Effect of thermal insulation using leather and carpentry wastes on thermal comfort and energy consumption in a residential building

In this work, we investigate the effect of the thermal insulation by leather wastes (wet-blue chrome shavings and buffing dust) and carpentry wastes (wood shavings and sawdust) on the energy consumption of a model building using the average climatic data of the city of Casablanca (Morocco). For this study, we used the dynamic thermal simulation tool “TRNSYS 16” which predicts the thermal behavior of building and systems associated with it. Using this software, we evaluated the effect of the above material wastes on thermal comfort and building energy consumption. The type and the thickness of the materials were considered as variants to choose the better solution. The average temperatures of building supposed thermally insulated compared to those obtained without insulation clearly show the thermal insulation ability of tested materials during the cold and warm periods of the year. Increasing the thickness of the insulator makes locals increasingly comfortable. Because of their performance, leather and carpentry wastes can compete with conventional insulating materials such as polystyrene and cork.     

Drug delivery from nonpeptidic α-amino acid containing polyamides

New nonpeptidic α-amino acid-based polyamides were used for drug delivery. Benzocaine was covalently linked via a spacer to N-protected poly(l-cystyl-l-cystine) and to poly(adipoyl-l-lysine). Its release by α-chymotrypsin attack was followed by UV. It was nearly quantitative within two days with l-cystine-based polyamide. Protected forms of these polyamides were used as matrices. Release of benzocaine entrapped in polyamide from (l-cystine) was controlled by diffusion. When entrapped in polyamide from (l-lysine) it was controlled by diffusion and swelling. Received: 10 January 1997/Accepted: 23 January 1997     

Risk factors for severe injury in cyclists involved in traffic crashes in Victoria,Australia

This study examines the impact of cyclist, road and crash characteristics on the injury severity of cyclists involved in traffic crashes reported to the police in Victoria, Australia between 2004 and 2008. Logistic regression analysis was carried out to identify predictors of severe injury (serious injury and fatality) in cyclist crashes reported to the police. There were 6432 cyclist crashes reported to the police in Victoria between 2004 and 2008 with 2181 (33.9%) resulting in severe injury of the cyclist involved. The multivariate analysis found that factors that increase the risk of severe injury in cyclists involved in traffic crashes were age (50 years and older), not wearing a helmet, riding in the dark on unlit roads, riding on roads zoned 70 km/h or above, on curved sections of the road, in rural locations and being involved in head-on collisions as well as off path crashes, which include losing control of vehicle, and on path crashes which include striking the door of a parked vehicle. While this study did not test effectiveness of preventative measures, policy makers should consider implementation of programs that address these risk factors including helmet programs and environmental modifications such as speed reduction on roads that are frequented by cyclists.     

LMV651提高系统设计的质量与效率

以便携式电子产品为例,系统设计工程师要面对成本压力,因为产品价格必须尽量降低,才可凭借价格优势,抢占更大的市场。放大器是这类便携式系统的重要组成部分,因为这类器件可以执行信号放大、滤波、转换及其他功能。     

Magnesium vacancies and hydrogen doping in MgH2 for improving gravimetric capacity and desorption temperature

Performing an ab initio analysis, we inspect the effect of magnesium vacancies and hydrogen doping on the magnesium hydride (MgH₂). The Korringa – Kohn – Rostoker method integrated with the coherent potential approximation is used to perform our calculations. In particular, we find that the gravimetric capacity of MgH₂ increases from 7.658 to 9.816 wt% when the concentrations of magnesium vacancies and hydrogen dopant atoms increase from 0 to 10%. Concretely, the results reveal that the magnesium vacancies and the hydrogen doping have a beneficial effect on the hydrogen storage properties of the hydride by decreasing its desorption temperature and stability. This decrease can be explained on the one hand by the diminution of the number of Mg atoms that establish strong bonds with H atoms, and on the other hand by using the density of states, which indicates that when the concentrations increase, the Mg and H states shift to the conduction band. We also obtain that the value of the desorption temperature can be controlled by varying the concentrations of magnesium vacancies and hydrogen dopant atoms from 4.2 to 5.8% in order to reach the optimum range 289–393 K for the practical use of fuel cell vehicles.     

Modeling heat transfer and air circulation by convection in bottom-heated agricultural greenhouses

In agricultural greenhouses, effective heating systems are essential for maintaining proper temperature control and air circulation during the winter. This study delves into the analysis of heat exchange through natural convection within heated greenhouses, with a particular emphasis on the impact of bottom heating. Two distinct types: mono-chapel and bi-chapel, each featuring triangular or spherical roofs are examined. To capture the variable roof shapes, we employ a change-of-variable method, and the numerical solutions are obtained using the finite volume method. The results show that heat transfer is enhanced by increasing the Rayleigh number. This improvement differs according to the shape of the roof. Heat transfer decreases by about 5% for the spherical mono-chapel case compared to the triangular case for Ra = 10³. For Ra = 10⁵, the monospherical case favors heat transfer, with an increase of 0.35% compared to the triangular case. In the case of bi-chapel roof, heat transfer is greater with a triangular roof for Ra = 10³, showing an increase of 6.4% compared to the spherical case. This study not only sheds light on the fundamental aspects of heat transfer in greenhouses but also provides valuable insights for optimizing greenhouse design based on specific roof configurations and heating conditions.     

Surface modification of p-Si by a polyethylenimine coating: influence of the surface pre-treatment. Application to a potentiometric transducer as pH sensor

p-Si electrodes coated with linear polyethylenimine (L-PEI) allow the fabrication of a pH sensitive film for potentiometric transducers. The coating is realized in one step through the anodic oxidation of pure ethylenediamine (EDA) charged with 0.1 M LiCF₃SO₃ (Lithium Triflate). Such an electrochemical procedure leads to the thickness control of the coating. The best silicon surface pre-treatment before any coating is obtained with potassium dichromate in sulfuric acid, which leads to OH-terminated p-Si. This pre-treatment allows a uniform thin coating. In this work, the thickness is 2.6 nm. The pH response is high and close to 50 mV per pH unit.     

Stable routing protocol based on fuzzy logic system in vehicular ad hoc networks

Vehicular ad‐hoc networks have several roles in alert messages dissemination between vehicles in danger, the most important role is to provide helpful information for drivers (eg, road traffic state). But, some performance improvements are frequently needed in terms of routing. Hence, several clustering approaches have been proposed to optimize the network services. These approaches are based on increasing data delivery, reducing data congestion, and dividing the traffic into clusters. However, a stable clustering algorithm is always required in order to ensure the data dissemination in a dense, mobile, or a large‐scale environment. Therefore, in this paper, we have proposed a stable routing protocol based on the fuzzy logic system, which can deliver alert messages with minimum delay and improve the stability of clusters structure by generating only a small number of clusters in the network. In this work, the fuzzy logic system has been used to create the clusters and select a cluster head for each cluster. We have used the network simulator (NS2) to generate the results. As a result, we could reduce the cluster head changes and increase the cluster member lifetime compared with recent approaches.     

New Scattering Matrix Model for Modeling Ferrite Media Using the TLM Method

This paper aims to extend the transmission line matrix method with a hybrid symmetrical condensed node (HSCN) to model ferrite media in the time domain. To take into account the anisotropy and dispersive properties of ferrite media, equivalent current sources are incorporated into supplementary stubs of the original HSCN. The scattering matrix of the proposed HSCN is provided, and the validity of this approach is demonstrated for both transversely and longitudinally magnetized ferrites. Agreement is achieved between the results of this approach and those of the theoretical and the finite‐difference time‐domain method.