Hydrogen and carbon nanostructure formation from methane cracking over iron and zeolite based catalysts

The production of hydrogen by the catalytic cracking of methane was investigated. An extensive study was undertaken on two categories of materials, namely iron-containing wastes and prepared catalysts, which include palladium-based catalysts, nickel-based catalysts and a copper-based catalyst. Three types of iron-containing waste materials were examined as pre-catalysts. The iron waste samples comprised a biogenic sample from a local Landfill site; waste residue sample from an old local nail works site and Red Mud. The resulting waste iron catalysts are environmentally benign and may be “thrown away” following use. The biogenic sample presented an unusual tubular morphology resulting from its biogenesis. All these materials possessed significant peak activity for hydrogen production at 800 °C. Significant carbon deposition occurred on these samples. Calcination of biogenic and waste residue samples at 900 °C enhanced performance. Carbon was deposited in the form of carbon filaments on the waste residue sample. The addition of Pd promoted the biogenic sample’s activity but poisoned the waste residue sample. Cracking of methane over palladium-containing zeolite catalysts has also been studied. Pd/H-ZSM-5 exhibited the highest peak hydrogen formation rate at 750 °C and the highest amount of carbon was produced at 900 °C. The addition of Ni, Co, Cu and Fe dopants did not improve performance. The effect of support type (H-ZSM-5, -Al2O3 and SiO2) on the Pd catalyst performance was also investigated, with -Al2O3 producing the best activity. All post-reaction Pd catalysts showed the formation of carbon filaments. On comparing the catalytic activity of Pd/H-ZSM-5, Ni/H-ZSM-5 and Cu/H-ZSM-5, it was found that Pd/H-ZSM-5 catalyst possessed the highest activity, while Ni/H-ZSM-5 and Cu/H-ZSM-5 catalysts showed lower activity and similarity to each other in behaviour. Carbon filaments were formed over Pd/H-ZSM-5 and Cu/H-ZSM-5 but did not form over Ni/H-ZSM-5. It was observed that the carbon filaments only grow at higher Ni-loading on the zeolite. The catalytic activities of Ni on different supports were evaluated and SiO2 was found to be the most effective support

Endocannabinoid and lipid metabolism genes network analysis in adipose and liver tissue of dairy cows during the transition period

During the transition period dairy cows are exposed to enormous metabolic changes. These changes could affect the overall health and production. Two experiments were conducted on transition cows to evaluate the 1) effects of body condition score (BCS) on the endocannabinoid system and lipid metabolism gene expression in adipose tissue; and 2) effects of rumen-protected methionine on the endocannabinoid system in liver tissue. In the first study, cows were retrospectively classified according to their BCS at -3 wk from parturition into two groups: HiBCS (BCS ≥ 3.75) or LoBCS (BCS ≤ 3.25 ). Adipose tissue at -10, 7, and 20 d around parturition was used to examine mRNA expression via qPCR of endocannabinoid receptors (CNR1, CNR2), enzymes that synthesize endocannabinoid (NAPEPLD), enzymes that degrade endocannabinoids (FAAH, NAAA, MGLL), and the hormone precursor proopiomelanocortin (POMC). We also examined mRNA expression via qPCR of genes associated with lipolysis (LIPE, ABDH5, ATGL), fatty acid oxidation (CPT1A, CPT2, ACADVL, ACOX1), oxidative stress (SOD1, SOD2), and genes that are involved in inflammation (TLR9, TLR4, NFE2L2). Expression of CNR2 and NAPEPLD was greater at 7 d in LoBCS due to lower expression at the same time in HiBCS. The expression of FAAH was upregulated at d 7 and 20 in LoBCS than HiBCS cows. Expression of MGLL was overall greater across time in LoBCS than HiBCS, LoBCS had a tendency for greater overall expression of POMC across time. Regarding the genes associated with lipolysis, LoBCS compared with HiBCS cows had overall greater expression of ABDH5, LIPE and ATGL, indicating a greater state of basal lipolysis over time. Among genes related with fatty acid oxidation the expression of CPT1A and ACADVL was greater in HiBCS than LoBCS due to greater expression at -10 and 7 d. For the mitochondrial enzyme SOD2, important for clearing reactive-oxygen species that cause cellular stress and inflammation, we observed an interaction of BCS × day due to higher expression at d 7 in LoBCS than HiBCS. There was an overall BCS effect on the expression of SOD1 due to greater expression in LoBCS compared with HiBCS. In the second experiment, cows were fed experimental diets consisting of a basal control diet (CON) or rumen-protected methionine-supplemented (MET) during the transition period (-21 through 30 days in milk). The liver was biopsied at -10, 7, 20 and 30 days relative to parturition. Gene expression was determined through qPCR for endocannabinoid receptors (CNR1, CNR2), enzymes that synthesize endocannabinoid (NAPEPLD), enzymes that degrade endocannabinoid (FAAH, NAAA, MGLL), and the hormone precursor proopiomelanocortin (POMC). A significant interaction of treatment × day was observed for the endocannabinoid receptor CNR2 associated with lower expression in MET compared with control cows on d -10. There was an overall greater expression of FAAH, MGLL, NAAA and the EC-synthesizing enzyme NAPEPLD in MET compared with control cows. Cows supplemented with MET had greater in vitro blood neutrophil phagocytosis, neutrophil oxidative burst and monocyte oxidative burst. Results from experiment 1 indicate that expression of the endocannabinoid system and lipid metabolism genes in adipose tissue may be associated with BCS. A potential linkage between those pathways and risk of disorders postpartum remains to be determined. Results from experiment 2 suggest that the alterations in the hepatic EC signaling network in response to MET might be involved in the positive effect on performance and liver function

