Mechanical Properties of Concrete with Recycled High-Density Polyethylene Macro Flat Fiber and Rice Hull Ash as Partial Replacement to Cement

This study determines the mechanical properties of concrete with the addition of recycled High-Density Polyethylene (HDPE) Macro Flat Fiber (MFF) and Rice Hull Ash (RHA) as partial replacement to cement. The objective of this study is to identify the optimum mix ratio for compressive and flexural strength of concrete. Various percentage of HDPE MFF (0.5%, 0.75%, and 1.0%) and 10% partial replacement of RHA to cement is incorporated in the mixture. The RHA is obtained through uncontrolled burning while HDPE MFF is collected through shredding and manual cutting. The results showed that the addition of HDPE MFF had a positive effect on the compressive and flexural strength of concrete. The optimum value is achieved on concrete with 0.5% HDPE MFF and no RHA, as it had showed an average of 31.87 MPa with a 18.04% increase in compressive strength, and an average of 4.532 MPa with a 17.78% increase for flexural strength. Moreover, the combination with RHA had not showed promising results. It had been concluded that the addition of recycled HDPE MFF with no RHA increases the compressive and flexural strength of concrete

Mechanical Properties of Concrete with Recycled High-Density Polyethylene Macro Flat Fiber and Rice Hull Ash as Partial Replacement to Cement

This study determines the mechanical properties of concrete with the addition of recycled High-Density Polyethylene (HDPE) Macro Flat Fiber (MFF) and Rice Hull Ash (RHA) as partial replacement to cement. The objective of this study is to identify the optimum mix ratio for compressive and flexural strength of concrete. Various percentage of HDPE MFF (0.5%, 0.75%, and 1.0%) and 10% partial replacement of RHA to cement is incorporated in the mixture. The RHA is obtained through uncontrolled burning while HDPE MFF is collected through shredding and manual cutting. The results showed that the addition of HDPE MFF had a positive effect on the compressive and flexural strength of concrete. The optimum value is achieved on concrete with 0.5% HDPE MFF and no RHA, as it had showed an average of 31.87 MPa with a 18.04% increase in compressive strength, and an average of 4.532 MPa with a 17.78% increase for flexural strength. Moreover, the combination with RHA had not showed promising results. It had been concluded that the addition of recycled HDPE MFF with no RHA increases the compressive and flexural strength of concrete

Multitraits evaluation of a Solanum pennellii introgression tomato line challenged by combined abiotic stress

Rising daily temperatures and water shortage are two of the major concerns in agriculture. In this work, we analysed the tolerance traits in a tomato line carrying a small region of the Solanum pennellii wild genome (IL12-4-SL) when grown under prolonged conditions of single and combined high temperature and water stress. When exposed to stress, IL12-4-SL showed higher heat tolerance than the cultivated line M82 at morphological, physiological, and biochemical levels. Moreover, under stress IL12-4-SL produced more flowers than M82, also characterized by higher pollen viability. In both lines, water stress negatively affected photosynthesis more than heat alone, whereas the combined stress did not further exacerbate the negative impacts of drought on this trait. Despite an observed decrease in carbon fixation, the quantum yield of PSII linear electron transport in IL12-4-SL was not affected by stress, thereby indicating that photochemical processes other than CO2 fixation acted to maintain the electron chain in oxidized state and prevent photodamage. The ability of IL12-4-SL to tolerate abiotic stress was also related to the intrinsic ability of this line to accumulate ascorbic acid. The data collected in this study clearly indicate improved tolerance to single and combined abiotic stress for IL12-4-SL, making this line a promising one for cultivation in a climate scenario characterized by frequent and long-lasting heatwaves and low rainfall

Braess' paradox: Some new insights

This paper examines some properties of the well-known Braess' paradox of traffic flow, in the context of the classical network configuration used by Braess. The paper shows that whether Braess' paradox does or does not occur depends on the conditions of the problem; namely, the link congestion function parameters and the demand for travel. In particular, this paper shows that for a given network with a given set of link congestion functions, Braess' paradox occurs only if the total demand for travel falls within a certain intermediate range of values (the bounds of which are dependent on the link congestion function parameters). The paper also shows that, depending on the problem parameters, adding a new link might not lead to a reduction in total system travel time, even if users are charged the marginal cost of traveling. On the other hand, there are ranges of values for the problem parameters for which the new link reduces total system travel time, as long as marginal cost pricing is implemented.

