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Hamstring injuries are very common in field sports. Muscle architecture has been suggested as a risk factor for hamstring strain injury. Various medical imaging techniques (Magnetic Resonance Imaging and Ultrasound) have been developed to assess muscle architecture. Ultrasound is often used to assess in vivo hamstring muscle architecture. The relationship player load (match-play, training, strength & conditioning programme) and hamstring muscle architectural characteristics at the mid-season and end of season time points will be evaluated to determine the extent to which extrinsic factors influence hamstring muscle architecture

Hamstring injuries carry a high injury burden and are more prevalent in males than females. This study is designed as a cross-sectional study with two groups. Forty elite rugby union players (20 males; 20 females) will have their hamstring muscle architecture (fascicle length, pennation angle and muscle thickness) measured using B-mode ultrasound. Muscle architecture is a modifiable risk factor associated with hamstring injuries. The aim of this study will be to determine whether differences exist in the hamstring muscles (Bicep Femoris long head, Bicep Femoris short head, Semitendinosus and Semimembranosus) architectural characteristics of elite- level male and female rugby union players.

Hamstring strains are the most prevalent injury sustained by field-sport athletes. Insufficiencies in the architectural characteristics of the hamstring muscles can heighten an athlete’s risk of incurring a hamstring strain. To evaluate the influence of hamstring muscle architectural characteristics (i.e., fascicle length, pennation angle, muscle thickness) on injury risk, it is necessary to precisely evaluate these characteristics. Considering this, our aim was to develop and evaluate the precision of a novel semi-automated tracing software to measure the architectural characteristics of the biceps femoris long head (the most commonly injured hamstring muscle) in B-mode ultrasound images.We acquired static sonograms of the biceps femoris long head from ten healthy male field-sport athletes. The architectural characteristics (fascicle length, pennation angle and muscle thickness) of participants’ biceps femoris long head were evaluated 10 times using the tracing software, with the specific purpose of determining its measurement precision.

Hamstring injuries are very common in field sports. Muscle architecture has been suggested as a risk factor for hamstring strain injury. Various medical imaging techniques (Magnetic Resonance Imaging and Ultrasound) have been developed to assess muscle architecture. Ultrasound is often used to assess in vivo hamstring muscle architecture. The architecture of the hamstring muscles often extends outside the ultrasounds field of view. Previous ultrasound techniques used often generate questionable results. This study aims to describe the reliability of large field of view ultrasound and test – retest minimum detectable difference of the hamstring muscles

Background Particle breakage deteriorates dairy powder properties and it easily takes place in many processes. However, there currently is a lack of research on dairy powder breakage for understanding and controlling it. The research on particle breakage in other industries is very extensive and thorough, and could act as good reference knowledge for dairy powder breakage research, but at this time there is no review of this useful information. Scope and approach Based on the research done in dairy powder breakage and findings of particle breakage studies of other industries relevant to dairy powder particle properties, this review includes the breakage mechanisms of dairy powders, methods suitable for studying dairy powder breakage, the influence of breakage on powder properties, and influencing factors of dairy powder breakage which also can be considered as controlling factors. Key findings and conclusions Powder breakage significantly affects dairy powder physical properties which in-turn influence powder functionalities, especially the rehydration properties. The extent of agglomerates breakage corresponds to different breakage mechanisms which result in different final particle sizes and particle size distributions. The processing conditions (such as the parameters during dry-mixing, vibration, and pneumatic conveying) and the characteristics of particles (including physical properties and composition) are two main influencing factors that can be considered to control dairy powder breakage. However, there is currently not enough study showing which factors are more effective in controlling breakage. Some single-particle or multi-particle tests can be used to investigate dairy powder breakage and further research on the effectiveness of those controlling factors should be done.

As a powder wets and dissolves in a liquid, trapped gas bubbles are released and the measurement of the evolution of gas volume versus time can be used to quantify the ease with which powder wets and dissolves in the liquid. This phenomenon forms the basis of the BARDS analytical measurement technique. To complement this experimental approach, a model of the evolution of gas bubbles from a powder into a liquid during powder dispersion and solubilisation is presented. The model is validated against experimental data from the rehydration of Milk Protein Isolate (MPI) powder; both in its original state, and in the agglomerated state and is shown to match the experimental data with good accuracy. Use of the model facilitates a fuller interpretation of the experimental BARDS data and the values of dispersion and solubilisation rate constants can be applied for quantitatively comparing the behaviour of powders. It also permits development of robust rehydration parameters from the experimental BARDS signal.

