Some factors affecting the efficiency of potato production, under Al–Ghab plain conditions, Syrian Arab Republic

ArticleData were collected by a field survey of 300 farmers from Al–Ghab region (Syria) during 2014–2015. The non–parametric Data Envelopment was used in analyzing the Technical efficiency. The relationship between farm size and production efficiency was considered. Technical efficiency amounted about 53% and most of farms are operating at low level of technical efficiency. The relationship between farm size and productivity efficiency is Non– linear, it decreases from small to medium farm size and then increases as the size increase. Large farms have the higher net farm income per thousand square metersand are the most efficient technically followed by small and medium farm size. To disclose that factors causing the technical efficiency, Two–limit Tobit Regression Model was used. The calculated results showed that, Household Size, Occupation, Farm Size, Experience in Farming, Seed Type and Membership are factors that cause the technical inefficiency potato farming at Al–Ghab region. Therefore, the Syrian Planning Board and Decision Makers should take this results into account when they draw their plans to improve farmer's skills by allocating more investment in farm research and extension programmers

Characterisation of mechanical and thermal properties in flax fabric reinforced geopolymer composites

This paper presents the mechanical and thermal properties of flax fabric reinforced fly ash based geopolymer composites. Geopolymer composites reinforced with 2.4, 3.0 and 4.1 wt% woven flax fabric in various layers were fabricated using a hand lay-up technique and tested for mechanical properties such as flexural strength, flexural modulus, compressive strength, hardness, and fracture toughness. All mechanical properties were improved by increasing the flax fibre contents, and showed superior mechanical properties over a pure geopolymer matrix. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) studies were carried out to evaluate the composition and fracture surfaces of geopolymer and geopolymer/flax composites. The thermal behaviour of composites was studied by thermogravimetric analysis (TGA) and the results showed significant degradation of flax fibres at 300 °C

Mechanical properties of cotton fabric reinforced geopolymer composites at 200-1000 °C

Geopolymer composites containing woven cotton fabric (0–8.3 wt%) were fabricated using the hand lay-up technique, and were exposed to elevated temperatures of 200 °C, 400 °C, 600 °C, 800 °C and 1000 °C. With an increase in temperature, the geopolymer composites exhibited a reduction in compressive strength, flexural strength and fracture toughness. When heated above 600 °C, the composites exhibited a significant reduction in mechanical properties. They also exhibited brittle behavior due to severe degradation of cotton fibres and the creation of additional porosity in the composites. Microstructural images verified the existence of voids and small channels in the composites due to fibre degradation

Identifying the research, advocacy, policy and implementation needs for the prevention and management of respiratory syncytial virus lower respiratory tract infection in low- and middle-income countries

Introduction: The high burden of respiratory syncytial virus (RSV) infection in young children disproportionately occurs in low- and middle-income countries (LMICs). The PROUD (Preventing RespiratOry syncytial virUs in unDerdeveloped countries) Taskforce of 24 RSV worldwide experts assessed key needs for RSV prevention in LMICs, including vaccine and newer preventive measures. Methods: A global, survey-based study was undertaken in 2021. An online questionnaire was developed following three meetings of the Taskforce panellists wherein factors related to RSV infection, its prevention and management were identified using iterative questioning. Each factor was scored, by non-panellists interested in RSV, on a scale of zero (very-low-relevance) to 100 (very-high-relevance) within two scenarios: (1) Current and (2) Future expectations for RSV management. Results: Ninety questionnaires were completed: 70 by respondents (71.4% physicians; 27.1% researchers/scientists) from 16 LMICs and 20 from nine high-income (HI) countries (90.0% physicians; 5.0% researchers/scientists), as a reference group. Within LMICs, RSV awareness was perceived to be low, and management was not prioritised. Of the 100 factors scored, those related to improved diagnosis particularly access to affordable point-of-care diagnostics, disease burden data generation, clinical and general education, prompt access to new interventions, and engagement with policymakers/payers were identified of paramount importance. There was a strong need for clinical education and local data generation in the lowest economies, whereas upper-middle income countries were more closely aligned with HI countries in terms of current RSV service provision. Conclusion: Seven key actions for improving RSV prevention and management in LMICs are proposed

