الإطار النظري لنظام الدفع-الاسترداد في مجال نفايات التغليف

The deposit-refund-system combines a tax between producer and consumer that is refunded if the packaging is used for recycling. This system can be used for plastic, cardboard and aluminum packaging, in addition to batteries, and electronic machinery. The deposit-refund system is based on automatic distributors or sorting centers to return the paid deposit. It has several advantages such as the reduction of the quantities of waste put in landfills or landfill, and on the other hand the increase of recycled materials as well as the reduction of the costs of management of household wast

Transesterification of sunflower oil using heterogeneous catalyst derived from date seeds of South Algeria

Date Seeds (DS) were transformed into catalyst by calcining them at various temperatures. The produced catalyst was fully characterized by SEM, XRF, and BET analyses. The basicity of the catalyst was determined using CO2-TPD technique. The catalytic efficiency of the prepared catalyst was tested in the transesterification of sunflower oil with methanol. The effect of calcination temperature on the yield of Fatty Acid Methyl Ester (FAME) was investigated. In addition the transesterification process was optimised. In this study, the effect of FFA (Free Fatty Acid) on FAME yield was also investigated. The results show that the produced catalyst from date seeds is a good catalyst for biodiesel production reaction. The maximum biodiesel yield reached about 96.7% under the optimal conditions

Global and regional estimates for COPD prevalence: Systematic review and meta-analysis

Background The burden of chronic obstructive pulmonary disease (COPD) across many world regions is high. We aim to estimate COPD prevalence and number of disease cases for the years 1990 and 2010 across world regions based on the best available evidence in publicly accessible scientific databases. Methods We conducted a systematic search of Medline, EMBASE and Global Health for original, population–based studies providing spirometry– based prevalence rates of COPD across the world from January 1990 to December 2014. Random effects meta–analysis was conducted on extracted crude prevalence rates of COPD, with overall summaries of the meta–estimates (and confidence intervals) reported separately for World Health Organization (WHO) regions, the World Bank's income categories and settings (urban and rural). We developed a meta–regression epidemiological model that we used to estimate the prevalence of COPD in people aged 30 years or more. Findings Our search returned 37 472 publications. A total of 123 studies based on a spirometry–defined prevalence were retained for the review. From the meta–regression epidemiological model, we estimated about 227.3 million COPD cases in the year 1990 among people aged 30 years or more, corresponding to a global prevalence of 10.7% (95% confidence interval (CI) 7.3%–14.0%) in this age group. The number of COPD cases increased to 384 million in 2010, with a global prevalence of 11.7% (8.4%–15.0%). This increase of 68.9% was mainly driven by global demographic changes. Across WHO regions, the highest prevalence was estimated in the Americas (13.3% in 1990 and 15.2% in 2010), and the lowest in South East Asia (7.9% in 1990 and 9.7% in 2010). The percentage increase in COPD cases between 1990 and 2010 was the highest in the Eastern Mediterranean region (118.7%), followed by the African region (102.1%), while the European region recorded the lowest increase (22.5%). In 1990, we estimated about 120.9 million COPD cases among urban dwellers (prevalence of 13.2%) and 106.3 million cases among rural dwellers (prevalence of 8.8%). In 2010, there were more than 230 million COPD cases among urban dwellers (prevalence of 13.6%) and 153.7 million among rural dwellers (prevalence of 9.7%). The overall prevalence in men aged 30 years or more was 14.3% (95% CI 13.3%–15.3%) compared to 7.6% (95% CI 7.0%– 8.2%) in women. Conclusions Our findings suggest a high and growing prevalence of COPD, both globally and regionally. There is a paucity of studies in Africa, South East Asia and the Eastern Mediterranean region. There is a need for governments, policy makers and international organizations to consider strengthening collaborations to address COPD globall

Properties of lightweight concrete made with crushed natural pozzolana as coarse aggregate