This paper presents a novel approach to the determination of the coalescence kernel for population balance modelling of a general class of batch fluidised bed aggregation systems, using a continuous sprayed-in liquid binder. Coalescence requires inter-particle collisions, the wetting of the contact surfaces and the dissipation of particle kinetic energy by the viscous squeezing of the binder film. These three sub-processes in principle depend both on the size of the contacting particles and on time. A new time-dependent aggregation rate constant of the coalescence kernel has been formulated by considering the general evolution of inter-particle collision behaviour with time. The model is implemented in MATLAB and its numerical output compared to two sets of experimental data: the granulation of glass beads with polyethylene glycol as a binder and the granulation of semolina with water. The evolution of mean and standard deviation in diameter versus time are examined as is the state of the size distribution at different stages in the process. The time-averaged aggregation rate for the glass beads evaluated as 7.59 × 10−9 m-0.5 s−1 while for the semolina it was 3.86 × 10−9 m-0.5 s−1. The agreement between numerical predictions and experiment is shown to be good, demonstrating the validity of the approach. Whilst conceptually simple, the model generates realistic output and provides a powerful insight into the underlying mechanisms of granulation.

Breakage of dairy powder during pneumatic conveying negatively affects the end-customer properties (scoop uniformity and reconstitution). A dilute phase pneumatic conveying system was built to conduct studies into this problem using whey protein isolate powder (WPI) as the test material. Effects of conveying air velocity (V), solid loading rate (SL), pipe bend radius (D), and initial particle size (d) on the level of attrition were experimentally studied. Four quality characteristics were measured before and after conveying: particle size distribution, tapped bulk density, flowability, and wettability. The damaged WPI agglomerates after conveying give rise to many porous holes exposed to the interstitial air. V is the most important input variable and breakage levels rise rapidly at higher airspeeds. The mean volume diameter D[4,3] decreased by around 20% using the largest airspeed of 30 m/s. Powder breakage is also very sensitive to particle size. There appears to be a threshold size below which breakage is almost negligible. By contrast, SL and D show lesser influence on powder breakage. Reflecting the changes in particle size due to breakage, tapped bulk density increases whereas wettability decreases as a result of an increase in conveying air velocity. However, breakage does not show a significant effect on powder flowability as powder damage not only decreases particle size but also changes the particle’s surface morphology.

This study explored the effect of protein content (whey protein and casein) and carbohydrate content (lactose, sucrose, and maltodextrin) on the breakage behaviour and its influence on spray-dried agglomerated model infant milk formula. Whey protein powders were bigger in particle size, weaker in structural strength, and marginally more irregular in shape, which resulted in better rehydration properties but more breakage than pure casein powders. Similarly, sucrose samples had better rehydration properties and higher glass transition temperatures but suffered more breakage than maltodextrin and pure lactose powders because of their bigger particle size. The influence of proteins on breakage was greater than that of carbohydrates. Breakage changed the physical and structural properties of powders, especially for whey protein and sucrose samples, which caused the deterioration of rehydration properties and the decrease in crystallization temperatures. From the perspective of particle breakage, unwanted dairy powder breakage could be controlled by changing powder formulations.

In this work, the strength of tablets made from mixtures of whey protein concentrate (WPC) powder and different types of sugar was investigated. The agglomerated WPC powder was pneumatically conveyed (lean phase) at three different air speeds of 10, 20 or 30 m/s to simulate the effects of industrial powder transport, resulting in agglomerates with reduced integrity. Conveyed and control WPC powder, and sugar of three different particle size distributions (i.e., granulated, GS; caster, CS and icing sugar, IS) were analysed for microstructure, particle size, moisture, and flowability. Tensile strength of tablets from WPC powder alone or blended with 0.5–10% sugar was tested. Conveying of WPC powder led to a significant increase in tablet strength, (i.e., from failure strength of 1.67 N/mm2 for control tablets to 2.33, 2.11 and 2.11 N/mm2 after conveying at 10, 20 or 30 m/s, respectively), suggesting that the generation of smaller powder particles led to increased mechanical strength of tablets. The addition of sugar also resulted in a significant increase in tablet strength (e.g., failure strength of 2.34, 2.12 and 2.47 N/mm2 at 1.5% addition level of GS, CS and IS, respectively) and strongest tablets were obtained at 1.5–3% sugar addition and by blending with icing sugar. This study demonstrated, for the first time, that conveying and dry blending of whey protein and sugar powders significantly influenced the rheological properties of resultant tablets.