Characterizing the modal responses of a composite soil nail under axial excitation = Caract\ue9risation de la r\ue9ponse modale d'un clou de sol composite soumis \ue0 une excitation axiale

This paper characterizes the waves induced in a grouted soil nail from axial excitations in an attempt to develop a non-destructive field procedure for determining the length of in-situ soil nails. The study comprised experimental tests in which a 3.66-m long grouted laboratory soil nail was built and tested and numerical analyses in which a finite element model (FEM) of the nail was developed and calibrated. The FEM clarified the experimental responses of the nail by providing wave velocities and mode shapes for natural frequencies below 5 kHz, which described the actual dynamic behaviour of the soil nail. The results showed that axial excitations of the composite soil nail induced modes, which displayed both shear and longitudinal behaviour. Wave velocities below 3000 m/s suggested shear wave modes of energy transport whereas the nearly uniform axial displacements within the cross sections of the nail were more in keeping with longitudinal modes of behaviour.Cette publication caract\ue9rise les ondes induites dans un clou de sol soumis \ue0 des excitations axiales afin de d\ue9velopper une proc\ue9dure de terrain non destructive pour d\ue9terminer la longueur des clous de sol. L'\ue9tude comportait : (i) des essais exp\ue9rimentaux dans lesquels un clou de sol d'une longueur de 3,66 m a \ue9t\ue9 fabriqu\ue9 et test\ue9 en laboratoire, et (ii) des analyses num\ue9riques dans lesquelles un mod\ue8le d'\ue9l\ue9ments finis du clou a \ue9t\ue9 d\ue9velopp\ue9 et calibr\ue9. La mod\ue9lisation par \ue9l\ue9ments finis a permis de clarifier la r\ue9ponse exp\ue9rimentale du clou en fournissant les vitesses de propagation des ondes et les formes modales pour les fr\ue9quences naturelles inf\ue9rieures \ue0 5 kHz, qui d\ue9crivaient le comportement dynamique actuel du clou de sol. Les r\ue9sultats ont montr\ue9 que les excitations axiales du clou de sol induisaient des modes avec des comportements de cisaillement et longitudinal. Les vitesses de propagation d'ondes inf\ue9rieures \ue0 3000 m/s ont sugg\ue9r\ue9 la pr\ue9sence de modes de cisaillement de transport d'\ue9nergie tandis que les d\ue9placements axiaux quasi-uniformes dans la section transversale du clou \ue9taient plus reli\ue9s aux modes longitudinaux de comportement.Peer reviewed: YesNRC publication: Ye

Characterizing the modal response of a composite soil nail under axial excitation

This paper characterizes the waves induced in a grouted soil nail from axial excitations in an attempt to develop a non-destructive field procedure for determining the length of in-situ soil nails. The study comprised experimental tests in which a 3.66-m long grouted laboratory soil nail was built and tested and numerical analyses in which a finite element model (FEM) of the nail was devel-oped and calibrated. The FEM clarified the experimental responses of the nail by providing wave velocities and mode shapes for natural frequencies below 5 kHz, which described the actual dynamic behaviour of the soil nail. The results showed that axial excita-tions of the composite soil nail induced modes, which displayed both shear and longitudinal behaviour. Wave velocities below 3000m/s suggested shear wave modes of energy transport whereas the nearly uniform axial displacements within the cross sections of the nail were more in keeping with longitudinal modes of behaviour.Cette publication caract\ue9rise les ondes induites dans un clou de sol soumis \ue0 des excitations axiales afin de d\ue9velopper uneproc\ue9dure de terrain non destructive pour d\ue9terminer la longueur des clous de sol. L'\ue9tude comportait : (i) des essais exp\ue9rimentaux dans lesquels un clou de sol d'une longueur de 3,66 m a \ue9t\ue9 fabriqu\ue9 et test\ue9 en laboratoire, et (ii) des analyses num\ue9riques dans les-quelles un mod\ue8le d'\ue9l\ue9ments finis du clou a \ue9t\ue9 d\ue9velopp\ue9 et calibr\ue9. La mod\ue9lisation par \ue9l\ue9ments finis a permis de clarifier lar\ue9ponse exp\ue9rimentale du clou en fournissant les vitesses de propagation des ondes et les formes modales pour les fr\ue9quences naturelles inf\ue9rieures \ue0 5 kHz, qui d\ue9crivaient le comportement dynamique actuel du clou de sol. Les r\ue9sultats ont montr\ue9 que les ex-citations axiales du clou de sol induisaient des modes avec des comportements de cisaillement et longitudinal. Les vitesses de propa-gation d'ondes inf\ue9rieures \ue0 3000 m/s ont sugg\ue9r\ue9 la pr\ue9sence de modes de cisaillement de transport d'\ue9nergie tandis que les d\ue9-placements axiaux quasi-uniformes dans la section transversale du clou \ue9taient plus reli\ue9s aux modes longitudinaux de comportement.Peer reviewed: YesNRC publication: Ye