An overview of cloud services adoption challenges in higher education institutions

Information Technology (IT) plays an important role in enabling education services be delivered to users. Most education online services in universities have been run on the cloud to provide services to support students, lecturers, researchers and administration staff. These are enabled with the emergence of cloud computing in the world of IT. Cloud computing offers on demand Internet-based computing services. This paper presents an overview of cloud computing adoption in higher education, mainly tertiary institutions and universities. The focus of the paper is the challenges of cloud computing in higher education. It introduces the background to cloud computing and reviews research on adoption challenges in higher education institutions. These challenges are important as they provide an overview of the adoption of cloud in higher education. The authors proposed an integrated reference model based on the challenges in the literature integrated with TAM model to investigate the factors influence the users’ attitudes and behaviors toward using cloud education services in universities ICT provision

Security risk factors that influence cloud computing adoption in Saudi Arabia government agencies

Cloud computing technologies play a substantial role in public organizations and private sector companies since it reduces the cost of using information technology services and allows users to access the service anytime and everywhere, whilst only paying for what they use. In developing countries, such as Saudi Arabia, the cloud computing is still not widely adopted, compared to countries in the west. In order to promote the adoption of cloud computing, it is important to recognize that an important and specific issue related to cloud computing is the potential and perceived security risks posed by implementing such technology. Therefore, the aim of this research is to investigate the security risk factors that influence organization to adopt cloud computing in a Saudi Arabia context. This research proposed a framework for the successful adoption of cloud computing, focused on risks when implementing security in the cloud system

Determination of the yield loci of four sheet materials (AA6111-T4, AC600, DX54D+Z, and H220BD+Z) by using uniaxial tensile and hydraulic bulge tests)

In sheet metal forming simulation, a flow curve and a yield criterion are vital requirements for obtaining reliable numerical results. It is more appropriate to determine a flow curve by using biaxial stress condition tests, such as the hydraulic bulge test, than a uniaxial test because hardening proceeds higher strains before necking occurs. In a uniaxial test, higher strains are extrapolated, which might lead to incorrect results. The bulge test, coupled with the digital image correlation (DIC) system, is used to obtain stress–strain data. In the absence of the DIC system, analytical methods are used to estimate hardening. Typically, such models incorporate a correction factor to achieve correlation to experimental data. An example is the Chakrabarty and Alexander method, which uses a correction factor based on the n value. Here, the Chakrabarty and Alexander approach was modified using a correction factor based on normal anisotropy. When compared with DIC data, the modified model was found to be able to better predict the hardening curves for the materials examined in this study. Because a biaxial flow curve is required to compute the biaxial yield stress, which is an essential input to advanced yield functions, the effects of the various approaches used to determine the biaxial stress–strain data on the shape of the BBC2005 yield loci were also investigated. The proposed method can accurately predict the magnitude of the biaxial yield stress, when compared with DIC data, for all materials investigated in this study

