MATHEMATICAL MODELS FOR BUFFER SIZING PROBLEMS IN PARALLEL ASSEMBLY LINES WITH MULTI-LINE STATIONS AND DIFFERENT CYCLE TIMES

In industry there are production systems consisting of more than one assembly line. If these are close together, it is possible for an operator to perform tasks from two adjacent lines assigned to his station (this will be a "multi-line station")

Inexpensive and easy method for 6 fragment Golden Gate Assembly of a modular S/MARs mammalian expression vector and its variants

A basic requirement for synthetic biology is the availability of efficient DNA assembly methods. Numerous methods have been previously reported to accomplish this task. One such method has been reported, which allows parallel assembly of multiple DNA fragments in a one-tube reaction, called Golden Gate Assembly. Here described is a simplified and inexpensive Golden Gate Cloning Protocol in which the amplified PCR fragments that enter the one-step-one-pot reaction are stored in Zymo DNA/RNA Shield at -20 degrees C and thawed whenever needed to be used as fragments or modules in the assembly. The protocol inludes the design step, in which fragments are designed to posses unique overhangs, amplification of modules using a high fidelity polimerase from preexisting plasmids or gene fragments, clean-up of the PCR products (fragments) in one tube, assembly, DpnI digestion for eliminating the background plasmids that remain after the PCR reaction and transformation of the resulting assembly reaction into competent E.coli cells. The protocol eliminates the need for vectors and inserts. The plasmid is build using only PCR products or fragments, with one of them containing the bacterial origin of replication and the antibiotic resitance gene for selection. Multiple modular plasmids can be constructed in just one day with minimal hands-on time.

EXISTENCE AND SIZING OF BUFFERS IN PARALLEL ASSEMBLY LINES WITH MULTI-LINE WORKSTATIONS AND DIFFERENT CYCLE TIMES

ABSTRACT: Parallel Assembly Lines with multi-line stations (PALBs) have been widely studied in recent years because PALBs can help improve the efficiency of a production system. However, the need of buffers has not been considered in the PALBP literature. In this study, for the first time in the literature, it is shown and demonstrated the need to consider the use of buffers in this type of line when their cycle times are different. Moreover, the buffer sizing problem in a multi-line workstation is presented and formalized. It is shown that the sequencing and scheduling of the task influences the buffer size. Finally, the designed resolution method is shown: solve a mixed integer linear programming model with a commercial software, with the objective of minimizing the size of the buffers. Keywords: Parallel assembly lines balancing, buffer sizing, task sequencing and scheduling.

Spatial ultrasound modulation by digitally controlling microbubble arrays

Acoustic waves, capable of transmitting through optically opaque objects, have been widely used in biomedical imaging, industrial sensing and particle manipulation. High-fidelity wave front shaping is essential to further improve performance in these applications. An acoustic analog to the successful spatial light modulator (SLM) in optics would be highly desirable. To date there have been no techniques shown that provide effective and dynamic modulation of a sound wave and which also support scale-up to a high number of individually addressable pixels. In the present study, we introduce a dynamic spatial ultrasound modulator (SUM), which dynamically reshapes incident plane waves into complex acoustic images. Its transmission function is set with a digitally generated pattern of microbubbles controlled by a complementary metal–oxide–semiconductor (CMOS) chip, which results in a binary amplitude acoustic hologram. We employ this device to project sequentially changing acoustic images and demonstrate the first dynamic parallel assembly of microparticles using a SUM.