Condition assessment of structural components using non-destructive techniques

Condition assessment of components is an important aspect for determining repair strategies of ageing structural systems and for ascertaining the durability of the repairs once they are effected. Two projects have been undertaken by the ?Concrete Materials and Structural Technologies Group? at the Institute for Research in Construction of the National Research Council Canada for studying both aspects of repairs. The first project is investigating the effectiveness of a sonic wave technique in accurately determining the in-situ length of newly installed soil nails. Once soil nails are inserted into the ground, their length can only be readily verified by destructively removing them. This project examines the efficacy of using the impulse-response technique to ascertain the length of grouted and ungrouted soil nails containing one or more coupled sections of steel bars. The second project is studying the effect of a fibre-reinforced polymer (FRP) laminate on the internal conditions of a steel reinforced concrete column. Two adjacent columns, one wrapped with a FRP laminate and the second left in its existing condition have been monitored over a period of many years. The monitoring comprises annual non-destructive sonic and electro-chemical surveys and continuous on-site recording of relative humidities and temperatures. The objective of the study is to determine whether the laminate affects the internal electro-chemical environment within the wrapped column so as to reduce the durability of the primary steel reinforcement. This paper gives a brief overview of the two projects and summarises what has been learned to date.L'\ue9valuation de l'\ue9tat des membrures est un aspect important de la d\ue9termination des strat\ue9gies de r\ue9paration de charpentes vieillissantes et de la v\ue9rification de la durabilit\ue9 des r\ue9parations apr\ue8s leur ex\ue9cution. Le \uab groupe sur les constituants du b\ue9ton et les techniques des structures \ubb de l'Institut de recherche en construction du Conseil national de recherches du Canada a entrepris deux projets dans le but d'\ue9tudier les deux aspects des r\ue9parations. Le premier projet consiste \ue0 \ue9tudier l'efficacit\ue9 d'une technique \ue0 ondes sonores relativement \ue0 la d\ue9termination avec pr\ue9cision de la longueur in situ de clous nouvellement pos\ue9s dans le sol. Une fois les clous enfonc\ue9s dans le sol, la seule fa\ue7on d'en v\ue9rifier facilement la longueur consiste \ue0 les enlever de fa\ue7on destructive. Le projet examine l'efficacit\ue9 de l'utilisation de la technique de la r\ue9ponse impulsionnelle pour v\ue9rifier la longueur de clous recouverts de coulis ou non et contenant un ou plusieurs tron\ue7ons assembl\ue9s de barres d'acier. Le second projet consiste \ue0 \ue9tudier l'effet d'un stratifi\ue9 en polym\ue8re renforc\ue9 de fibres (FRP) sur les conditions internes d'un poteau en b\ue9ton arm\ue9. Deux poteaux adjacents, dont l'un \ue9tait recouvert d'un stratifi\ue9 en polym\ue8re renforc\ue9 de fibres et le second, laiss\ue9 dans l'\ue9tat dans lequel il \ue9tait, ont \ue9t\ue9 contr\uf4l\ue9s pendant de nombreuses ann\ue9es. Le contr\uf4le comprenait des relev\ue9s soniques ou \ue9lectrochimiques non destructifs et l'enregistrement continu sur place de l'humidit\ue9 relative et de la temp\ue9rature. L'objectif de l'\ue9tude consiste \ue0 d\ue9terminer si le stratifi\ue9 influe sur l'environnement \ue9lectrochimique interne de la colonne recouverte et r\ue9duit la durabilit\ue9 de l'armature d'acier principale. Le pr\ue9sent document donne un bref aper\ue7u des deux projets et r\ue9sume ce qu'on a appris jusqu'\ue0 maintenant.Peer reviewed: YesNRC publication: Ye

