Exergetic modeling and experimental performance assessment of a novel desiccant cooling system

New approaches to space conditioning of buildings are required to resolve economic, environmental, and regulatory issues. One of the alternative systems that is brought to agenda is the desiccant cooling systems, which may provide important advantages in solving air conditioning problems. This study deals with the performance analysis and evaluation of a novel desiccant cooling system using exergy analysis method. The system was designed, constructed and tested in Cukurova University, Adana, Turkey and has been successfully operated since 2008. This system consists of a desiccant wheel, heat exchangers, fans, evaporative cooler, electric heater unit and refrigeration unit. The exergy transports between the components and the destructions in each of the components of the desiccant cooling system are determined for the average measured parameters obtained from the experimental results. Exergy efficiencies of the system components are determined in an attempt to assess their individual performances and the potential for improvements is also presented. The exergetic efficiency values for the whole system on the exergetic product/fuel basis are calculated to range from round 32% to 10% at the varying dead (reference) state temperatures of 0-30 °C.     

The influence of polyaniline (PANI) coating on corrosion behaviour of zinc–cobalt coated carbon steel electrode

Zinc–cobalt alloy plating (ZnCo) was successfully deposited on carbon steel (CS) applying current of 2 mA with galvanostatic technique. Polyaniline film (PANI) was synthesized with cyclic voltammetry technique from 0.20 M aniline containing 0.20 M sodium tartrate solution on zinc–cobalt plated carbon steel (CS/ZnCo) electrode. PANI film characterized by scanning electron microscopy (SEM), was covered with a dark green-brown homopolymer film of strongly adherent homogeneous characteristic while the other one was plated with a porous light ZnCo one. The corrosion behaviour of zinc–cobalt deposited carbon steel electrodes with and without polyaniline (PANI) film in 3.5% NaCl solution was investigated with AC impedance spectroscopy (EIS) technique and anodic polarization curves. The results showed that PANI coating led to decrease of the permeability of metallic plating. The PANI homopolymer film provided an effective barrier property on zinc–cobalt coating and a remarkable anodic protection to substrate for longer exposure time.     

The Effect of Olive Leaf Addition on Antioxidant Content and Antioxidant Activity of “Memecik” Olive Oils at Two Maturity Stages

In this study, the effects of leaf addition, maturity stage and storage on the antioxidant content and activity of olive oils (cv. Memecik) were investigated in the 2008/09 and 2009/10 crop seasons. Olive fruits were harvested at two different maturity stages (early and late), and the leaves of the same cultivar were added at different rates (0, 1, and 3 %) prior to oil extraction. After extraction, the oil samples were stored for 18 months and total chlorophyll, α-tocopherol, total phenolic content and the antioxidant activity [DPPH^· (2,2-diphenyl-1-picrylhydrazyl) and ABTS^·+ (2,2-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid) radical scavenging] were determined at 6 month-intervals. Olive leaf addition induced a significant increase in total chlorophyll, α-tocopherol, total phenolic content, and antioxidant activities in both years (P < 0.001). During the storage period antioxidant content and antioxidant activities in the oils significantly decreased in both years (P < 0.001). However, the oils to which leaf material was added had higher antioxidant contents and activities than those without leaf material addition at the end of the 18-month storage period. After storage, the antioxidant content and DPPH^· radical scavenging activity of control (0 %) samples were lower than those in the leaf added samples (3 %). The data obtained from this study suggested that the addition of olive leaf to oils allowed more functional olive oils with higher antioxidant contents.     

Experimental diagnostics of ball bearings using statistical and spectral methods

Vibration measurements and signal analysis is widely used for condition monitoring of ball bearings as their vibration signature reveals important information about the defect development within them. Time domain analysis of vibration signature such as peak-to-peak amplitude, root mean square, Crest factor and kurtosis indicates defects in ball bearings. However, these measures do not specify the position and/or nature of the defects. Each defect produces characteristic vibrations in ball bearings. Hence, examining the vibration spectrum may deliver information on the type of defects. In this paper a test rig is designed and a pair of brand new commercial ball bearings is installed. The bearings run throughout their lifespan under constant speed and loading conditions. Vibration signatures produced are recorded and statistical measures are calculated during the test. When anomalies are detected in the statistical measures, vibration spectra are obtained and examined to determine where the defect is on the running surfaces. At the end of the test, the ball bearings are disassembled in order to take microscopic photos of the defects.     

Landfill Settlement with Decomposition and Gas Generation

A one-dimensional multiphase numerical model is developed to simulate the vertical settlement involving liquid and gas flows in a deformable (settling) municipal solid waste (MSW) landfill. MSW is represented by a chemical composition, and a global stoichiometric reaction is used to estimate the maximum yield of gas generation. Following the general assumption accepted in the literature, the gas generated by waste decomposition is assumed to comprise of methane (CH4) and carbon dioxide (CO2). The gas generation rate follows an exponentially decaying function of time. The gas generation model developed based on a first-order kinetic single-bioreactor approach includes the governing equations of gas migration, liquid flow, and landfill deformation. The Galerkin finite element method is used to solve the resulting equations. The model developed can be used to estimate the transient and ultimate settlements due to waste decomposition and gas generation in MSW landfills. The proposed model can estimate the waste porosity, gas pressure, liquid pressure, gas saturation, liquid saturation, and stress distributions in settling landfills. The results obtained for a deformable landfill are compared with a landfill having a rigid solid skeleton. Due to settlement, the depth of waste is 27% smaller in deformable landfills than that of the rigid ones.     