A green approach for the removal of Sr(II) from aqueous media: kinetics, isotherms and thermodynamic studies

Adsorption efficiency of native, NaOH-treated and immobilized peanut husk and sugarcane bagasse for Sr(II) removal was studied in batch mode. In view of promising adsorption efficiency of peanut husk versus sugarcane bagasse, the biosorption behaviour of the Sr(II) ions onto peanut husk (native and modified) was studied as a function of pH, biosorbent dose, contact time, initial metal ion concentration and temperature for the maximum removal of Sr(II) ions. Linear and non-linear pseudo-first and second-order kinetic models were applied and value of R2 and six non-linear regression error functions, namely hybrid fractional error function (HYBRID), Marquardt's percent standard deviation (MPSD), average relative error (ARE), the sum of the errors squared (ERRSQ/SSE), the sum of the absolute errors (EABS) and Chi-square test (χ2) were used to predict the most optimum kinetic model. Sorbent-sorbate reaction nature was estimated by fitting equilibrium data by non-linear and transformed linear forms of the Langmuir, Freundlich and Redlich-Peterson isotherms and most optimum isothermal model was optimized by comparing linear and non-linear R2 value and non-linear regression error functions. HCl proved most successful eluating agents for sorbed Sr(II) ions. Biosorption characteristics and effectiveness of the process was also confirmed by Fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDX). In view of promising efficiency of peanut husk as an adsorbent, it could possibly be used for the removal of Sr(II) ions from aqueous medium and is also extendable to other radionuclide

Dietary energy level affects adipose depot mass but does not impair in vitro subcutaneous adipose tissue response to short-term insulin and tumor necrosis factor-α challenge in nonlactating, nonpregnant Holstein cows.

We assessed effects of overfeeding energy to nonlactating and nonpregnant Holstein cows during a length of time similar to a typical dry period on body lipid storage and the abundance of genes related to insulin signaling, inflammation, and ubiquitination in subcutaneous adipose tissue (SAT) in vitro challenged with insulin and recombinant bovine tumor necrosis factor-α. Fourteen cows were randomly assigned to either a high-energy (OVE; net energy for lactation = 1.60 Mcal/kg of dry matter; n = 7) or control (CON; net energy for lactation = 1.30 Mcal/kg of dry matter; n = 7) diet for 6 wk. Immediately after slaughter, liver, kidneys, and mammary gland were separated and weighed. The adipose tissue mass in the omental, mesenteric, and perirenal depots was dissected and weighed. Subcutaneous adipose tissue was collected from the tail-head region and was used as follows: control, bovine insulin (INS) at 1 µmol/L, tumor necrosis factor-α at 5 ng/mL (TNF), and their combination. Despite a lack of difference in final body condition score, OVE cows had greater energy intake and were heavier than CON cows. Furthermore, overfeeding led to greater mass of mesenteric and perirenal adipose, liver, and mammary gland. Overall, SAT incubated with INS had an upregulation of insulin receptor (INSR), interleukin-10 (IL10), small ubiquitin-like modifier 3 (SUMO3), and ubiquitin conjugating enzyme E2I (UBC9), whereas TNF upregulated peroxisome proliferator-activated receptor gamma (PPARG), diacylglycerol O-acyltransferase 2 (DGAT2), interleukin-6 (IL6), nuclear factor kappa B subunit 1 (NFKB1), small ubiquitin-like modifier 2 (SUMO2), and UBC9. Regardless of in vitro treatment, feeding OVE upregulated PPARG, fatty acid synthase (FASN), and insulin induced gene 1 (INSIG1). Abundance of PPARG was greater in SAT of OVE cows cultured individually with INS and TNF. The interaction between diet and in vitro treatment revealed that sterol regulatory element binding transcription factor 1 (SREBF1) had greater abundance in SAT from the CON group in response to culture with INS, whereas SAT from OVE cows had greater SREBF1 abundance in response to culture with TNF. The mRNA abundance of IL6 and NFKB1 was greater in response to TNF treatment and overall in CON cows. Furthermore, SAT from these cows had greater IL10 abundance when cultured with INS and TNF. Overall, data highlighted that overfeeding energy increases adipose tissue mass in part by stimulating transcription of key genes associated with insulin signaling, adipogenesis, and lipogenesis. Because SAT thickness or mass was not measured, the lack of effect of overfeeding on body condition score limits its use to predict overall body lipid storage. An overt inflammatory response in SAT after a 6-wk period of over-consumption of energy could not be discerned

