Kinetics and thermodynamics of sucrose crystallization from pure solution at different initial supersaturations

Growth rates of sucrose crystallization from pure solutions of initial relative supersaturation levels between 0.094 and 0.181 were studied in agitated crystallizer at 313.13 K. Birth and spread model was applicable for the obtained growth rate data in this range of supersaturation and used to estimate the principal growth parameters. The estimated interfacial free energy varied inversely with supersaturation from 0.00842 to 0.00461 J/m2, respectively. The obtained kinetic coefficient changed with the initial supersaturation from 9.45 × 10− 5 to 2.79 × 10− 7 m/s. The corresponding radius of the 2D (two dimensional) critical nucleus varied from 7.47 × 10− 9to 1.46 × 10− 9 m. Predominance of surface integration or volume diffusion mechanism during the growth process was assessed using the calculated activation free energies of the 2D nucleation process. An acceptable confirmation of the calculated radius of the critical 2D nucleus was found using atomic force microscopy (AFM) technique. The calculated interfacial free energy between the saturated sucrose solution and the crystal surface was found to be 0.02325 J/m2.The funding from Syrian Ministry of Higher Education and FEUP (Portugal) is highly appreciated

The battle over Syria's reconstruction

Reconstruction is becoming the new battleground in the Syrian conflict—its continuation by other means. It is instrumentalized by the regime as a way to reconsolidate its control over the country and by rival regional and international powers to shape the internal balance of power and establish spheres of influence in the country. The paper examines the Asad regime’s practices, including co-optation of militia leaders via reconstruction concessions and use of reconstruction to clear strategic areas of opposition-dominated urban settlements. The paper then surveys how the geopolitical struggle in Syria has produced an asymmetry as regards reconstruction: those powers that lost the geo-political contest on the ground seek to use geo-economic superiority to reverse the geo-political outcome. Then the impact of proxy wars and spheres of influence in the country on the security context for reconstruction is examined. Finally, the reconstruction initiatives of the various external parties are assessed, including Russia, Iran and Turkey as well as the spoiler role by which the US seeks to obstruct reconstruction that would spell victory in Syria for its Russian and Iranian rivals.PostprintPeer reviewe

Glomerulocystic kidney disease

Glomerulocystic disease is a rare renal cystic disease with a long descriptive history. Findings from recent studies have significantly advanced the pathophysiological understanding of the disease processes leading to this peculiar phenotype. Many genetic syndromes associated with glomerulocystic disease have had their respective proteins localized to primary cilia or centrosomes. Transcriptional control of renal developmental pathways is dysregulated in obstructive diseases that also lead to glomerulocystic disease, emphasizing the importance of transcriptional choreography between renal development and renal cystic disease

Comparative analysis of residential building envelopes newly implementing the building insulation code in Damascus

The selection of envelope construction technique has the highest impact on sustaining indoor thermal comfort while reducing energy consumed for heating and cooling. Numerous insulation codes are implemented worldwide to improve building envelope modification. Each country has set envelope transmittances criteria, materials, techniques and simulation tools differently based on its climate zones and construction sector adaptability. The housing sector in Syria is the focus of energy conservation being responsible of half of the energy consumption in the country. Syrian post-conflict residential buildings are challenged by the new implementation of Building Insulation Code. This code has opted for a “fabric first” dwellings design approach with mandatory U-value standards. Hence, like many energy-related regulations in Syria it has been dropped because the construction sector has not been able to cope with them, forced by speculators to keep costs low. Another reason is that building thermal performance modeling has not been used to comply with the new insulation code in Syria. The research aims to examine the potential relevance of the Insulation Code in informing post-war social housing envelope structures in Damascus. It evaluates compliant building envelope structures compared to conventional building in terms of transmittance properties, simulated thermal loads (IESVE) and cost–energy trade-off. The research findings reveal an improvement in U-values of 78.5%, 31.5%, 92.7% and 90.2% achieved in compliant cases 1, 3, 4 and 5, respectively, compared to conventional case-2. The simulation demonstrated best improvement in total heating loads up to 85% achieved in case-4. Hence, the improved U-value lead to improvement in winter heating loads but overheating in summertime. The simulation was found useful but not enough to optimize envelope performance through interdisciplinary decision that contributes positively to Syrian post-war circumstances. The cost analysis found an increase in wall initial construction costs, amounting to 36.4%, 27.3%, 54.6% and 45.5% in cases 1, 3, 4 and 5 with long payback periods. These findings spark a new agenda for Insulation Code improvement. The proposed simplified criteria offer practitioners more understanding to customize their own list of envelope structure parameters based on the climatic zone resulting in a shift in envelope selection from input to a more output oriented

Multiple-criteria optimization of residential buildings envelope toward nZEBs: simplified approach for Damascus post-war

Syria faces significant challenges in optimizing residential building energy consumption to subsequently reduce CO2 emissions due to its conventional construction methods and systems, exacerbated by the recent conflict. Post-war re-construction provides new opportunities for improvement in building standards through the 2009 BIC insulation code towards nearly Zero Energy Buildings (nZEBs). However, the decline in economy growth poses significant challenges. In this study, we formulate a simplified building envelope selection approach using multi-criterion optimization methodology based on simulated thermal loads using IESVE and cost-energy trade-off. IESVE was used to evaluate the thermal performances of five cases representing 5 different building envelope structures on existing buildings in Damascus, Syria. Four out of the five cases were BIC compliant, and their thermal performances and cost energy trade-offs were evaluated against that of a conventional building representing the construction-as-usual case. Payback on the investment in insulation improvement of the envelope structures were also calculated. The results overall shows that the envelope structures incorporating insulation layer reduced annual heating, cooling, and combined energy loads of those buildings. Comparatively, these improvements were slightly better under winter conditions than in summer. Based on payback period analysis, none of the improvements provided acceptable economical payback within five years, as energy consumption tariffs were extremely low and insulation material costs were extremely high. A Multi-Criteria Decision Making (MCDM) framework was developed and applied to the cases investigated. Based on the limitations of the BIC, no optimal solution was obtained. However, the framework provides a good basis for stakeholders to make sound decisions in transitioning buildings especially under post war context towards nZEBs

Capillary bundle model for the computation of the apparent permeability from pore size distributions

International audienc