Can agronomic practices and cold-pressing extraction parameters affect phenols and polyphenols content in hempseed oils?

Hemp seed oil is an extraordinary dietary source of polyunsaturated fatty acids (PUFAs), to huge health benefits are related. PUFAs abundance could indeed contribute the oil turning rancid and deteriorating through oxidation. Thus, antioxidant compounds, characteristic of hemp seed matrix, should be more favorably extract to hopefully safeguard the oil stability. Moreover, antioxidants ability to counteract the onset of oxidative stress-related diseases could be employed to further enhance hemp seed oil functional value. In this context, phenols and polyphenols, which are poorly explored in hempseed oil so far, are thoroughly investigated by untargeted UHPLC-HRMS and MS/MS techniques in seed oils from Cannabis saliva L. cv USO31. Data recorded highlighted that hemp seed oil could contain, as minor constituents, saccharides, phenol compounds (some of them never described before - e.g. tyrosol hexoside, caffeoyl tartaric acid isomers), as well as flavonoids, of which glycosides of flavonols quercetin, kaempferol and isorhamnetin were the most representative. Glucuronide derivatives were also present. Multivariate principal-component analysis (PCA) highlighted that agronomic practices (e.g. plant density/m(2), use of fertilizers) and cold-pressing extraction parameters (e.g. temperature, nozzle size) massively affected the relative content of each compounds' class. Hemp seeds from soils, which did not undergo pre-seeding fertilization, and with 60 plant/m(2)crop density, ensured the highest production of phenols and polyphenols, whereas their abundance could be compromised when the plant density was halved

Multitraits evaluation of a Solanum pennellii introgression tomato line challenged by combined abiotic stress

Rising daily temperatures and water shortage are two of the major concerns in agriculture.In this work, we analysed the tolerance traits in a tomato line carrying a small region of the Solanum pennellii wild genome (IL12-4-SL) when grown under prolonged conditions of single and combined high temperature and water stress.When exposed to stress, IL12-4-SL showed higher heat tolerance than the cultivated line M82 at morphological, physiological, and biochemical levels. Moreover, under stress IL12-4-SL produced more flowers than M82, also characterized by higher pollen viability. In both lines, water stress negatively affected photosynthesis more than heat alone, whereas the combined stress did not further exacerbate the negative impacts of drought on this trait. Despite an observed decrease in carbon fixation, the quantum yield of PSII linear electron transport in IL12-4-SL was not affected by stress, thereby indicating that photochemical processes other than CO2 fixation acted to maintain the electron chain in oxidized state and prevent photodamage. The ability of IL12-4-SL to tolerate abiotic stress was also related to the intrinsic ability of this line to accumulate ascorbic acid.The data collected in this study clearly indicate improved tolerance to single and combined abiotic stress for IL12-4-SL, making this line a promising one for cultivation in a climate scenario characterized by frequent and long-lasting heatwaves and low rainfall

Understanding Travel Time Expenditures Around the World: Exploring the Notion of a Travel Time Frontier

Travel behavior researchers have been intrigued by the amount of time that people allocate to travel in a day, i.e., the daily travel time expenditure, commonly referred to as a “travel time budget”. Explorations into the notion of a travel time budget have once again resurfaced in the context of activity-based and time use research in travel behavior modeling. This paper revisits the issue by developing the notion of a travel time frontier (TTF) that is distinct from the actual travel time expenditure or budget of an individual. The TTF is defined in this paper as an intrinsic maximum amount of time that people are willing to allocate for travel. It is treated as an unobserved frontier that influences the actual travel time expenditure measured in travel surveys. Using travel survey datasets from around the world (i.e., US, Switzerland and India), this paper sheds new light on daily travel time expenditures by modeling the unobserved TTF and comparing these frontiers across international contexts. The stochastic frontier modeling methodology is employed to model the unobserved TTF as a production frontier. Separate models are estimated for commuter and non-commuter samples to recognize the differing constraints between these market segments. Comparisons across the international contexts show considerable differences in average unobserved TTF values. Copyright Springer Science+Business Media B.V. 2007Travel time frontier, Travel time budget, Travel time expenditure, International comparison, Stochastic frontier model, Activity-travel behavior,