Robert J. Berry

Brookfield powder flow tester – Results of round robin tests with CRM-116 limestone powder:

A low cost powder flowability tester for industry has been developed at The Wolfson Centre for Bulk Solids Handling Technology, University of Greenwich in collaboration with Brookfield Engineering and four food manufacturers: Cadbury, Kerry Ingredients, GSK and United Biscuits. Anticipated uses of the tester are primarily for quality control and new product development, but it can also be used for storage vessel design. This paper presents the preliminary results from ‘round robin’ trials undertaken with the powder flow tester using the BCR limestone (CRM-116) standard test material. The mean flow properties have been compared to published data found in the literature for the other shear testers.

Review of the flowability measuring techniques for powder metallurgy industry

Abstract The flowability of bulk solids can be treated as one of the fundamental properties that determine their behaviour through industrial processes. Developing a standard meaningful test for measuring flowability has always been a challenge and numerous methods exist, based on the correlation of a number of physical properties such as gravity flowrate, internal strength, bulk density change, etc., which are thought to represent the ability of a powder to flow in some sort of a conceptual situation. Different industries have employed and standardized different techniques for flowability measurement, and the results these obtain may not correlate. The article details an investigation into the ability of various flowability measuring methods to detect small changes in the powder flow properties. Four flowability measuring methods, Hall flow, Hausner ratio, compressibility, and shear cell (manual and automated), were used to measure the flowability of four physically and chemically similar iron blends. Industry standard methods and the shear cell were not able to rank the blends with confidence. Influence of container wall friction is also investigated in the presented work.

Simulating and modelling the impact of security constructs on latency for open loop control

Open loop control has commonly been used to conduct tasks for a range of Industrial Control Systems (ICS). ICS however, are susceptible to security exploits. A possible countermeasure to the active and passive attacks on ICS is to provide cryptography to thwart the attacker by providing confidentiality and integrity for transmitted data between nodes on the ICS network; however, a drawback of applying cryptographic algorithms to ICS is the additional communication latency that is generated. The proposed solution presented in this paper delivers a mathematical model suitable for predicting the latency and impact of software security constructs on ICS communications. The proposed model has been tested and validated against a software simulated open loop control scenario, the results obtained indicate on average a 1.3 percentage difference between the model and simulation.

Study of two security constructs on throughput for Wireless Sensor multi-hop Networks

With the interconnection of devices becoming more widespread in society (e.g. internet of things), networked devices are used in a range of environments from smart grids to smart buildings. Wireless Sensor Networks (WSN) have commonly been utilised as a method of monitoring a set processes. In control networks WSN have been deployed to perform a variety of tasks (i.e. collate and distribute data from an event to an end device). However, the nature of the wireless broadcast medium enables attackers to conduct active and passive attacks. Cryptography is selected as a countermeasure to overcome these security vulnerabilities; however, a drawback of using cryptography is reduced throughput. This paper investigates the impact of two software authenticated encryption with associated data (AEAD) security constructs on packet throughput of multiple hop WSN, being counter with cipher block chaining and message authentication code (CCM) and TinyAEAD. Experiments were conducted in a simulated environment. A case scenario is also presented in this paper to emphasise the impact in a real world context. Results observed indicate that the security constructs examined in this paper affect the average throughput measurements up to three hops.

Balancing throughput and latency for an aerial robot over a wireless secure communication link

With the requirement for remote control of unmanned aerial vehicles (UAV) becoming more frequent in scenarios where the environment is inaccessible or hazardous to human beings (e.g. disaster recovery); remote functionality of a UAV is generally implemented over wireless networked control systems (WNCS). The nature of the wireless broadcast allows attackers to exploit security vulnerabilities through passive and active attacks; consequently, cryptography is often selected as a countermeasure to the aforementioned attacks. This paper analyses simulation undertaken and proposes a model to balance the relationship between throughput and latency for a secure multi-hop communication link. Results obtained indicate that throughput is more influential up to two hops from the initial transmitting device; conversely, latency is the determining factor after two hops.