Purpose To assess the intra-rater reliability of static wide field of view ultrasound to quantify the architectural characteristics of the hamstring muscles. Methods Twenty amateur male athletes were recruited. Their left hamstring muscles were assessed using static wide field of view ultrasound on two separate occasions. Static ultrasound images were acquired by a single sonographer using a 92mm linear transducer. The architectural characteristics (muscle length, fascicle length, pennation angle and muscle thickness) from two distinct locations of the bicep femoris long head and semimembranosus were evaluated. Muscle length and thickness of the bicep femoris short head and semitendinosus muscle were also evaluated. Intraclass correlation coefficient analyses were performed to determine the intra-rater reliability of the performed measurements. Results Both muscle (intraclass correlation coefficient = 0.99; standard error of measurement = 4.3 to 6.6mm) and fascicle (intraclass correlation coefficient = 0.92 to 0.98; standard error measurement = 1.1 to 2.4mm) length were measured with excellent intra-rater reliability. Muscle thickness was measured with excellent reliability (intraclass correlation coefficient = 0.9 to 0.96; standard error of measurement = 0.91mm to 1.4mm) for all hamstring muscles except for the proximal segments of the bicep femoris short head (intraclass correlation coefficient = 0.85; standard error of measurement = 0.84mm) and semitendinosus (intraclass correlation coefficient = 0.88; standard error of measurement = 0.82mm), which were measured with good reliability. Pennation angle was measured with good reliability (intraclass correlation coefficient = 0.77 to 0.87; standard error of measurement = 1 to 1.6°). Conclusion The architectural characteristics of the hamstring muscles of male amateur athletes can be reliably quantified using static wide field of view ultrasound.

Hamstring strains are the most prevalent injury sustained by field-sport athletes. Insufficiencies in the architectural characteristics of the hamstring muscles can heighten an athlete’s risk of incurring a hamstring strain. To evaluate the influence of hamstring muscle architectural characteristics (i. e., fascicle length, pennation angle, muscle thickness) on injury risk, it is necessary to precisely evaluate these characteristics. Considering this, our aim was to develop and evaluate the precision of a novel semi-automated tracing software to measure the architectural characteristics of the biceps femoris long head (the most commonly injured hamstring muscle) in B-mode ultrasound images. We acquired static sonograms of the biceps femoris long head from ten healthy male field-sport athletes. The architectural characteristics (fascicle length, pennation angle, and muscle thickness) of participants’ biceps femoris long head were evaluated 10 times using the tracing software, with the specific purpose of determining its measurement precision. The tracing software precisely measured the architectural characteristics of the participants’ biceps femoris long head: fascicle length (% CV: 0.64–1.12), pennation angle (% CV: 2.58–10.70), muscle thickness (% CV: 0.48–2.04) Our semi-automated skeletal muscle tracing algorithm precisely measures fascicle length, pennation angles, and muscle thickness of the biceps femoris long head in static B-mode ultrasound images.

Dairy-based powder had considerable development in the recent decade. Meanwhile, the increased variety of dairy-based powder led to the complex difficulties of rehydrating dairy-based powder, which could be the poor wetting or dissolution of powder. To solve these various difficulties, previous studies investigated the rehydration of powder by mechanical and chemical methods on facilitating rehydration, while strategies were designed to improve the rate-limiting rehydration steps of different powder. In this review, special emphasis is paid to the surface and structure of the dairy-based powder, which was accountable for understanding rehydration and the rate-limiting step. Besides, the advantage and disadvantage of methods employed in rehydration were described and compared. The achievement of the powder functionality was finally discussed and correlated with the rehydration methods. It was found that the surface and structure of dairy-based powder were decided by the components and production of powder. Post-drying methods like agglomeration and coating can tailor the surface and structure of powder afterwards to obtain better rehydration. The merit of the mechanical method is that it can be applied to rehydrate dairy-based powder without any addition of chemicals. Regarding chemical methods, calcium chelation is proved to be an effective chemical in rehydration casein-based powder.

