scholarly journals Biopolymer-Waste Fiber Reinforcement for Earthen Materials: Capillary, Mechanical, Impact, and Abrasion Performance

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1819
Author(s):  
Héctor Gonzalez-Calderon ◽  
Gerardo Araya-Letelier ◽  
Sabine Kunze ◽  
Claudia Burbano-Garcia ◽  
Úrsula Reidel ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Fiber Reinforcement ◽  
Impact Performance ◽  
Mechanical Impact ◽  
Chicken Feathers ◽  
Earthen Construction ◽  
The Impact ◽  
Positive Effect ◽  
By Products ◽  
Significant Increment

The poultry industry, highly prevalent worldwide, generates approximately 7.7 × 106 metric tons of chicken feathers (CFs), which become a major environmental challenge due to their disposal when considered waste or due to their energy transformation consumption when considered by-products. CFs are mainly composed of keratin (approximately 90%), which is one of the most important biopolymers whose inherent characteristics make CFs suitable as biopolymer fibers (BPFs). This paper first assesses the morphological and chemical characteristics of these BPFs, through scanning electron microscopy and energy dispersive X-ray spectroscopy, and then evaluates the waste valorization of these BPFs as a sustainable alternative for fiber-reinforcement of earthen mixes intended for earthen construction, such as adobe masonry, rammed earth, and earthen plasters. In particular, four earthen mixes with increasing doses of BPFs (i.e., 0%, 0.25%, 0.5%, and 1% of BPFs by weight of soil) were developed to evaluate the impact of BPF-reinforcement on the capillary, mechanical, impact, and abrasion performance of these earthen mixes. The addition of BPFs did not significantly affect the mechanical performance of earthen mixes, and their incorporation had a statistically significant positive effect on the impact performance and abrasion resistance of earthen mixes as the BPF dose increased. On the other hand, the addition of BPFs increased the capillary water absorption rate, possibly due to a detected increment in porosity, which might reduce the durability of water-exposed BPF-reinforced earthen mixes, but a statistically significant increment only occurred when the highest BPF dose was used (1%).

Fibre-Cement Paste Transition Zone

1994 ◽  
Vol 370 ◽  
Author(s):  
Vahan Agopyan ◽  
Holmer Savastano
Keyword(s):  
Transition Zone ◽  
Mechanical Performance ◽  
Mechanical Tests ◽  
Polypropylene Fibres ◽  
Impact Performance ◽  
The Matrix ◽  
Vegetable Fibre ◽  
Electron Image ◽  
Backscattered Electron ◽  
The Impact

AbstractThe characteristics of fibres and paste of ordinary Portland cement transition zone are analysed and correlated to the mechanical properties of the produced composites. The water-cement ratio of the matrix varies from 0.30 to 0.46 and the age of the specimens varies from 7 to 180 days. Composites of vegetable fibres (coir, sisal and malva) are compared with those of chrysotile asbestos and polypropylene fibres. The analysis is made by backscattered electron image (BSEI) and energy dispersive spectroscopy (EDS). Mechanical tests evaluate the composite tensile strength and ductility.Mainly for vegetable fibre composites the transition zone is porous, cracked and rich in calcium hydroxide macrocrystals. These results are directly associated with the fibre-matrix bonding and with the composite mechanical performance. Further studies considering the impact performance of the composites compare the porosity of the transition zone with the toughness of the composites.

scholarly journals Impact and Post-Impact Performance of Sandwich Wall Boards with GFRP Face Sheets and a Web-Foam Core: The Effects of Impact Location

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1714 ◽  
Author(s):  
Yiwei Xia ◽  
Xiaoping Li ◽  
Yu Peng ◽  
Mianheng Lai ◽  
Lu Wang
Keyword(s):  
Mechanical Performance ◽  
Loading Capacity ◽  
Foam Core ◽  
Impact Performance ◽  
Impact Location ◽  
Post Impact ◽  
Sandwich Wall ◽  
Ultimate Loading Capacity ◽  
The Impact ◽  
Ultimate Loading

In recent years, load-bearing exterior sandwich wall boards have been adopted in civil engineering. The exterior walls of structures are often exposed to low velocity impacts such as stones, tools, and windborne debris, etc. The ultimate loading capacity, deformation, and ductility of sandwich walls are weakened by impact loads. In this study, the sandwich wall boards consisted of glass fiber reinforced plastic (GFRP) face sheets and a web-foam core. The core of wall boards was not the isotropic material. There was no doubt that the mechanical performance was seriously influenced by the impact locations. Therefore, it is necessary to carry out an investigation on the impact and post-impact performance of exterior wall boards. A comprehensive testing program was conducted to evaluate the effects of impact locations and impact energies on the maximum contact load, deflection, and contact time. Meanwhile, the compression after impact (CAI) performance of wall boards were also studied. The results indicated that the impact location significantly affects the performance of wall boards. Compared with an un-damaged wall board, the residual ultimate loading capacity of damaged wall boards reduced seriously, which were not larger than 50% of the designed ultimate loading capacity.

