In the electrocoagulation process a suspension of kaolinite and bentonite is coagulated by electrochemical treatment where aluminum anodes are dissolved and aluminum ions react with clay particles, forming flocs which precipitate. Several factors affecting the efficiency of electrocoagulation are investigated. They include NaCl concentration, voltage, and flow conditions within the cell. Increased NaCl concentration led to lower electric resistance and cleaner running electrodes. Enhanced shear associated with recirculation resulted in clear supernatant and more compact floes. While increasing the feed rate, which was equivalent to decreasing aluminum concentration through the system, reduced cake height but increased turbidity.

The objective of this study was to observe flocculation of montmorillonite in the presence of a glucose polymer (dextran) and to observe the effect of saturating cation and coagulant addition on the flocculation process. Flocculation of montmorillonite was dependent on polymer molecular weight, polymer/clay ratio (w/w), nature of exchangeable cation, and ionic strength of the suspension to which the polymer was added. The T500 dextran (molecular weight = 5 × 105) caused enhanced sedimentation of Ca-montmorillonite suspension at a polymer/clay ratio of ≤0.01. Increasing the polymer concentration above this level stabilized the suspension such that sedimentation was less than or equal to that of the control. The T2000 dextran (molecular weight = 2 × 106) caused a similar increase in the sedimentation of Ca-montmorillonite at polymer/clay ratios of <0.1. The ability of the T2000 polymer to cause flocculation at greater polymer/clay ratios as compared to the T500 polymer was attributed to the lower osmotic pressure between clay particles for equal concentrations of the two polymers. Flocculation of Ca-montmorillonite by dextran was enhanced when the clay had initially been coagulated by the addition of salt. Reduction of the diffuse double layer upon addition of salt permitted the polymer to extend beyond the electrostatic barrier of the clays. Dextran was not able to flocculate Mg-montmorillonite suspensions with or without the presence of coagulant. The displacement of water molecules at the clay surface rather than within the hydration shell of the more highly polarizing Mg cations by polymer segments resulted in a greater polymer collapse on the clay surface leaving fewer and shorter polymer loops and tails available for contacting adjacent clay particles.

Recent evidence of the occurrence of beidellite in many soils around the world necessitates a better understanding of the role of charge location on the colloidal behavior of this smectite as compared to the more frequently studied montmorillonites. Clay suspension stability and sorption of an organic polymer, two properties sensitive to surface charge characteristics, were selected to examine the differences in colloidal behaviors of these smectites. The Otay montmorillonite was shown to have a higher charge than either the beidellite or the SWy-1 montmorillonite. Even though structural formulae resulted in a higher permanent charge for the beidellite as compared to the SWy-1, effective charge of these two smectites is the same. The pH dependency of the critical coagulation concentration of the smectites could not be explained based only on edge charge considerations, and it is proposed that tetrahedral charge location enhances the pH effect on the CCC. Decreased poly(vinyl) alcohol sorption with either increasing surface charge or tetrahedral charge location was observed. Both parameters affect the ease of replacement of water molecules by PVA on the surface of smectites.

The influence of surfactants on the flow behavior of sodium montmorillonite dispersions (2% w/w) was studied for a cationic (cetylpyridinium chloride, CPCl) and an anionic surfactant (sodium dodecylsulfate, SDS). When the dispersion pHs were >3.5 and <7, CPCl concentrations >10−4 M increased the shear stress but the Bingham yield value remained virtually unchanged (τo ≈ 100 mPa). At pH ≈ 7, the shear stress and yield point decreased with increasing CPCl concentration (τo from 430 to 100 mPa). The flow properties of sodium calcium bentonite dispersions were independent of pH and CPCl concentrations ≤ 10−4 M; they increased modestly at higher concentrations. At pH < 4, SDS addition to the sodium montmorillonite dispersions increased the shear stress and yield value to a maximum value (τo = 2100 mPa) at 10−3 M SDS; higher SDS concentrations reduced the shear stress and yield value. At pH > 4, the flow values decreased to a minimum value at 10−2 M SDS (τo from 430 to 50 mPa). The flow of the sodium calcium bentonite dispersions at pH > 4 was independent of SDS concentrations ≤ 10−3 mole/liter; at higher SDS concentrations, the flow values increased more strongly in sodium calcium bentonite than in sodium montmorillonite dispersions.

Surfactants influence the flow behavior of sodium montmorillonite dispersions by their action on the card-house networks in strongly acidic medium and, at higher pH, by the electroviscous effect. At the highest surfactant concentrations without flocculation, the shear stress and yield value are increased by interacting chains of opposed particles.

Addition of the surfactants increases the salt (NaCl) stability of the dispersions because the adsorbed surface active agents influence the counterion distribution between the Stern and the diffuse ionic layer.