Granular particles can be induced to move against gravity upwards through a pipe or tube that is partially inserted under the powder free surface while subject to vertical vibration. This offers a new approach for transporting bulk material. In this paper, the effects of both vibration parameters and insertion depth of a pipe on particle motion are experimentally studied. A minimum vibration amplitude (A) and frequency (f) are necessary for particle motion to occur. There is a monotonic increase of the final rise height of the powder (heq) with increasing amplitude A. However, heq exhibits a non-monotonic dependence on frequency, f. There is an optimum frequency at which particles climb highest, and any further increase of frequency leads to a diminishment of this upwards motion. A phase diagram of particle movement is presented which shows that different zones of motion exist. This unique finding suggests that the mechanism of particle movement is caused by the creation and filling of voids under the tube. Particles cannot move upwards when the pipe insertion depth, hin is PACS number: 45.70.MG - granular flow

Dairy powder breakage occurs in many processes and deteriorates powder properties and functionalities. This study investigated the influence of powder and particle characteristics on the dynamic breakage of dairy powders during the dispersion and conveying in a powder venturi feeder to provide information on assessing and reducing powder breakage during production and transportation. Four kinds of dairy powders (fifteen samples) were analysed: lactose crystals, agglomerates, commercial and lab-scale non-agglomerates. During the dispersion and conveying, breakage degree increased with increasing particle size and decreasing particle structural strength. Considering particle structure, the strength of crystals was the highest, followed by the continuum solids, followed by particles with numerous small holes throughout the particle, followed by particles with a small number of randomly distributed internal holes, followed by the hollow sphere particle with a very thin shell. The breakage behaviour of crystals during conveying was different from the other powders due to the difference in particle structures. Besides, the fat in particles might decrease the breakage of powders.

The granulation step determines the production yield and the final characteristics of the agglomerated couscous grains of durum wheat. The objective of the present work was to explore the capability of the fluidised bed technology to produce agglomerates of durum wheat semolina. The impacts of different processing conditions have been investigated on the structure and functional properties of the agglomerates. The size, shape, water content, compactness, and mechanical strength of the granules were measured. The fluidized bed agglomeration process has been found to produce agglomerates of durum wheat with different attributes compared to those produced by granulation using the low shear mixers. The results were discussed in regard to the hydro-textural approach, in order to get a better understanding of the mechanisms and relationships between process, structure, and properties. Two major agglomeration mechanisms contribute to the growth of the wet agglomerates: a fractal-structuring process followed by a phenomenon of densification. By studying the evolution of the compactness, diameter and water content, it was demonstrated that inter granular arrangements led to an expansion followed by a densification of the wet agglomerates. A relationship was proposed to describe the growth using a fluidized bed of the wet agglomerates of durum wheat semolina.

The effect of lecithin addition on the wettability of whey protein isolate (WPI) powders was investigated in this study. Different concentrations of lecithin solution (0.5%, 2% and 5% w/v) were added by fluidised bed agglomeration and Wurster coating processes. The formed WPI powders, with different particle sizes, were used to compare the densities, porosity and shapes properties, as well as the wetting behaviours, including wetting time, contact angles, water absorption by capillary flow and the strength of films formed at the powder/water interfaces. It was found that, if lecithin was used as bridges to adhere primary particle in agglomeration, the formed granules had large particle size, lower bulk density, higher porosity and more irregular shapes. The influences of the coating process on these properties were shown to be less significant, as lecithin was layered on the outside of the particle surfaces. Those physical and structural modifications in WPI powders caused the improvements in the wettability by different degrees. High coverage of lecithin by coating process gave the particles a more advantageous first step of wetting, showing smaller initial contact angles and weaker protein films; while the porous structures by agglomeration process resulted in quicker water penetration by capillary flow. They were both rate-controlling factors for wetting process, as the limited contribution was found if only controlled by any one of these factors. Consequently, high coverage of lecithin, high porosity of particles and large particle sizes were all necessary for enhancing the wetting behaviours of WPI powders.

