EXISTENCE AND ULAM STABILITY OF SOLUTIONS FOR NONLINEAR CAPUTO-HADAMARD FRACTIONAL DIFFERENTIAL EQUATIONS INVOLVING TWO FRACTIONAL ORDERS

In this paper, we study existence, uniqueness and Ulam-Hyers stability of solutions for integro-differential equations involving two fractional orders. By using Banach's fixed point theorem, we obtain some sufficient conditions for the existence and uniqueness of solution for the mentioned problem. Furthermore, we derive the Ulam-Hyers stability and the generalized Ulam-Hyers stability of solution. At the end, an illustrative example is discussed

The γ-polymorph of AgZnPO4 with an ABW zeolite-type framework topology

The γ-polymorph of the title compound, silver zinc orthophos­phate, was synthesized under hydro­thermal conditions. The structure consists of ZnO4, PO4 and AgO4 units. The coord­ination spheres of ZnII and PV are tetra­hedral, whereas the AgI atom is considerably distorted from a tetra­hedral coordination. Each O atom is linked to each of the three cations. An elliptic eight-membered ring system is formed by corner-sharing of alternating PO4 and ZnO4 tetra­hedra, leading to a framework with an ABW-type zeolite structure. The framework encloses channels running parallel to [100] in which the Ag cations are located, with Ag⋯Ag contacts of 3.099 (3) Å. This short distance results from d 10⋯d 10 inter­actions, which play a substantial role in the crystal packing. The structure of γ-AgZnPO4 is distinct from the two other polymorphs α-AgZnPO4 and β-AgZnPO4, but is isotypic with NaZnPO4-ABW, NaCoPO4-ABW and NH4CoPO4-ABW

Poly[ethyl­enediammonium [tris­[μ3-hydrogenphosphato(2−)]dicadmium] monohydrate]

The title compound, {(C2H10N2)[Cd2(HPO4)3]·H2O}n, was synthesized under hydro­thermal conditions. The structure of this hybrid compound consists of CdO6, CdO5 and PO4 polyhedra arranged so as to build an anionic inorganic layer, namely [Cd2(HPO4)3]2−, parallel to the ab plane. The edge-sharing CdO6 octa­hedra form infinite chains running along the a axis and are linked by CdO5 and PO4 polyhedra. The ethyl­ene­diammonium cation and the water mol­ecule are located between two adjacent inorganic layers and ensure the cohesion of the structure via N—H⋯O and O—H⋯O hydrogen bonds

Crystal structure of (1S,2R,4R,9S,11S,-12R)-9α-hydroxy-4,8-dimethyl-12-[(thio-morpholin-4-yl)methyl]-3,14-dioxatri-cyclo[9.3.0.02,4]tetradec-7-en-13-one

The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements.Peer reviewedPublisher PD

Design and Analysis of a Passive Lighting Device for a Sustainable Office Environment in Hot-Arid Climate Conditions

Visual comfort in office spaces improves not only productivity and wellbeing but also satisfaction and energy efficiency of the buildings. The objective of this research is to study the effect of one of the transporting daylighting systems (Anidolic Integrated Ceiling ‘AIC’) on the enhancement of the luminous interior environment and energy saving in office building through objective and subjective evaluations. The quantitative study was performed by measurement of the illuminance values in the physical model (1:4) under local luminous climate in two scenarios (with and without ‘AIC’) and by numerical simulation to calculate the daylight autonomy. The qualitative evaluations were achieved by using a field survey composed of four questions related to pleasantness, level of light and artificial lighting needs. Experimental study shows that the AIC offers high levels of illumination in quantitative terms result in moderate values of Daylight Factor (2% - 4%). Simulation results showed that more than 88% of energy consumption for electrical lighting can be saved. Subjective evaluation results indicate that in the test model (with AIC), 67% of participants felt more pleasant with the luminous environment, 74.19% considered that the level of light is sufficient and only 08 of 31 subjects need to use artificial lighting

DIVERSITÉ FLORISTIQUE DU MASSIF DU NADOR EN ZONE STEPPIQUE (TIARET, ALGÉRIE)

This study is devoted to Nador massif located in the steppe environment of Tiaret region in the west of Algeria. This massif is characterized by a diversity of flora composed of 121 taxa belonging to 38 families and 98 genera. Biological spectrum indicates a predominance of therophytes (38%) and chamaephytes (19%), geophytes (14%). The most important families are Poaceae and Asteraceae. Mediterranean element is relatively dominant (55%) according to chorologic plane. Shannon-Weaver e diversity index is relatively high (4.55) indicating a richly diverse site. Disturbance index (63.6%) reflects highly significant degree of massif vegetation disturbance, which also reflects a more open environment. To better understand the structure of vegetation using the classification is imperativ

Seismic Fragility Curves for Performance of Semi-rigid Connections of Steel Frames

A steel frame with a semi-rigid connection is one of the most widely used structural systems in modern construction. These systems are cheap to make, require less time to construct and offer the highest quality and reliable construction quality without the need for highly skilled workers. However, these systems show greater natural periods compared to their perfectly rigid frame counterparts. This causes the building to attract low loads during earthquakes. In this research study, the seismic performance of steel frames with semi-rigid joints is evaluated. Three connections with capacities of 50, 70 and 100% of the beam’s plastic moment are studied and examined. The seismic performance of these frames is determined by a non-linear static pushover analysis and an incremental dynamic analysis leading finally to the fragility curves which are developed. The results show that a decrease in the connection capacity increases the probability of reaching or exceeding a particular damage limit state in the frames is found. Doi: 10.28991/cej-2021-03091714 Full Text: PD

Study of land use/cover change impacts on thermal microclimate using QGIS in urban agglomeration

Thermal comfort and air quality are major concerns for people living in urban areas. In the last decades, cities are growing quickly and the increased urbanization is leading to the expansion of cities, which changes the properties and composition of the landscape. However, the surface temperatures are increasing, globally, because of anthropogenic climate change. Land use and land cover change have been shown to have a significant effect on climate through various pathways that modulate land surface temperature and rainfall. The objective of this study is to understand how the land use and land cover change affects the thermal microclimate in the city of Biskra (Algeria) using QGIS for the period between 2010 and 2020. The analysis results reveal that the mean temperature of the city has increased by ~4 °C during the past decade with the most accelerated warming (~7 °C) occurring during the recent decade (2010 to 2020). Our study shows also that 32% to 56% of this observed overall warming is associated with land use/cover and the largest changes are related to changing vegetation cover as evidenced by changes to both land use and land covers classes and normalized difference vegetation index (NDVI)