scholarly journals Increasing the Impact Toughness of Cellulose Fiber Reinforced Polypropylene Composites—Influence of Different Impact Modifiers and Production Scales

2019 ◽  
Vol 3 (3) ◽  
pp. 82
Author(s):  
Matthias Mihalic ◽  
Lukas Sobczak ◽  
Claudia Pretschuh ◽  
Christoph Unterweger
Keyword(s):  
Impact Strength ◽  
Mechanical Performance ◽  
Cellulose Fiber ◽  
Fiber Reinforced ◽  
Impact Performance ◽  
Polypropylene Composites ◽  
Cellulose Composites ◽  
Composite Production ◽  
The Impact ◽  
Cellulose Composite

While cellulose fiber reinforced polypropylene (PP) composites typically offer good stiffness and strength in combination with ecological benefits and a high potential for lightweight construction, they often require measures taken to improve their impact performance. In this work, the influence of different types of impact modifier on the mechanical performance of a PP–cellulose composite was systematically investigated, with a particular focus on the improvement of the notched impact strength and the accompanying loss of stiffness. Among the tested impact modifiers, ethylene-octene copolymers appeared to be the most suitable class to achieve a good overall performance. A high modifier viscosity increased its potential to improve the notched impact strength of the composite. Additionally, composite production on a larger scale improved the impact performance without significantly affecting the tensile properties. Several composites from this study surpassed the overall mechanical performance of a benchmark commercial PP–cellulose composite. While the impact strength of commercial high-impact PP–talc composites could not be reached, the considerably lower density of the PP–cellulose composites is worth mentioning.

Hydrogen Cyanide Polymers from the Impact of Comet P/Shoemaker-Levy 9 on Jupiter

1997 ◽  
Vol 161 ◽  
pp. 179-187
Author(s):  
Clifford N. Matthews ◽  
Rose A. Pesce-Rodriguez ◽  
Shirley A. Liebman
Keyword(s):  
Amino Acids ◽  
Solar System ◽  
Hydrogen Cyanide ◽  
Nitrogen Heterocycles ◽  
Laboratory Studies ◽  
Heterogeneous Solids ◽  
The Many ◽  
Comet Halley ◽  
The Impact ◽  
By Products

AbstractHydrogen cyanide polymers – heterogeneous solids ranging in color from yellow to orange to brown to black – may be among the organic macromolecules most readily formed within the Solar System. The non-volatile black crust of comet Halley, for example, as well as the extensive orangebrown streaks in the atmosphere of Jupiter, might consist largely of such polymers synthesized from HCN formed by photolysis of methane and ammonia, the color observed depending on the concentration of HCN involved. Laboratory studies of these ubiquitous compounds point to the presence of polyamidine structures synthesized directly from hydrogen cyanide. These would be converted by water to polypeptides which can be further hydrolyzed to α-amino acids. Black polymers and multimers with conjugated ladder structures derived from HCN could also be formed and might well be the source of the many nitrogen heterocycles, adenine included, observed after pyrolysis. The dark brown color arising from the impacts of comet P/Shoemaker-Levy 9 on Jupiter might therefore be mainly caused by the presence of HCN polymers, whether originally present, deposited by the impactor or synthesized directly from HCN. Spectroscopic detection of these predicted macromolecules and their hydrolytic and pyrolytic by-products would strengthen significantly the hypothesis that cyanide polymerization is a preferred pathway for prebiotic and extraterrestrial chemistry.

Microstructural and Mechanical Behaviour Evaluation of Mg-Al-Zn Alloy Friction Stir Welded Joint

2020 ◽  
Vol 17 (3) ◽  
pp. 8150-8159
Author(s):  
Kulwant Singh ◽  
Gurbhinder Singh ◽  
Harmeet Singh
Keyword(s):  
Heat Treatment ◽  
Friction Stir Welding ◽  
Magnesium Alloys ◽  
Mechanical Performance ◽  
Fuel Efficiency ◽  
Research Work ◽  
Grain Structure ◽  
Tensile Fracture ◽  
Friction Stir ◽  
The Impact

The weight reduction concept is most effective to reduce the emissions of greenhouse gases from vehicles, which also improves fuel efficiency. Amongst lightweight materials, magnesium alloys are attractive to the automotive sector as a structural material. Welding feasibility of magnesium alloys acts as an influential role in its usage for lightweight prospects. Friction stir welding (FSW) is an appropriate technique as compared to other welding techniques to join magnesium alloys. Field of friction stir welding is emerging in the current scenario. The friction stir welding technique has been selected to weld AZ91 magnesium alloys in the current research work. The microstructure and mechanical characteristics of the produced FSW butt joints have been investigated. Further, the influence of post welding heat treatment (at 260 °C for 1 h) on these properties has also been examined. Post welding heat treatment (PWHT) resulted in the improvement of the grain structure of weld zones which affected the mechanical performance of the joints. After heat treatment, the tensile strength and elongation of the joint increased by 12.6 % and 31.9 % respectively. It is proven that after PWHT, the microhardness of the stir zone reduced and a comparatively smoothened microhardness profile of the FSW joint obtained. No considerable variation in the location of the tensile fracture was witnessed after PWHT. The results show that the impact toughness of the weld joints further decreases after post welding heat treatment.