Effects of Polymerization and Briquetting Parameters on the Tensile Strength of Briquettes formed from Coal Coke and Aniline-Formaldehyde Resin

In this work, the utilization of aniline (C₆H₇N) formaldehyde (HCHO) resins as a binding agent of coke briquetting was investigated. Aniline (AN) formaldehyde (F) resins are a family of thermoplastics synthesized by condensing AN and F in an acid solution exhibiting high dielectric strength. The tensile strength sharply increases as the ratio of F to AN from 0.5 to 1.6, and it reaches the highest values between 1.6 and 2.2 F/AN ratio; it then slightly decreases. The highest tensile strength of F-AN resin-coke briquette (23.66 MN/m²) was obtained from the run with 1.5 of F/AN ratio by using (NH₄)₂S₂O₈ catalyst at 310 K briquetting temperature. The tensile strength of F-AN resin-coke briquette slightly decreased with increasing the catalyst percent to 0.10%, and then it sharply decreased to zero with increasing the catalyst percent to 0.2%. In general, the tensile strength of F-AN resin-coke briquette increased as increased the briquetting temperature in these tests contras with NaOH catalytic runs. The effect of pH on the tensile strength is irregular. As the pH of the mixture increases from 9.0 to 9.2, the tensile strength shows a sharp increase, and the curve reaches a plateau value between pH 9.3 and 9.9; then the tensile strength shows a slight increase after pH = 9.9.     

Hemodialysis for an unusual occurrence of leptospirosis in a nonendemic region

Leptospirosis, an endemic zoonotic disease caused by Leptospira, is frequently seen in tropical regions and areas with low socioeconomic status. The disease can present a range of symptoms from mild to fatal, with potential involvement of multiple organs. This case report describes the treatment and clinical course of a 44-year-old male patient infected with Leptospira semeranga patoc 1 and presenting with jaundice and renal failure. The patient was residing in the Syrian Refugee Camp in the arid city of Sanliurfa. This case serves as an example of a nonendemic occurrence of leptospirosis, and a brief overview of relevant literature on the subject is also provided.     

Getting a Grip on the Undrugged: Targeting β-Catenin with Fragment-Based Methods

Aberrant WNT pathway activation, leading to nuclear accumulation of β-catenin, is a key oncogenic driver event. Mutations in the tumor suppressor gene APC lead to impaired proteasomal degradation of β-catenin and subsequent nuclear translocation. Restoring cellular degradation of β-catenin represents a potential therapeutic strategy. Here, we report the fragment-based discovery of a small molecule binder to β-catenin, including the structural elucidation of the binding mode by X-ray crystallography. The difficulty in drugging β-catenin was confirmed as the primary screening campaigns identified only few and very weak hits. Iterative virtual and NMR screening techniques were required to discover a compound with sufficient potency to be able to obtain an X-ray co-crystal structure. The binding site is located between armadillo repeats two and three, adjacent to the BCL9 and TCF4 binding sites. Genetic studies show that it is unlikely to be useful for the development of protein–protein interaction inhibitors but structural information and established assays provide a solid basis for a prospective optimization towards β-catenin proteolysis targeting chimeras (PROTACs) as alternative modality.     

Monocytes Expose Factor XIII-A and Stabilize Thrombi against Fibrinolytic Degradation

Factor XIII (FXIII) is a transglutaminase that promotes thrombus stability by cross-linking fibrin. The cellular form, a homodimer of the A subunits, denoted FXIII-A, lacks a classical signal peptide for its release; however, we have shown that it is exposed on activated platelets. Here we addressed whether monocytes expose intracellular FXIII-A in response to stimuli. Using flow cytometry, we demonstrate that FXIII-A antigen and activity are up-regulated on human monocytes in response to stimulation by IL-4 and IL-10. Higher basal levels of the FXIII-A antigen were noted on the membrane of the monocytic cell line THP-1, but activity was significantly enhanced following stimulation with IL-4 and IL-10. In contrast, treatment with lipopolysaccharide did not upregulate exposure of FXIII-A in THP-1 cells. Quantification of the FXIII-A activity revealed a significant increase in THP-1 cells in total cell lysates following stimulation with IL-4 and IL-10. Following fractionation, the largest pool of FXIII-A was membrane associated. Monocytes were actively incorporated into the fibrin mesh of model thrombi. We found that stimulation of monocytes and THP-1 cells with IL-4 and IL-10 stabilized FXIII-depleted thrombi against fibrinolytic degradation, via a transglutaminase-dependent mechanism. Our data suggest that monocyte-derived FXIII-A externalized in response to stimuli participates in thrombus stabilization.