Thermodynamic properties of an interacting hard-sphere Bose gas in a trap using the static fluctuation approximation

A hard-sphere (HS) Bose gas in a trap is investigated at finite temperatures in the weakly-interacting regime and its thermodynamic properties are evaluated using the static fluctuation approximation (SFA). The energies are calculated with a second-quantized many-body Hamiltonian and a harmonic oscillator wave function. The specific heat capacity, internal energy, pressure, entropy and the Bose-Einstein (BE) occupation number of the system are determined as functions of temperature and for various values of interaction strength and number of particles. It is found that the number of particles plays a more profound role in the determination of the thermodynamic properties of the system than the HS diameter characterizing the interaction, that the critical temperature drops with the increase of the repulsion between the bosons, and that the fluctuations in the energy are much smaller than the energy itself in the weakly-interacting regime.Comment: 34 pages, 24 Figures. To appear in the International Journal of Modern Physics

Résidus de pesticides organochlorés chez les bivalves et les poissons de la lagune de Moulay Bousselham (Maroc)

Oragnochlorine pesticide residues in bivalves and fishes fromthe Moulay Bousselham lagoon (Morocco) This work involves an assessment of the degree of contamination by Organochlorine pesticides (POC) of clams (Venerupis deccusatua), mussels (Mytilus edulis) and fish mullet (Mugil cephalus) from the Moulay Bousselham lagoon. 12 organochlorine pesticides are considered in this study: DDT and its metabolites (DDD, DDE), ƒÁHCH and ƒ¿HCH, aldrin, endrin, dieldrin, heptachlor, heptachlor epoxide, hexachlorobenzene (HCB) and ƒ¿ endosulfan. The study showed an important contamination by organochlorine pesticides, DDT and its metabolites present the high concentrations at all species, lindane and its isomers are also present but at low concentrations. At clams, concentrations of POC varied between 9.2 to 51.72 ng/g (dry weight) with a maximum detected in the station of oued Drader. Mussels were less contaminated that clams, concentrations varied between 4.53 to 16.81 ng/g. The contamination of mullet by POC is more marked with a concentrations varied between 12.52 ng/g recorded in November to 82.39 ng/g detected in May. The strong proportion of DDE in relation to DDT showed that the major ofcontamination is very old. The quantities of organochlorine pesticides revealed at clams, mussels and mulled of Moulay Bousselham lagoon don’t exceed the maximal limits in marines organisms. The consumption of these species don’t have actually any problem in public health

Pre-harvest foliar application of mineral nutrients to retard chlorophyll degradation and preserve bio-active compounds in broccoli

Foliar application of micronutrients has become a common farm management practice to increase the overall yield of various crops. However, the effects of foliar fertilization on shelf life and postharvest quality of the crops are rather under-researched. The aim of this field experiment was to evaluate the effect of foliar application of individual mineral nutrients (calcium (Ca), zinc (Zn), manganese (Mn), and iron (Fe) on pre and postharvest quality of broccoli. The broccoli plants were subjected to single foliar sprays of either Ca, Fe, Zn, or Mn, which was repeated four times during plant growth at a 1 g/kg concentration. Once harvested, the broccoli heads were refrigerated at 4 °C for 28 days. Our results indicated that foliar application of Ca, Zn, Mn, and Fe did not have a significant effect on plant growth parameters, apart from enhancing Soil Plant Analysis Development (SPAD) chlorophyll meter values. However, during postharvest, foliar application treatment showed a positive response on weight loss during storage and reduction in yellowing of the broccoli heads. Foliar treatments increased the concentration of Nitrogen (N), Phosphorus (P), Ca, Zn, Mn and Fe significantly in the broccoli head tissue. Total chlorophyll content, total phenolic compound, ascorbic acid, peroxidase activity, glucoraphanin and glucobrassicin and flavonoids were significantly increased by all foliar treatments. Crude protein content and sulforaphane were enhanced by Ca and Mn treatments. Overall, foliar application of the investigated mineral nutrients may prove beneficial in improving the shelf-life and nutrient content of broccoli during postharvest handling and storage

Flexural Behavior of Lightweight Composite Ferrocement Plates

In recent years, producing lightweight structures is considered as one of the most important application of concrete. It has extensive applications in the architect and insulation work. The main objective of this study is to investigate the behavior and the performance of lightweight ferrocement (LWF) composite plates with lightweight materials as filler materials in flexural. Fifteen lightweight ferrocement (LWF) composite plates were investigated by conducting flexural tests. The main variables are (the thickness of plates, the type of filler materials, the type and number of layers of meshes). The behavior of lightweight ferrocement (LWF) composite plates is investigated by conducting flexural tests on fifteen simply supported rectangular plates under three lines loadings. Fifteen plates represented in twelve lightweight ferrocement (LWF) plates and three conventional reinforced concrete (RC) plates. The ferrocement plates were divided into three groups according to the thickness of plates 6cm, 8cm and 10cm. The structural performances of the LWF and RC plates are investigated in terms of crack load, load-deflection curves, stiffness, energy absorption capacity, ductility index, ultimate flexural load-to-weight ratio, load-strain curves, crack patterns, and the failure modes. The test results revealed remarkable enhancement in the flexural behavior and potential application of lightweight ferrocement (LWF) composite plates to produce lightweight structural elements as compared to that of the reinforced concrete (RC) plates, which lead towards the industrialization of building system and meets with innovation and expansible application of concrete construction technology results in better efficiency of developing of lightweight composite ferrocement plates

Time-resolved photoelectron and photoion fragmentation spectroscopy study of 9-methyladenine and its hydrates: a contribution to the understanding of the ultrafast radiationless decay of excited DNA bases.

The excited state dynamics of the purine base 9-methyladenine (9Me-Ade) has been investigated by time- and energy-resolved photoelectron imaging spectroscopy and mass-selected ion spectroscopy, in both vacuum and water-cluster environments. The specific probe processes used, namely a careful monitoring of time-resolved photoelectron energy distributions and of photoion fragmentation, together with the excellent temporal resolution achieved, enable us to derive additional information on the nature of the excited states (pp*, np*, ps*, triplet) involved in the electronic relaxation of adenine. The two-step pathway we propose to account for the double exponential decay observed agrees well with recent theoretical calculations. The near-UV photophysics of 9Me-Ade is dominated by the direct excitation of the pp* (1Lb) state (lifetime of 100 fs), followed by internal conversion to the np* state (lifetime in the ps range) via conical intersection. No evidence for the involvement of a ps* or a triplet state was found. 9Me- Ade–(H2O)n clusters have been studied, focusing on the fragmentation of these species after the probe process. A careful analysis of the fragments allowed us to provide evidence for a double exponential decay profile for the hydrates. The very weak second component observed, however, led us to conclude that the photophysics were very different compared with the isolated base, assigned to a competition between (i) a direct one-step decay of the initially excited state (pp* La and/or Lb, stabilised by hydration) to the ground state and (ii) a modified two-step decay scheme, qualitatively comparable to that occurring in the isolated molecule