Impact of Digitalization on Service Work in Knowledge-Intensive Business Services: An Empirical Study in Tax Consultancies

2019 ◽  
Vol 3 (4) ◽  
pp. 209-222
Author(s):  
Philipp K. Görs ◽  
Henning Hummert ◽  
Anne Traum ◽  
Friedemann W. Nerdinger
Keyword(s):  
Work Engagement ◽  
Service Work ◽  
Psychological Consequences ◽  
Business Services ◽  
Knowledge Intensive Business Services ◽  
Positive Effects ◽  
Knowledge Intensive ◽  
The Impact ◽  
Positive Effect ◽  
Special Case

Digitalization is a megatrend, but there is relatively little knowledge about its consequences for service work in general and specifically in knowledge-intensive business services (KIBS). We studied the impact of digitalization on psychological consequences for employees in tax consultancies as a special case of KIBS. We compare two tax consulting jobs with very different job demands, those of tax consultants (TCs) and assistant tax consultants (ATCs). The results show that the extent of digitalization at the workplace level for ATCs correlates significantly positively with their job satisfaction. For TCs, the same variable correlates positively with their work engagement. These positive effects of digitalization are mediated in the case of ATCs by the impact on important job characteristics. In the case of TCs, which already have very good working conditions, the impact is mediated by the positive effect on self-efficacy. Theoretical and practical consequences of these results are discussed.

Comparative study of the impact of two mechanical perforation densities on the behavior of a sandy soil

2012 ◽  
Vol 8 (1) ◽  
pp. 37-48
Author(s):  
S. Chehaibi ◽  
K. Abrougui ◽  
F. Haouala
Keyword(s):  
Soil Water ◽  
Sandy Soil ◽  
Water Infiltration ◽  
Cone Penetration ◽  
Initial State ◽  
Soil Water Infiltration ◽  
Good Improvement ◽  
The Impact ◽  
Positive Effect ◽  
Resistance To Penetration

The effects of mechanical perforation densities by extracting soil cores through an aerator Vertidrain with a working width of 1.6 m and equipped with hollow tines spaced of 65 mm, were studied on a sandy soil of a grassy sward in the Golf Course El Kantaoui in Sousse (Tunisia). The mechanical aeration was performed at two densities: 250 and 350 holes/m2. The cone penetration resistance and soil water infiltration were measured. These parameters were performed at initial state before aeration (E0) and then on the 10th, 20th and 30th day after aeration. These results showed that perforation density of 350 holes/m2 had a positive effect on the soil by reducing its cone resistance to penetration compared to the initial state (Rp = 14.8 daN/cm2). At 5 cm depth the decrease in resistance to penetration was 34% and 43% on the 10th and 20th day after aeration, respectively. However, on the 30th day after aeration the soil resistance to penetration tended to grow and its value compared to the initial state decreased only by 21 and 26%, respectively, at 5 and 15 cm of depth only by 10% and 9% with 250 holes/m2 density. The soil water infiltration made a good improvement after aeration compared to the initial state. This parameter increased from 4.8 cm/h to 8.3, 10.9 and 13.1 cm/h with 250 holes/m2 density and to 10, 12.9 and 14.8 cm/h with 350 holes/m2 density on the 10th, 20th and 30th day following the aeration.

ACOUSTIC PANEL CHICKEN FEATHER WASTE ENVIRONMENTALLY FRIENDLY

2020 ◽  
Author(s):  
Ansarullah ◽  
Ramli Rahim ◽  
Baharuddin Hamzah ◽  
Asniawaty Kusno ◽  
Muhammad Tayeb
Keyword(s):  
Animal Feed ◽  
Environmentally Friendly ◽  
Selling Price ◽  
Chicken Feather ◽  
Chicken Feathers ◽  
The Road ◽  
Feather Waste ◽  
Chicken Feather Waste ◽  
Almost All ◽  
The Impact