Direct measurement of powder flavor adhesion onto crisp surface using a novel adhesion tester

A new experimental procedure has been implemented and a prototype of a novel adhesion tester has been designed and constructed using rapid prototyping technology. A tumbler mixer has been designed and constructed for coating powder material onto a crisp substrate. In the impact separation experiment, the amount of powder detached from one side of a crisp substrate by the effect of impact forces (48 g, 77 g, 102 g) generated by the tester was measured. Salt particles with different size fractions (63–125, 125–180, and 180–250 μm) and several flavoring powders have been tested extensively. By plotting the detachment versus impact force, the difference obtained between adhesion strength of different flavoring powders (which is a strong function of particle size and surface oil content of the crisp) has been discussed. The detachment rate of salt particles increased (from 1% to 2%) with particle size (from 63 to 250 μm) in the presence of oil on the surface of the crisp substrate and decreased rapidly with the increase in the amount of oil applied (from 0 to 1%).

A novel block cipher design paradigm for secured communication

Unmanned aerial vehicles (UAV) are commonly used to conduct tasks (e.g. monitor and surveillance) in various civilian applications from a remote location. Wireless communications (i.e. radio frequency) are often used to remotely pilot the UAV and stream data back to the operator. The characteristics of the wireless communication channel allows attackers to monitor and manipulate the operation of the UAV through passive and active attacks. Cryptography is selected as a countermeasure to mitigate these threats; however, a drawback of using cryptography is the impact on the real-time operation and performance of the UAV. This paper proposes the Permutation Substitution Network (PSN) design paradigm with an instance presented which is the Alternative Advanced Encryption Standard (AAES) and analysis of its performance against the standardised Substitution Permutation Network (SPN) design paradigm the Advanced Encryption Standard (AES). Results indicate that using the PSN paradigm is a feasible approach in comparison to the SPN design paradigm.

The Affect of Two Cryptographic Constructs on QoS and QoE for Unmanned Control Vehicles

Unmanned control vehicles are used for a variety of scenarios where the user can conduct a task from a remote location, scenarios include surveillance, disaster recovery and agricultural farming. The operation of unmanned vehicles is generally conducted over a wireless communication medium. The nature of the wireless broadcast allows attackers to exploit security vulnerabilities through passive and active attacks, consequently, cryptography is often selected as a countermeasure to the aforementioned attacks. This paper analyses simulation undertaken to identify the affect of cryptographic constructs on the Quality of Service (QoS) and Quality of Experience (QoE) of controlling an unmanned vehicle. Results indicate that standardised AEAD cryptographic approaches can increase the additional distance travelled by a unmanned vehicle over multiple hops communications up to 110 meters per second.

Breakage characteristics of granulated food products for prediction of attrition during lean-phase pneumatic conveying

Abstract Pneumatic conveying is utilised in a variety of industries to convey food products exhibiting diverse handling characteristics. Attrition of particles caused by this conveying process can result in a number of undesirable outcomes such as loss in product quality or issues in subsequent handling processes. The ability to predict the breakage behaviour of particulate materials is desirable in both new system design and resolving issues in existing plants. This work considers two different particulate materials (Salt and Golden Breadcrumbs) across a range of particle sizes, and quantifies their breakage behaviour under varying impact conditions. Narrow size fractions of each material were degraded; material retained on 250 µm and 355 µm sieves for Salt, and 500 µm, 710 µm and 1,000 µm sieves for Golden Breadcrumbs. Velocity was found to be the most influential factor with respect to particle attrition. The results from the narrow size fraction tests were superimposed to form a simulated full size distribution breakage behaviour, which was then compared to the experimentally determined behaviour. A good agreement was found, however the proportion of material predicted for size fractions smaller than 355 µm for Golden Breadcrumbs and 180 µm for Salt was under-predicted. Recommendations for increasing accuracy of the prediction method are given.

Testing of powders for sensitivity to air effect segregation

Abstract A loss of blend homogeneity through handling operations can have a major influence on the mechanical properties of sintered products. Plant optimisation to minimise the potential for segregation of blends can be undertaken through an audit of handling operations combined with an evaluation of the materials that are handled through the process. The correct identification of the mechanism of segregation is essential to support strategies to implement the most efficient and cost-effective counter measures. In support of this type of industrial activity, a piece of test apparatus has recently been developed to provide measurements of segregation potential for powders (metal and mineral) that are prone to loss of homogeneity (by composition or particle size) when subjected to counter-directional air displacements through equipment. The test equipment is described and examples given of its output in industrial application.