Experimental and Modeling Study of Gas Adsorption in Metal-Organic Framework Coated on 3D Printed Plastics

Indiana University-Purdue University Indianapolis (IUPUI)Metal-organic frameworks (MOFs) are a class of compounds consisting of metal ions or clusters coordinated to organic ligands in porous structure forms. MOFs have been proposed in use for gas adsorption, purification, and separation applications. This work combines MOFs with 3D printing technologies, in which 3D printed plastics serve as a mechanical structural support for MOFs powder, in order to realize a component design for gas adsorption. The objective of the thesis is to understand the gas adsorption behavior of MIL-101 (Cr) MOF coated on 3D printed PETG, a glycol modified version of polyethylene terephthalate, through a combined experimental and modeling study. The specific goals are: (1) synthesis of MIL-101 (Cr) MOFs; (2) nitrogen gas adsorption measurements and microstructure and phase characterization of the MOFs; (3) design and 3D printing of porous PETG substrate structures; (4) deposition of MOFs coating on the PETG substrates; and (5) Monte Carlo (MC) modeling of sorption isotherms of nitrogen and carbon dioxide in the MOFs. The results show that pure MIL-101 (Cr) MOFs were successfully synthesized, as confirmed by the scanning electron microscopy (SEM) images and X-ray diffraction (XRD), which are consistent with literature data. The Brunauer-Emmett-Teller (BET) surface area measurement shows that the MOFs samples have a high cover- age of nitrogen. The specific surface area of a typical MIL-101 (Cr) MOFs sample is 2716.83 m2/g. MIL-101 (Cr) also shows good uptake at low pressures in experimental tests for nitrogen adsorption. For the PETG substrate, disk-shape plastic samples with a controlled pore morphology were designed and fabricated using the fused deposition modeling (FDM) process. MOFs were coated on the PETG substrates using a layer-by-layer (LbL) assembly approach, up to 30 layers. The MOFs coating layer thicknesses increase with the number of deposition layers. The computational model illustrates that the MOFs show increased outputs in adsorption of nitrogen as pressure increases, similar to the trend observed in the adsorption experiment. The model also shows promising results for carbon dioxide uptake at low pressures, and hence the developed MOFs based components would serve as a viable candidate in gas adsorption applications

Stab wounds in Bulawayo, Zimbabwe: a four year audit

A CAJM journal article.Outside South Africa the problem of stab wounds has not received much attention in the African medical literature. This problem has not been studied before in Zimbabwe. From a review of the literature, supported by the material in this paper, it is clear, that most stab wounds affect the chest and abdomen. Clinicians should therefore be aware of the various management options of such injuries. This study was carried out to determine the pattern of stab wounds in our practice and to analyze the results of our management of patients with such injuries. The relevant literature is reviewed and suggestions are made to bring our management of stab wounds in line with current management trends

Theoretical exploration of construction site management practices

The construction industry is vital to the existence of other industrial sector and provides the environment under which other sectors operate. It is the largest industry and contributes about 10% of the gross national product (GNP) in industrial-ized countries. It also plays a major role in development and reaching the goals of society. The current study aims to establish the factors required in the manage-ment of good site management on construction sites in Swaziland. The study is conducted with reference to existing theoretical literature, published and un-published research. The study is mainly a literature review/survey on site man-agement practices on construction sites. Findings emanating from the study reveal that realistic studies have identified a number of problems on site management practices such as management and administration problems, technical problems and communication problems. It also indicates that site management involves a mixture of activities which turn basic sources to a finished product. The study presents a strong background on site management practices on construction sites in the Swaziland construction industry

Impact of phosphamidon and its metabolites on histopathology of the liver, gill and intestine of Labeo rohita

Impact of phosphamidon, an organophosphorus pesticide and its metabolites viz. dimethyl phosphoric acid and 2-chloro 2-diethyl carbamoylmethyl vinyl acid on histopathology of a common teleost, Labeo rohita was studied by exposing the fish to sub-lethal concentrations which were taken as 1/3rd of LC50 and were equal to 0.0123 ppm for phosphamidon, 0.0160 ppm for dimethyl phosphoric acid and 0.0167 ppm for 2-chloro 2-diethyl carbamoylmethyl vinyl acid respectively. The results revealed that hepatocytes in the liver were markedly swollen and exhibited hydropic degeneration. Fusion of primary lamellae and moderate congestion of blood vessels were evident in the gill. Intestine showed degeneration of mucosa and cellular infiltration in sub-mucosa. LC50 values and histopathological photomicrographs suggest that phosphamidon is more toxic as compared to dimethyl phosphoric and 2-chloro 2-diethyl carbamoylmethyl vinyl acid