Chicken feathers are the result of waste from slaughterhouses and billions ofkilograms of waste produced by various kinds of poultry processing. This hal is a veryserious problem for the environment because it causes the impact of pollution. Hasmany utilization of chicken feather waste such as making komocen, accessories,upholstery materials, making brackets to the manufacture of animal feed but from theresults of this activity cannot reduce the production of chicken feathers that hiscontinuously increase every year. This is due to the fact that the selling price of chickenmeat has been reached by consumers with middle to upper economic levels. This caneasily be a chicken menu in almost all restaurants and restaurants to the food stalls onthe side of the road. An alternative way of utilizing chicken feathers is to makecomposite materials in the form of panels. Recent studies have shown that the pvacmaterial can be utilized as a mixing and adhesive material with mashed or groundfeathered composites to form a panel that can later be used as an acoustic material.The test results show that the absorption of chicken feathers and pvac glue into panelscan absorb sound well with an absorption coefficient of 0.59, light. This result is veryeconomical so it is worth to be recommended as an acoustic material. Apart from theresults of research methods carried out is one of the environmentally friendly activitiesin particular the handling of waste problems

THEORETICAL STUDY OF THE EFFECT OF GEOMETRICAL PARAMETERS AND LOCATION OF ROTOR IMPACT ELEMENTS OF AN IMPACT-CENTRIFUGAL GRINDER ON SPEED AND ANGLES OF CRUSHED PARTICLES FLIGHT

2020 ◽  
Keyword(s):  
Granulometric Composition ◽  
Theoretical Study ◽  
Process Efficiency ◽  
Geometrical Parameters ◽  
Grinding Process ◽  
Main Work ◽  
Impact Element ◽  
The Impact ◽  
Positive Effect ◽  
Efficiency Indicators

One of efficiency indicators of grain grinders is grain granulometric composition. The basis of mixed fodder is crushed grain, the particles of which must have a leveled granulometric composition for subsequent mixing and obtaining a high-quality feed mixture. In agricultural production, hammer crushers are widely used, in which the destruction of grain occurs due to the impact of a hinged hammer. The main disadvantage of these crushers is that not the entire surface of the hammers is involved in grinding, thus reduces grinding process efficiency. A slightly different principle of material destruction is laid down in the basis of the proposed design of the shock-centrifugal grinder. Main work is performed by flat impact elements located on the rotor, which serve to accelerate crushed particles with subsequent impact of them on the bump elements. An important step in the design of new constructions of shock-centrifugal grinders is to determine size and location of the impact elements on the rotor, without which the grinding process is not possible. In the calculation method presented, the dependencies for determining the velocities and angles of a single particle flight from the surface of a flat impact element for its specified dimensions are proposed. Two variants of an impact element location on the rotor are considered and analyzed: radial and at an angle in the direction of rotor rotation. As a result of research carried out, it is noted that in the case of inclined position of an impact element on the rotor an increase in flight speed and flight angles change in crushed particles, which gives the opportunity to have a positive effect on grinding process.

The Impact of Coping Strategies on Situational Coping in Daily Life: An Ecological Momentary Assessment Study with the mHealth application TrackYourStress (Preprint)

2020 ◽  
Author(s):  
Teresa O'Rourke ◽  
Carsten Vogel ◽  
Dennis John ◽  
Rüdiger Pryss ◽  
Johannes Schobel ◽  
...  
Keyword(s):  
Social Support ◽  
Coping Strategies ◽  
Daily Life ◽  
Stress Coping ◽  
Positive Thinking ◽  
Active Stress ◽  
Situational Coping ◽  
Ecological Momentary ◽  
The Impact ◽  
Positive Effect

BACKGROUND It is necessary to cope with situations in daily life to prevent stress-related health consequences. However, coping strategies might differ in their impact on dealing with stressful situations in daily life. Moreover, the effect of coping strategies on situational coping might differ between women and men. OBJECTIVE The aim of this study was to investigate the impact of coping strategies on situational coping in everyday life situations and to investigate gender differences. METHODS An ecological momentary assessment study with the mobile health app TrackYourStress (TYS) was conducted with 113 participants. Coping strategies were measured at baseline with the coping scales Positive Thinking, Active Stress Coping, Social Support, Support in Faith, and Alcohol and Cigarette Consumption of the Stress and Coping Inventory (SCI). Situational coping was assessed by the question “How well can you cope with your momentary stress-level” (slider 0-100) in daily life over four weeks. Multilevel models were conducted to test the effects of the coping strategies on situational coping. Additionally, gender differences were evaluated. RESULTS Positive Thinking (P=.03) and Active Stress Coping (P=.04) had significant positive impacts on situational coping in the total sample. For women, only Social Support had a significant positive effect on situational coping (P=.046). For men, only Active Stress Coping had a significant positive effect on situational coping (P=.001). Women had higher scores on the SCI scale Social Support than men (P=.007). CONCLUSIONS These results suggest that different coping strategies could be more effective in daily life for women than for men, which should be considered in the development of interventions aimed at reducing stress consequences through coping. Interventions taking gender into consideration might lead to better coping-outcomes than generalized interventions.

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