Cracks or checks in biscuits weaken the material and cause the product to break at low load levels that are perceived as injurious to product quality. In this work, the structural response of circular digestive biscuits, with diameter 72 mm and thickness 7.2 mm, simply supported around the circumference and loaded by a central concentrated force was investigated by experiment and theory. Tests were conducted to quantify the distribution in breakage strength for structurally sound biscuits, biscuits with natural checks and biscuits with a single known part-through crack. For sound biscuits the breakage force is Normally distributed with a mean of 12.5 N and standard deviation of 1.2 N. For biscuits with checks, the corresponding statistics are 9.6 N ± 2.62 N respectively. The presence of a crack weakens the biscuit and strength, as measured by breakage force falls almost linearly with crack length and crack depth. The orientation of the crack, whether radial or tangential, and its location (i.e. position of the crack mid-point on the biscuit surface) are also important. Deep, radial, cracks located close to the biscuit centre can reduce the strength by up to 50%. Two separate failure criteria were examined for sound and cracked biscuits respectively. The results from these tests were in good accord with theory. For a biscuit without defects, breakage occurred when maximum biscuit stress reached or exceeded the failure stress of 420 kPa. For a biscuit with cracks, breakage occurred as above or alternatively when its critical stress intensity factor of 18 kPam 0.5 was reached.

New-onset diabetes after transplant (NODAT) confers risk of diabetes-related complications as well as a threat to graft function and overall patient survival. The reported incidence of NODAT varies from 14 to 37% in renal transplant recipients worldwide; however, NODAT is yet to be studied in the Irish renal transplant population. Primary aims of this project were to estimate the incidence, to determine associated risk factors and to assess the long-term consequences of NODAT on graft survival and patient survival in the Irish renal transplant population. Retrospective data collection of 415 renal transplant recipients over a 12-year period was performed to record presence of NODAT, patient characteristics and perioperative management. Preoperative screening was reviewed in a subgroup of patients to determine concordance with the International Consensus Guidelines. Statistical analysis was performed using Kaplan-Meier survival functions estimating NODAT detection over time, graft and patient survival. Risk factor association was determined using Cox proportional-hazards models. NODAT incidence was 10.2% in the first 5 years of post-transplant. Risk factors for developing NODAT were recipient age and body weight. Risk of NODAT was highest in the first year of post-transplant and conferred decreased patient survival; however, it did not significantly affect graft survival. Only seven patients of a subgroup of 21 patients who developed NODAT had preoperative testing for diabetes. NODAT incidence in the Irish renal transplant population is slightly below international figures. This project has highlighted current deficits in the national transplant guidelines for the detection of NODAT and NODAT-related risk factors.

Rehydration of milk protein isolate (MPI) powder in water is poor which requires more than 24 h, however it is greatly influenced by solution pH. This study analysed the rehydration of MPI powder in acidic solution followed by neutralization (CN), and in alkalized solution followed by neutralization (NC), and how these pH adjustments impact the dissolution ability and functionality of the MPI. Besides, C’N’ and N’C’ are prepared by the above neutralization sequence with increasing rehydration time. Acid gelation was chosen as an example of critical functional properties. The results showed that applying alkalization (performed by Na-carbonate) as the first step prior to neutralization was superior to acidification (using citric acid) in terms of both dissolution and gelation. MPI powder rehydrated in distilled water gelled very poorly, and this was due to slow dissolution, while neutralized MPI (CN, C’N’, NC and N’C’) produced much stronger gels, in-part due to rapid dissolution and disrupted casein micelle. NC and N’C’ exhibited better gelation characteristics than CN and C’N’ overall, showing much higher elasticity values and earlier gelation point. These were also compared with the rehydration of sodium caseinate, which displayed more rapid dissolution and consequently faster gelation; however, the gelation characteristics became similar to NC over time. N’C’ with longer rehydration time could display further improved gelation characteristics owning higher elasticity than that of SC and SC’. In addition, the neutralized MPI was able to tolerate over-acidification during the acid gelation process.