Kaolinite is a common gangue mineral in iron ore and sodium silicate has been used widely as a dispersant of silicate gangue minerals including kaolinite in various iron-ore flotation methods over a wide range of pH. Its actual dispersive effect on kaolinite under iron-ore flotation conditions has received very limited attention, however. The presence of hydrolyzable metal cations in process water further complicates sodium silicate—kaolinite interactions. In the present study, the dispersive effect of sodium silicate on kaolinite particles in distilled water as well as in CaCl2 and MgCl2 solutions was investigated systematically through electrophoretic mobility and colloid-stability studies. The studies were based on controlled pH, which eliminated the dispersive effect of sodium silicate induced by increasingpulp pH, in order to simulate the conditions of iron-ore processing. With pH controlled at constant levels, sodium silicate dispersed kaolinite only when positively charged sites were present on kaolinite surfaces and the zeta potential of kaolinite was more negative than ~−30 mV. Over the pH range from 5 to 10.5, a significant dispersive effect of sodium silicate was only observed at pH 7. In process water, when Ca and Mgwere present, the strong coagulation of kaolinite particles caused by the hydrolyzable metal cations could not be dispersed effectively with sodium silicate.

Freshwater has become increasingly scarce in many countries. To reduce the consumption of freshwater, the use of saline water resources in industry could provide an opportunity to meet the challenge of water-supply sustainability. However, the presence of electrolytes in saline water causes the coagulation of kaolinite, the colloid stability of which plays a key role in the processing of a number of minerals. Therefore, the dispersion of kaolinite in saline water was studied here. Electrophoretic mobility and colloid stability studies were conducted on a sodium hexametaphosphate-kaolinite system in the presence of NaCl, KCl, CaCl2, and MgCl2, the major electrolytes in saline water resources. The effect of each electrolyte on kaolinite dispersion was studied. Based on the studies of individual electrolytes, a method was developed to disperse kaolinite in 1:1 diluted synthetic seawater with distilled water, which may potentially reduce the consumption of freshwater by 50% when applied in industry.

Global weak solutions to the continuous Smoluchowski coagulation equation (SCE) are constructed for coagulation kernels featuring an algebraic singularity for small volumes and growing linearly for large volumes, thereby extending previous results obtained in Norris (1999) and Cueto Camejo & Warnecke (2015). In particular, linear growth at infinity of the coagulation kernel is included and the initial condition may have an infinite second moment. Furthermore, all weak solutions (in a suitable sense) including the ones constructed herein are shown to be mass-conserving, a property which was proved in Norris (1999) under stronger assumptions. The existence proof relies on a weak compactness method in L1 and a by-product of the analysis is that both conservative and non-conservative approximations to the SCE lead to weak solutions which are then mass-conserving.

Poly(ethylene oxides) (PEOs) with sulphonate groups attached at both chain ends (S-PEOs) were strongly adsorbed by dispersed Na- and Ca-montmorillonite particles. The amounts adsorbed were very similar to those of cationic end-capped poly(ethylene oxides). In both cases bilayers of PEO chains were intercalated so that the basal spacing of the particles reached the same plateau values of ~1.73 nm. In contrast, the influence of anionic PEOs on the colloidal behaviour of the Na- and Ca-montmorillonite dispersions was very different from the effect of the cationic PEOs. The shorter chain S-PEOs (S-PEO 1500, 4000) destabilized the Na-montmorillonite dispersions by coagulation due to the Na+ ions introduced as counterions to the S-PEOs. The longer chain S-PEO 20000 and S-PEO 35000 did not coagulate the Na-montmorillonite sols because the corresponding Na+ concentration did not reach the critical coagulation value. The slightly enhanced salt tolerance indicated that the long-chain PEOs exerted a weak steric stabilization. In contrast, bridging of the particles by S-PEO molecules and Ca2+ ions played an important role in destabilizing the Ca-montmorillonite dispersions in the form of flocs and formation of gels.

The colloidal state (sol, flocs, gels) of Na-montmorillonite dispersions (from bentonite from Bavaria, Germany) was adjusted by the addition of poly(ethylene oxides) with terminal trimethylammonium groups. The colloidal state of the dispersions changed with the molar mass of these end-capped poly(ethylene oxides). The sol-gel diagrams (up to 4.5% (w/w) montmorillonite) in the presence of TMA-PEO 1500 and TMA-PEO 4000 (up to 40 g/l) were characterized by large fields of gel whereas TMA-PEO 20000 and TMA-PEO 35000 caused peptization by steric stabilization. Even dispersions with the highest montmorillonite content (4.5%) were peptized by >0.2 g/l TMA-PEO 35000. The critical coagulation concentration of NaCl was increased by the polymer addition, but the increase was modest (from 8-12 mmol/l to 50 mmol/l). The changes of the colloidal state, the flow behaviour and the salt coagulation reveal the sensitive interplay between stabilization mechanisms (electrostatic, steric) and destabilization effects (bridging, charge compensation, depletion flocculation).