Reticulo-rumen mass, epithelium gene expression, and systemic biomarkers of metabolism and inflammation in Holstein dairy cows fed a high-energy diet

Feeding a higher-energy diet by increasing cereal grains at the expense of forage during the last 3 to 4 wk prepartum is a traditional approach to help the rumen "adapt" to the traditional diets fed at the onset of lactation. Increasing grain/concentrate in the diet changes ruminal fermentation and in sheep and goats elicits marked changes in mRNA expression of immune-related genes in ruminal epithelium. Whether such changes at the epithelial and systemic levels occur in dairy cows when the dietary energy content increases at a fixed level of concentrate is unknown. Fourteen nonpregnant, nonlactating Holstein cows were fed a control lower-energy (CON, 1.30 Mcal/kg of dry matter) diet to meet 100% of estimated nutrient requirements for 3 wk, after which half of the cows were assigned to a higher-energy diet (OVE, 1.60 Mcal/kg of dry matter) and half of the cows continued on CON for 6 wk. Levels of forage and concentrate for CON and OVE were 80 and 79% and 20 and 21%, respectively. Plasma samples were collected 1 d before slaughter to examine biomarkers of metabolism, liver function, inflammation, and oxidative stress. The reticulo-rumen mass was recorded at slaughter, and samples of epithelium were harvested from all cows. The expression of 29 genes associated with tight junctions, immune function, and nutrient transport (volatile fatty acids, urea, and trace minerals) was examined. Overfeeding energy led to consistently greater dry matter intake over time, and lowered plasma concentrations of haptoglobin, paraoxonase, bilirubin, fatty acids, and myeloperoxidase (secreted by neutrophils). In contrast, OVE resulted in greater hydroxybutyrate and cholesterol concentrations. A greater reticulo-rumen mass in cows fed OVE did not alter genes associated with tight junctions (CDLN1, CDNL4, OCLN, TJP1), immune function (IL1B, IL10, NFKB1, TLR2, TLR4, TNF), oxidative stress (SOD1, SOD2), or most nutrient transporters. However, feeding OVE upregulated the acute-phase protein SAA3 by 3.5-fold and downregulated a volatile fatty acid transporter (SLC16A1) and a Fe and Cu transporter (SLC11A2). The lack of effect on mRNA expression along with lower plasma concentrations of inflammation biomarkers indicates that long-term intake of a higher-energy diet ad libitum was not detrimental to ruminal epithelium integrity. In that context, a protective function of SAA3 could be envisioned with a role in opsonizing gram-negative bacteria that produce endotoxins. The long-term control of volatile fatty acid absorption and trace minerals from the rumen in cows overfed energy does not seem to be controlled at the gene transcription level. The relevance of these findings to the nutritional management of pregnant dry cows merits further research

Hepatic phosphorylation status of serine/threonine kinase 1, mammalian target of rapamycin signaling proteins, and growth rate in Holstein heifer calves in response to maternal supply of methionine.