Dairy powder breakage occurs in many processes and causes deterioration in powder properties but there is currently no research presented in the literature on dairy powder breakage behaviour. The breakage behaviour and the effect of powder properties of an infant milk formula and its sieved size fractions were investigated during three processing methods (powder venturi feeder, lab-scale dilute phase pneumatic conveyor, and laboratory high-speed mixer) based on the changes of particle size distributions (PSD) before and after breakage. Particle size influenced other properties and the breakage behaviour of powders. Four breakage mechanisms were found, dispersion, chipping, disintegration, and splitting, corresponding to the increasing degree of breakage. More intense processing conditions were needed to cause the same breakage mechanism for smaller-sized particles because of their higher powder strength. The breakage of samples with wide PSD often displayed a combination of breakage mechanisms due to the influence of particle size on breakage behaviour.

The effects of fluidised bed (FB) and high shear mixer (HS) granulation processes on water adsorption and flow properties of milk protein isolate powder (MPI) were investigated and compared. The agglomerated granules were characterised by different size fractions. It was found that granules produced from the HS process adsorbed less moisture, with slower adsorption kinetics, compared to those produced from using the FB. Granulation reduced the cohesiveness of the MPI powder, with HS having a significant greater impact due to the formation of the particles with higher bulk density and larger size. Particle size played a critical role that influenced water adsorption and flowability. Granulation processes contributed to different degrees to reducing the minimum outlet diameters of hoppers based on either mass-flow or core-flow discharges. HS granules had large wall friction angles, suggesting a need for steeper hopper walls for effective discharge.

The effects of granule growth in high shear granulation on the structures and rehydration abilities of milk protein powders were investigated. In this study, milk protein isolate, as a model powder, was agglomerated in a high shear granulator. The formed granules with different sizes were used to compare the densities, granule shapes and subsequently the wettability, dispersibility and solubility. It is found that the small nuclei showed the most compacted structures. Then the primary agglomerates coalesced to create irregular secondary structures with lower density and higher porosity until the final agglomerates formed. The densely packed structures allowed the granules to be more easily wetted by water. The large granules showed quicker release of materials into water until reaching a critical size, where more mechanical energy is potentially required for further granule break down. All the agglomerated MPI granules solubilised much more slowly than the standard MPI powder.

In co-melt granulation, collisions occur between the particles to be agglomerated and the binder material. Depending on the stage of granulation, the binder material can be in the solid or liquid phase. The outcome of these collisions controls the dynamics of the granulation process and the fundamental physics of the impacts are of interest. This paper examines the impact of glass beads (model particles) and solid Poly Ethylene Glycol (PEG) flakes on a substrate of PEG as the temperature of the PEG layer is increased from below its melting point to above it. While the layer is in the solid state, the result of the impact can be quantified by the coefficient of restitution. When the layer is in the liquid state, the impact can be quantified by the immersion behaviour. The results obtained show that the coefficient of restitution between either glass beads and PEG flakes and the PEG layer is strongly affected by temperatures. As the PEG layer approaches its melting point, the coefficient of restitution falls to zero. Once the temperature of the PEG layer exceeds the melting point, the impact is characterised by a transient maximum indentation and then rebound to an equilibrium position. These too are strongly dependent on temperature.

Rehydration is an important powder property and is regarded as a critical issue by the dairy industry. Traditional powder rehydration measurements are relatively empirical with poor reproducibility. Thus, more reliable techniques tailored for dairy powders should be developed based on varied rehydration behaviours and applications. In this paper, a critical assessment to identify the measurement characteristics of milk protein powder rehydration is presented. Milk protein based powders were used as model systems. Four different wettability measurements (Immersion, Capillary rise, Condensation and Spreading) and four different dispersibility measurements (Dispersibility Index, Light scattering of particles in suspension, Light transmission and Conductivity of suspension) are compared and analysed. The results show that the method based on immersional wetting procedure is only appropriate for skimmed milk powder while the method for capillary rise wetting is more useful for the agglomerated milk protein powders with porous structures. Contact angle changes in the spreading wetting approach is found to be a straightforward technique to show the hydrophobicity or hydrophilicity of milk protein powders. If compared with traditional dispersibility measurements, light transmission of suspension is suitable to reflect optical properties of slow dispersion process. Light scattering methods can also be used to measure the dynamic size change of particles during the dispersion process. Furthermore, the conductivity of suspensions is a useful indicator to quantify the dispersibility indirectly by the release of minerals during rehydration. In summary, it is necessary to understand the specialities and applications of dairy powders before choosing the appropriate rehydration measurement methods.