We examined the latent structure of 26 cheese related phenotypes in dairy cattle. Traits related to milk yield and quality (8 traits), milk protein fractions (8 traits), coagulation and curd firmness indicators (CF, 5 traits) and cheese-making phenotypes (cheese yields (%CY) and nutrient recoveries in the curd (REC), 5 traits) were analysed through multivariate factor analysis (MFA) using a varimax rotation. All phenotypes were measured in 1264 Brown Swiss cows. Ten mutual orthogonal, latent variables (factors; Fs) were obtained explaining 74% of the original variability. These Fs captured basic concepts of the cheese-making process. More precisely, the first 4 Fs, sorted by variance explained, were able to capture the underlying structure of the CY percentage (F1: %CY), the CF process with time (F2: CFt), the milk and solids yield (F3: Yield) and the presence of nitrogen (N) in the cheese (F4: Cheese N). Moreover, 4 Fs (F5: as1-β-CN, F7: κ-β-CN, F8: as2-CN and F9: as1-CN-Ph) were related to the basic milk caseins and 1 factor was associated with the α-LA whey protein (F10: α-LA). A factor describing udder health status (F6: Udder health), mainly loaded on lactose, other nitrogen compounds in the milk and SCS, was also obtained. Further, we inferred the effects of some potential sources of variation (e.g. stage of lactation and parity) including feeding and management systems. Stage of lactation had a significant effect for 7 of the 10 Fs, followed by parity of the cow (3 Fs), dairy system and feeding (3 Fs). Our work demonstrates the usefulness of MFA in reducing a large number of variables to a few latent factors with biological meaning and representing groups of traits that describe a complex process like cheese-making. Such an approach would be a valuable tool for studying the influence of different production environments and individual animal factors on protein composition and cheese-making related traits.

The physical properties of rennet-induced coagulation of preheated camel and cow milk gels (50 and 70 °C for 10 min) enriched with calcium chloride (CaCl2) and hydrogen phosphate dihydrate (Na2HPO42H2O) were evaluated using the dynamic low amplitude oscillatory shear analysis. The storage modulus (Gʹ) and loss modulus (Gʺ) of camel milk gels showed significant (P < 0·05) lower values than those of cow milk gels. The preheating of camel milk at 50 °C affected negatively the gelation properties, while the preheating at 70 °C prevented the formation of rennet-induced milk gels. No effect was observed on the gelation properties of cow milk gels. The CaCl2 added at 10 and 20 mM to preheated camel and cow milk reduced significantly (P < 0·05) the gelation time and increased the gel firmness. In contrast, Na2HPO42H2O added at 10 and 20 mM induced the formation of weak gels for preheated camel and cow milk at 50 °C, and even no gelation for preheated camel milk at 70 °C.

Introduction: In light of escalating health care costs, initiatives such as Choosing Wisely have been advocating the need to “reduce unnecessary or wasteful medical tests, treatments and procedures”. We have identified coagulation studies as one of those low cost, but frequently ordered items, where we can decrease unnecessary testing and costs by leveraging our Computerized Practitioner Order Entry (CPOE). Considerable evidence exists to suggest a low yield of doing coagulation studies (herein defined as PTT AND INR’s) in suspected cardiac chest pain patients (SCCP). Methods: Using administrative data merged with CPOE we extracted data 90 days pre- and 90 post-intervention (Pre-intervention: May 20, 2015 to August 19th 2015, Post-intervention: August 20th, 2015 to November 18th 2015). The setting for the study is a large urban center (4 adult ED’s with an annual census of over 320,000 visits per year). Our CPOE system is fully integrated into the ED patient care. The intervention involved modifying the nursing CPOE to remove the pre-selected coagulation studies in SCCP and providing education around appropriate usage of coagulation studies. Patients were included in the study if the bedside nurse or physician felt 1. the chest pain may be cardiac in nature and 2. Labs were ordered. The primary outcome was to compare the number of coagulation studies ordered pre and post-intervention. Results: Our analysis included 10,776 patients that were included in an SCCP pathway as determined by the CPOE database. Total number of visits in these two phases were similar (73,551 pre and 72, 769 post). In the pre-intervention phase, 5255 coagulation studies were done (4246 ordered by nursing staff and 1009 studies ordered by ED physicians). In the post-intervention phase, 1464 coagulation studies were ordered (1211 by nursing staff and 253 additional tests were ordered by ED physicians). With our intervention, we identified a net reduction of 3791 coagulation studies in our post-intervention phase for a reduction of 72.14% reduction (p=<0.0001) At a cost of 15.00$ (CDN$ at our center), we would realize an estimated cost -savings of 56,865$ for this intervention over a 90 day period. Conclusion: We have implemented a simple, sustainable, evidence based intervention that significantly minimizes the use of unnecessary coagulation studies in patients presenting with SCCP.