Abstract: An online concierge system evaluates different parameters for order fulfillment in different geographic regions and evaluates order fulfillment in the different geographic regions to assess the different parameters. However, shoppers may fulfill orders in different geographic regions, causing spillover where order fulfillment by a shopper is affected by different parameters. To reduce spillover but still obtain a large number of zones for testing, the online concierge system generates a graph of geographic regions, with connections between geographic regions based on shoppers who fulfill orders in different geographic regions. The online concierge system generates a cluster including geographic regions connected to each other with a connection satisfying one or more criteria indicating at least a threshold percentage of shoppers fulfilling orders in each of the connected geographic regions.

Abstract: An online concierge system receives orders from users that include items from one or more warehouses. The online concierge system identifies the orders to shoppers, who select one or more orders to fulfill. The online concierge system uses models to estimate orders likely to be received at different times and shoppers likely to be available to fulfill orders at different times. Responsive to greater than a threshold difference between estimated orders and estimated shoppers during a time interval, the online concierge system selects one or more incentives for shoppers to select orders during the time interval to entice shoppers to select orders during the time interval. An interface displayed to the shoppers by the online concierge system may present a map of warehouses and their estimated number of orders and allow shoppers to identify incentives offered for fulfilling orders at different warehouses during the time interval.

Abstract: A scleral lens has an optical zone, a peripheral zone and a sagittal depth control zone between the optical zone and the peripheral zone. The sagittal depth control zone may be configured to raise the optical zone above the level of a person's eye when the scleral lens is in use and create a tear layer between the optical zone and the person's eye. Tear flow control features are provided in the sagittal depth control zone.

Abstract: A tankless water heater module is disclosed and includes a casing having a first end, a second end and a plurality of conduits formed therein. A top head manifold is coupled to the first end of the casing and includes a port aligned with each of the plurality of conduits. A bottom head manifold is coupled to the second end of the casing and includes a port aligned with each of the plurality of conduits. An immersion heating element extends through each port of the top head manifold and into the conduit aligned therewith. A flow path extends through the plurality of conduits, the plurality of conduits coupled in fluid communication by channels between ports of the top head manifold and a channel between ports of the bottom head manifold.

Abstract: Control circuitry is disclosed for use with a tankless water heater system including a plurality of water conduits connected in series. The control circuitry includes a plurality of water heater elements, one each associated with each of the plurality of water conduits. A controller includes a central processing unit (CPU) with an operating program and each of the plurality of water heater elements are coupled to the CPU. The CPU is programmed to individually activate one of the water heater elements to a predetermined power level in response to a demand for heated water. The number of water heater elements activated and the power level of the activation is determined by the demand for heated water.

Abstract: A fluid heating system includes a fluid supply conduit, a hot fluid conduit, and a fluid heating tube assembly. The fluid heating tube assembly includes an inlet coupling coupled to the fluid supply conduit, an outlet coupling coupled to the hot fluid conduit, and at least one fluid heating tube coupled between the inlet coupling and the outlet coupling. The at least one fluid heating tube includes a tube formed of heat conducting material, a dielectric coating permanently bonded on an outer surface of the tube, and a resistive layer permanently bonded on the dielectric coating. A power distributor is coupled to the fluid heating tube assembly and coupleable to a power source. A switch is coupled between the power distributor and the fluid heating tube assembly to control current flow from the power distributor to the at least one fluid heating tube.

Abstract: A roller guide for guiding the movement of an elevator car along guide rails disposed in a shaft or hoistway. The roller guide includes a base, a plurality of rollers and a plurality of support arms that rotatably support the rollers. An isolation assembly may be provided to reduce the transmission of undesired forces to the elevator car through the rollers, support arms and the base of the roller guide.