Rehydration in an alkaline solution has been shown to improve the rehydration behaviour of milk protein isolate (MPI). In this study, the focus is on citric acid neutralization of MPI powder dissolved in alkaline solution. The results showed that alkalization induced more negative zeta-potential compared to MPI control, reducing it from –22.4 mV to –32.6 mV. Neutralization had a relatively similar zeta-potential value as alkalized sample. Sodium carbonate addition increased pH and caused a consequential reduction of ionic calcium in aqueous phase and, neutralization caused a small increase in ionic calcium. Soluble aggregate of κ-casein protein and whey protein was suggested in alkalization and neutralization process by non-reducing SDS-PAGE. In addition, neutralization kept a stable colloidal particle size for pHs decreased to pH 9,8 and 7; however, alkalization and neutralization created casein aggregates of larger colloidal particle size than primary casein micelle in control MPI.

Dairy powder breakage has always occurred during production and transportation though few studies on it have been published. This paper examines the breakage of infant formula using three different processing methods (laboratory high-speed mixing, lab-scale pneumatic conveying, and factory-scale blending) and the effect of breakage on powder properties. In both mixing and high-velocity pneumatic conveying, particles were broken into smaller entities and the particle size of samples significantly decreased. Particle breakage was accompanied by a significant decrease in porosity and increase in density and surface free fat. This in-turn decreased the rehydration properties of samples, especially for high-speed mixing, while breakage had only a small influence on powder flowability. By contrast, some agglomeration occurred during blending for short time in the blender and the particle size did not decrease (P > 0.05) even for blending at longer time, thus, there were only minor impacts on physical and functional properties of powders.

Particles can move against gravity inside a vibrating tube inserted in a static granular bed. This offers a new approach for transporting bulk material. In this work, we demonstrate a method to enhance the conveying of powder by sealing the tube top. With the same vibration conditions, a comparison of particle motion in an opened tube and closed top (sealed) pipe is made. Compared to an un-sealed pipe, particle upward motion within a sealed pipe is improved. With low vibration strength, only particles in the sealed tube can ascend. With increasing vibration strength, particles can climb in both tubes while particles in sealed pipe move faster and higher. The enhancement effect works well for particles of smaller size (d

This paper proposes the design of a wholly mechanical constant-force gripper that can accommodate the imprecise manipulation of brittle/delicate objects by the actuation. This was achieved by designing a constant-force mechanism as the jaw that allowed a constant force to be applied to the grasping objects regardless of the displacement of the mechanism. The constant-force mechanism is attached to the end effector of the gripper via a parallelogram mechanism which ensures that the jaws remain in parallel. The constant-force mechanism combines the negative stiffness of a bistable mechanism and the positive stiffness of a linear spring to generate a constant force output. By preloading the positive stiffness mechanism, the magnitude of the constant force can be adjusted to be as low as zero. The constant-force mechanism has been fully modelled and simulated using finite element analysis. A normalised force-displacement curve has been developed that allows to obtain the simplified analytical negative stiffness of the bistable mechanism. The design formulation to find the optimal configuration that produces the most constant force has been developed. Illustrated experiments prove the concept of the design although the discrepancies between finite element analysis results and testing results exist due to bistable beam manufacturing error.

The effects of agglomeration on the density, morphology and subsequent reconstitution behaviours of milk powders were investigated. In this study, milk protein isolate, as a model system, was agglomerated in a fluid bed granulator with three different binders: water, lactose and sucrose solution ( 15% w/v ). Morphology was quantified by circularity, convexity and elongation. Wettability was measured by the modified Washburn method. Powders solubilisation was quantified by dynamic particle size measurement and the kinetics of dissolved solids concentration in solution. The results showed that granules with water as the binder produced significantly lowest circularity and convexity and highest elongation. An increase in the size of the agglomerated MPI corresponded with an increase in the wettability but a decrease in the ability of solubilisation in water. Granules agglomerated with hydrophilic sugars were found to contribute differently which improved the wettability significantly but no improvement for the kinetics of dissolution.