This paper describes a laboratory‐based study examinig the use of natural pozzolana as an aggregate component in lightweight concrete (LWC). A range of conditioning variables, including cement and moisture content, storage period up to one year, was investigated. In order to explore these effects, a series of five concrete mixes using the same Portland cement was prepared. Three mixes (LWC1, LWC2, LWC3) were designed with cement content of 400 kg/m3 and three different W/C ratios leading to three different workability expressed with of a measured slumps of (3±1, 5±1 and 7±1) cm. Further two mixes (LWC4, LWC5) were also made with cement dosage of 300 and 350 kg/m3 and a constant workability with a slump of 3±1cm. The investigated properties included density, compressive strength, tensile strength and elastic modulus. The results were obtained for ages up to 365 days under different curing conditions (wet and dry). It is concluded that LWC with pozzolana, as coarse aggregate, has sufficient strength and adequate density to be accepted as structural lightweight concrete. Lengvojo betono, gaminto iš gamtinio pucolano ir naudojamo kaip stambusis užpildas, savybės Santrauka Aprašomi laboratoriniai tyrimai, kurie buvo atliekami siekiant nustatyti gamtinio pucolano naudojimo užpildu lengvajam betonui (LB) gaminti. Buvo tiriama daug kintamųjų, kaip antai cemento kiekis, drėgnumas, laikymo trukmė iki vienerių metų. Minėtų kintamųjų poveikiui nustatyti buvo pagaminti penki betono mišiniai, naudojant tą patį portlandcementį. Trys mišiniai LB1, LB2 ir LB3 buvo pagaminti iš cemento, kurio tūrio masė lygi 400 kg/m3, tačiau su trimis skirtingais V/C santykiais, lemiančiais betono technologiškumą, o kartu turinčiais skirtingą slankį, atitinkamai: 3 ± 1 cm, 5 ± 1 cm ir 7 ± 1 cm. Du likę mišiniai LB4 ir LB5 buvo pagaminti iš 300 kg/m3 ir 350 kg/m3 tūrio masės cemento, kurių technologiškumas ir slankumas toks pats – 3 ± 1 cm. Buvo tiriamos šios medžiagų savybės: tankis, gniuždomasis ir tempiamasis stipris, elastingumo modulis. Tyrimo rezultatai buvo gauti laikant medžiagas skirtingomis sąlygomis (sausoje ir drėgnoje aplinkoje) iki 365 dienų. Daroma išvada, jog lengvasis betonas, pagamintas naudojant pucolaną kaip stambųjį užpildą, turi pakankamą stiprumą ir tankį, kad būtų naudojamas konstrukcijoms betonuoti. First Published Online: 21 Oct 2010 Reikšminiai žodžiai: lengvasis betonas, lengvasis užpildas, pucolanas, mechanines savybes, gniuždomasis, tempiamasis stipris, gamtines medžiago

Characterization of an Algerian natural pozzolan for its use in eco-efficient cement

WOS:000367756300007International audienceThe paper presents the characterisation of an Algerian natural pozzolan (NP) intended to for use in cement-based materials. The experimental programme was based on different tests on paste and mortar. The pozzolanic activity was assessed by the means of lime consumption over time of mixtures of lime-pozzolan (75% NP and 25% Ca(OH)(2), water-binder ratio of 0.45). The degree of reactivity was assessed by observing the crystallographic changes (XRD) and lime constumption (TG) up to 1 year of hydration. The effect of NP on cement-based mixtures was based on the measurement of the water demand and setting time of pastes, and on the compressive strength of mortars, up to one year. The replacement rates of cement by pozzolan were 5, 10 and 15%. A superplasticizer was used (0, 1, 2 and 3% of the binder mass). A calculation of the carbon footprint was investigated in order to assess if the natural pozzolan could be considered as eco-efficient when used in replacement of the clinker. The results showed that NP had a medium pozzolanic reactivity and with a medium-low silica content. The use of NP usually led to a small increase in the water/binder ratio (up to 10%) to maintain constant workability. The setting time was also increased by around 20%. Nevertheless, strength tests showed that the pozzolan had sufficient activity to counteract the water demand, since long-term compressive strength of the binary system (cement + pozzolan) were higher than those of cement alone. The use of NP in replacement of clinker involves a reduction in CO2 emissions for transport up to 1800 km, which is compatible with sustainable development. The results are most promising from both a performance-based and an environmental point of view

Characterization of an Algerian natural pozzolan for its use in eco-efficient cement

WOS:000367756300007International audienceThe paper presents the characterisation of an Algerian natural pozzolan (NP) intended to for use in cement-based materials. The experimental programme was based on different tests on paste and mortar. The pozzolanic activity was assessed by the means of lime consumption over time of mixtures of lime-pozzolan (75% NP and 25% Ca(OH)(2), water-binder ratio of 0.45). The degree of reactivity was assessed by observing the crystallographic changes (XRD) and lime constumption (TG) up to 1 year of hydration. The effect of NP on cement-based mixtures was based on the measurement of the water demand and setting time of pastes, and on the compressive strength of mortars, up to one year. The replacement rates of cement by pozzolan were 5, 10 and 15%. A superplasticizer was used (0, 1, 2 and 3% of the binder mass). A calculation of the carbon footprint was investigated in order to assess if the natural pozzolan could be considered as eco-efficient when used in replacement of the clinker. The results showed that NP had a medium pozzolanic reactivity and with a medium-low silica content. The use of NP usually led to a small increase in the water/binder ratio (up to 10%) to maintain constant workability. The setting time was also increased by around 20%. Nevertheless, strength tests showed that the pozzolan had sufficient activity to counteract the water demand, since long-term compressive strength of the binary system (cement + pozzolan) were higher than those of cement alone. The use of NP in replacement of clinker involves a reduction in CO2 emissions for transport up to 1800 km, which is compatible with sustainable development. The results are most promising from both a performance-based and an environmental point of view