The study investigated whether methionine supply during late pregnancy is associated with liver mammalian target of rapamycin (MTOR) pathway phosphorylation, plasma biomarkers, and growth in heifer calves born to cows fed a control diet (CON) or the control diet plus ethylcellulose rumen-protected methionine (MET; 0.09% of dry matter intake) for the last 28 d prepartum. Calves were fed and managed similarly during the first 56 d of age. Plasma was harvested at birth and 2, 7, 21, 42, and 50 d of age and was used for biomarker profiling. Liver biopsies were harvested at 4, 14, 28, and 50 d of age and used for protein expression. Body weight, hip height, hip width, wither height, body length, rectal temperature, fecal score, and respiratory score were measured weekly. Starter intake was measured daily, and average daily gain was calculated during the first 8 wk of age. During the first 7 wk of age, compared with calves in the CON group, calves in the MET group had greater body weight, hip height, wither height, and average daily gain despite similar daily starter intake. Concentration of methionine in plasma was lower at birth but increased markedly at 2 and 7 d of age in MET calves. Plasma insulin, glucose, free fatty acids, and hydroxybutyrate did not differ. A greater ratio of phosphorylated α-serine/threonine kinase (AKT):total AKT protein expression was detected in MET calves, namely due to differences at 4 d of age. The phosphorylated MTOR:total MTOR ratio also was greater in MET calves due to differences at 28 and 50 d (8 d postweaning). The decrease in phosphorylated MTOR:total MTOR between 14 and 28 d in CON calves agreed with the increase in phosphorylated eukaryotic translation initiation factor 4E binding protein 1 (EIF4EBP1):total EIF4EBP1 ratio during the same time frame. The overall expression of phosphorylated ribosomal protein S6 kinase B1 (RPS6KB1):total RPS6KB1 and phosphorylated eukaryotic translation elongation factor 2 (EEF2):total EEF2 was lower in MET calves. Regardless of methionine supply prepartum, there was an 11-fold temporal decrease from 4 to 50 d in phosphorylated AKT:total AKT. Similarly, regardless of methionine supply, there were overall decreases in phosphorylation ratios of AKT, MTOR, RPS6KB1, and eukaryotic translation initiation factor 2A (EIF2A) over time. Data provide evidence of a positive effect of methionine supply during the last month of pregnancy on rates of growth during the first 7 wk of age. Phosphorylation status of some components of the MTOR pathway in neonatal calf liver also was associated with greater maternal supply of methionine. Thus, the data suggest that molecular mechanisms in the liver might be programmed by supply of methionine during late pregnancy. The exact mechanisms coordinating the observed responses remain to be determined

In situ immobilization of CuO on SiO\u3csub\u3e2\u3c/sub\u3e/graphite matrix, modified with benzimidazolium-1-acatate ionic liquid: Application as catechol sensor

© 2017 Carbon ceramic material (SiO2/C) was prepared using the sol-gel technique. Copper oxide was in situ synthesized on the pores of the matrix, to ensure homogenous distribution of the electroactive species in the matrix pores. To enhance the conductivity of material, the SiO2/C/CuO was modified with benzimidazolium-1-acetate ionic liquid. The surface area (SBET 432.56 m2/g) and pore volume (0.90 cm3/g) of the material were calculated from BET analysis. SEM images showed compactness of materials, having no phase segregation within the magnification used. The structure of ionic liquid was confirmed using NMR and FTIR analysis. The electrodes as a pressed disk fabricated from SiO2/C, SiO2/C/CuO, and SiO2/C/CuO/IL materials were tested as an electrochemical sensor for catechol determination. Electrochemical impedance spectroscopy has revealed that the SiO2/C/CuO/IL-based sensor assists the charge transfer owing to electron rich density, resonance, and conductance of ionic liquid structural moiety. SiO2/C/CuO/IL electrode exhibits excellent sensitivity, linear response range and low limit of detection (LOD) of 712 μA μmol− 1 dm3 cm− 2, 0.2 mM–10 mM and 0.7 × 10− 8 mol L− 1, respectively. The sensor was also tested for the determination of catechol in real samples and gives very good results for its determination