The absorption of steam bubbles in a hot aqueous solution of Lithium Bromide is a key process that occurs in the absorber vessel of a heat transformer system. During the condensation process, their size and shape changes dynamically with time as they rise up through the column of liquid. An understanding of the factors that control the vertical upwards motion of the bubbles is necessary to enable proper design of such units. However, the exact vertical displacement of a bubble moving through a liquid is difficult to predict and becomes much more complex if the bubble is simultaneously collapsing. In this paper, the displacement of steam bubbles collapsing in a concentrated aqueous lithium bromide solution (LiBr–H2O) has been quantified experimentally. A simple kinetic model predicting the vertical displacement as a function of time was then developed from elementary force–balance considerations. A key feature of the system is the large variability in the motion of the bubbles arising from extreme fluctuations in their size and shape. Bubble dynamic morphology was modelled with stochastic techniques and the output from this was used in the kinetic model to predict dispersion in bubble displacement with time. While the uncertainty predicted by the stochastic model is shown to be less than that observed experimentally, it nonetheless highlights the importance of this random behaviour during the design of such an absorption column.

Evaporation maps are a convenient way of representing the dynamic composition of evaporating liquid mixtures. Specifically, these maps represent the residual composition of evaporating ternary non-ideal mixtures over the full range of composition, and are analogous to the commonly used residue curve maps of simple distillation processes. The evaporation process considered here involves gas-phase limited evaporation from a liquid or wetted-solid surface, over which a gas flows at known conditions. Evaporation may occur into a pure inert gas, or into one pre-loaded with a known fraction of one or more of the ternary components. The model developed here uses an exact solution to the Maxwell–Stefan equations for mass transfer in the gas film, with a lumped approach applied to the liquid phase. Solutions to the evaporation model take the form of trajectories in temperature–composition space, which are then projected onto a ternary diagram to form the map. Efficient Newton-based methods are used to calculate the composition and temperature of pseudo-azeotropes in the mixture, and to calculate the wet-bulb temperature at a given composition. A numerical continuation method is used for tracking the bifurcations which occur in the evaporation maps, where the composition of one component of the pre-loaded gas is the bifurcation parameter. The bifurcation diagrams can in principle be used to determine the required gas composition to produce a specific terminal pseudo-azeotrope composition. Provided the gas-phase limited assumption applies, such analysis is applicable to applications such as drying of solvent-based coatings and tray-drying of granulated pharmaceutical products.

Vapour absorption heat transformers are thermodynamic cycles which are capable of upgrading the temperature of waste heat energy using only negligible quantities of electrical energy. Although marked as a future technology by the IEA (International Energy Agency), as being important for energy utilization in the 21st century, industrial applications of heat transformers are still very limited. This paper presents a comprehensive review of heat transformer research over the past two decades. Emphasis is placed upon optimisation studies, alternate cycle configurations, working fluids comparisons and industrial application case studies.

The filling of a cavity space with a powdered material to produce tablets, capsules or pellets is an important operation across a number of industries including pharmaceuticals, health-food supplements and animal feeds. Variability in the mass of the product must be controlled. The objective of this paper is to quantify the dispersion in the tablet mass as a result of non-uniformity in the amount of material deposited in the cavity by consideration of the basic statistics of the process. The system under analysis is where powder is poured into a cavity, allowed to overflow the cavity and the free surface swept horizontally. A statistical approach to the parameters that introduce variability into the system is adopted to quantify the resulting dispersion in weight. Theoretical expressions for the mean and variance in tablet mass are developed. It is shown that dispersion in tablet mass results from variability in powder size and in the number of particles deposited in the cavity together with the effects of random packing. The theory is validated using a model system of glass beads and then applied to a more realistic example of pharmaceutical particles. It is shown that as a result of this analysis there are approaches that can be used to reduce tablet weight dispersion.