Bâtiments construits en adobe salin, durabilité centenaire et confort thermique dans un climat désertique

International audienceL’adobe est un matériau à inertie thermique importante, mais il se caractérise par unefaible résistance mécanique soit en compression ou en flexion. L’utilisation d’adobesalin confectionné à l'aide d'un sable salin dans les bâtiments traditionnels dans la zonesaharienne de l’Algérie présente une meilleure protection de ces bâtiments vis-à-vis desintempéries et offre une bonne isolation thermique au bâtiment. Nos mesuresexpérimentales effectuées sur les bâtiments traditionnels existants montrent quel’ambiance intérieure est tempérée et la température intérieure est quasiconstante variant entre 31 et 33 °C, alors que celle de l’extérieur dépasse les 50 °C,marquant ainsi un écart journalier d'environ 17 °C. Cela influe positivement sur leconfort thermique des habitants. Ce matériau apporte, par conséquent, une solutionidéale aux habitants du Sahara, et apporte du confort thermique à l’intérieur dubâtiment sans recours à la climatisation électrique

الإطار النظري لنظام الدفع-الاسترداد في مجال نفايات التغليف

The deposit-refund-system combines a tax between producer and consumer that is refunded if the packaging is used for recycling. This system can be used for plastic, cardboard and aluminum packaging, in addition to batteries, and electronic machinery. The deposit-refund system is based on automatic distributors or sorting centers to return the paid deposit. It has several advantages such as the reduction of the quantities of waste put in landfills or landfill, and on the other hand the increase of recycled materials as well as the reduction of the costs of management of household wast

Investigation of the engineering properties of environmentally-friendly self-compacting lightweight mortar containing olive kernel shells as aggregate

International audienceThe present study investigates the possibility of developing a self-compacting lightweight mortar (SCLM) using an agricultural by-product, namely the Crushed Olive Kernel (COK) Shell. The valorization of these co-products can certainly make it possible to use them as a substitute for natural aggregates and thus create additional economic, social and environmental value; it also allows a better handling and management of these co-products.COK shells are used in this study as partial replacement of sand, at different rates, i.e. 0, 25, 50, 75 and 100%. The influence of aggregates content on the physical, mechanical and thermal characteristics of the new materials is studied, analyzed and evaluated.Since these new materials have lower thermal conductivities than that of reference mortar, they can successfully be used as substitutes for natural sand in building materials.The results obtained support the possibility of manufacturing SCLM with a 28-day compressive strength of 9.58 MPa at a 100% COK substitution rate and a thermal conductivity of 0.326 W/m.K. The flexural strength, ultrasonic pulse velocity (UPV) and modulus of elasticity (Ed) were reduced by 61%, 51% and 85%, respectively as compared to those of the reference mortar (SCMO). It is also apparent from this study that COKs are light aggregates that allow formulating light self-compacting mortars with a density between 1400 and 1900 kg/m3

Bâtiments construits en adobe salin, durabilité centenaire et confort thermique dans un climat désertique

International audienceL’adobe est un matériau à inertie thermique importante, mais il se caractérise par unefaible résistance mécanique soit en compression ou en flexion. L’utilisation d’adobesalin confectionné à l'aide d'un sable salin dans les bâtiments traditionnels dans la zonesaharienne de l’Algérie présente une meilleure protection de ces bâtiments vis-à-vis desintempéries et offre une bonne isolation thermique au bâtiment. Nos mesuresexpérimentales effectuées sur les bâtiments traditionnels existants montrent quel’ambiance intérieure est tempérée et la température intérieure est quasiconstante variant entre 31 et 33 °C, alors que celle de l’extérieur dépasse les 50 °C,marquant ainsi un écart journalier d'environ 17 °C. Cela influe positivement sur leconfort thermique des habitants. Ce matériau apporte, par conséquent, une solutionidéale aux habitants du Sahara, et apporte du confort thermique à l’intérieur dubâtiment sans recours à la climatisation électrique