Development of a non-destructive procedure for estimating the length of in-situ soil nails

Soil nails are used to stabilise soil embankments in the same way that rock anchors are placed to stabilise cuts into rock layers. Because of the large number of soil nails, which are installed every year in many parts of the world, particularly the Far East, a rapid and reliable method is desired to check the in-situ length of the nails. The industry tried to adopt the non-destructive sonic technique that measures the length of in-ground piles (ASTM D5882-00, Standard Test Method for Low Strain Integrity Testing of Piles) but the system showed severe limitations when it was applied to soil nails. A field procedure, which would reasonably estimate the lengths of installed nails, was therefore sought. This paper will present the difficulties encountered in trying to develop a practical test procedure using sonic wave techniques, the results of tests completed to date and the prospects for a successful outcome.Les clous de sol permettent de stabiliser les remblais en terre de la m\ueame mani\ue8re que les ancres de roche permettent de stabiliser plusieurs couches de roche. \uc9tant donn\ue9 qu'on installe un grand nombre de ces clous dans le sol chaque ann\ue9e aux quatre coins du globe et notamment en Extr\ueame-Orient, on a besoin d'une m\ue9thode rapide et fiable afin de pouvoir en v\ue9rifier la longueur sur le terrain. L'industrie a tent\ue9 d'adopter une technique acoustique non destructive qui mesure la longueur des pieux fich\ue9s dans le sol (ASTM D5882-00, Standard Test Method for Low Strain Testing of Piles) mais cette technique s'est av\ue9r\ue9e tr\ue8s limit\ue9e dans le cas des clous de sol. On a donc cherch\ue9 une proc\ue9dure sur le terrain qui permettrait d'estimer convenablement la longueur des clous d\ue9j\ue0 install\ue9s. Cet article pr\ue9sente les difficult\ue9s rencontr\ue9es en essayant d'\ue9laborer une proc\ue9dure d'essais pratique utilisant la technique des ondes acoustiques, les r\ue9sultats des essais effectu\ue9s \ue0 ce jour et les perspectives de succ\ue8s.Peer reviewed: YesNRC publication: Ye

Effect of train-induced vibrations on houses - a case study

Train-induced vibrations of houses and mobile homes in Kamloops, British Columbia, were investigated to determine whether the vibrations could have resulted in damage to residences near the tracks. A detailed investigation showed that building resonance could result in architectural damage up to 250 m from the tracks and that vibration-induced settlement could occur for certain mobile home foundations located on loose wet fill. The criterion for possible architectural damage to stucco and brittle interior finishes was taken as 5 mm/s peak velocity, measured at the ceiling level of the one-storey houses. As a result of this study, general recommendations are presented regarding the methods employed in investigating similar train vibration problems.On a \ue9tudi\ue9 l'effet des vibrations produites par les trains sur des maisons et des maisons mobiles de Kamloops, en Colombie-Britannique, afin de d\ue9terminer si ces vibrations auraient pu causer des dommages aux habitations situ\ue9es pr\ue8s des voies. Une investigation d\ue9taill\ue9e a r\ue9v\ue9l\ue9 que la r\ue9sonance des b\ue2timents pouvait provoquer des dommages architecturaux jusqu'\ue0 250 m des voies et qu'un tassement d\ufb aux vibrations pouvait se produire dans le cas de certaines fondations de maisons mobiles reposant sur des remblais humides meubles. Le crit\ue8re de dommages architecturaux possibles au stuc et aux rev\ueatements int\ue9rieurs fragiles a \ue9t\ue9 fix\ue9 \ue0 la vitesse maximale de 5 mm/s, mesur\ue9e au niveau duplafond des maisons d'un \ue9tage. Sur la base de cette investigation, on pr\ue9sente des recommandations g\ue9n\ue9rales concernant les m\ue9thodes employ\ue9es pour \ue9tudier les probl\ue8mes semblables de vibrations produites par le passage des trains.Peer reviewed: YesNRC publication: Ye