0/3%) on the flexural behaviour of cement-based composites have been investigated. For this purpose, matrices at different strength grades have been used. The binder composition of high strength matrix (MI) was solely cement and 50% of cement was replaced with fly ash to prepare a comparatively low strength matrix (Mil). Thirty prismatic samples are subjected to four-point flexural loading after 28 days of standard curing. The load mid-span deflection curves have been plotted and simultaneously cracking patterns of composites have been photographed at definite deflection values. First cracking and flexural strength, deflection and relative toughness values have been determined for all samples

Effects of fiber-matrix interaction on multiple cracking performance of polymeric fiber reinforced cementitious composites

The effects of polymeric fiber addition on the multiple cracking performance of composites have been investigated. For this purpose, cement-based matrices incorporating fly ash and a latex emulsion have been designed. Prismatic samples have been prepared and subjected to four-point bending load. The load-midpoint deflection curves and crack patterns have been determined. Meanwhile, flexural strength and relative toughness values have been calculated. Finally, the number of visible cracks formed throughout the testing period has been analyzed

Multiple cracking response of plasma treated polyethylene fiber reinforced cementitious composites under flexural loading

The effects of low frequency cold plasma treatments on the microstructure and chemistry of Polyethylene (PE) have been investigated. PE plates and fibers were exposed to plasmas of argon and oxygen gases. The surface wettabilities of plasma-treated plates were monitored. Possible physical changes on fiber surfaces were observed by a scanning electron microscope (SEM) at micrometer scale and by an atomic force microscope (AFM) at nanometer scale after this process. The effects of plasma treatment on surface chemistry of PE fibers have been analyzed by using an X-ray photoemission spectroscope (XPS). The fibers modified by plasma treatments were used in prismatic cementitious composites. The flexural performance of samples were characterized at two different ages (28 days and 8 months). Results showed that plasma treatment caused significant modifications on fibers' surface structure and composites' performance. Proper plasma treatment conditions significantly leads to improvement of multiple cracking behavior of fiber reinforced composites. (C) 2011 Elsevier Ltd. All rights reserved